A dense colony of mealybugs.

Mealybugs are common pests of houseplants. They are pink, soft-bodied insects covered with a white, waxy, cottony material. The white “fluff” helps protect them from excessive heat and moisture loss. Unlike their relatives the scales, most species retain their legs throughout their life and can move around. Females are rounded, wingless, and about 1/16″ long.

The citrus mealybug (Planococcus citri) is the most common species found on plant foliage. It feeds on a wide variety of plants, and especially likes soft-stemmed and succulent plants such as coleus, fuchsia, croton, jade, poinsettia and cactus. In my greenhouse I also find them consistently on rosemary, citrus, and bird of paradise. Other mealybug species such as longtailed mealybug (P. longispinus) or cactus mealybug (Hypogeococcus festerianus) occasionally occur on specific host plants. These species remove plants sap from aboveground plant parts, especially stem tips, leaf junctures and new growth.

Citrus mealybug, the most common species of mealybug found on houseplants.

Their feeding weakens and stunts plants, and causes foliar yellowing, defoliation, wilting and general plant decline. In some cases, plants can be killed. Citrus mealybugs inject a toxin while feeding that causes plant malformation. Mealybugs also excrete honeydew, which allows for the growth of sooty mold.

Some mealybugs are root-feeders. The ground mealybug (Rhizoecus falcifer) is the most common soil mealybug, occurring on the roots of many house plants, especially African violets. Feeding on the root hairs results in yellowed leaves, wilting, stunting and bloom reduction. A few mealybug species will move to roots when growing conditions are less favorable, but return to stems and leaves when plants are actively growing.

A female mealybug and her cottony egg mass.

Female citrus mealybugs lay up to 600 small (1/100 inch or 0.3 mm long), yellow eggs within a protective mass of white, cottony threads. The longtailed mealybug does not lay eggs but produces live young, similar to aphids. After depositing the egg mass or live young over a period of 5–10 days, the female mealybug dies. The immatures search for feeding sites on which to settle. Male nymphs settle and spin an elongated, white waxy cocoon. Females have three instars and are mobile throughout their lives.

Citrus mealybug egg mass with newly hatched nymphs.

The best method for detecting infestations of mealybugs on leaves and stems is visual inspection – just looking at the plants. Both the insects themselves and the eggs in their masses of waxy threads may look like white cotton on the plant. On some plants mealybugs concentrate on the growing tips, and on other plants they are more dispersed. The longtailed mealybug frequently conceals itself in leaf whorls.

Underground infestations are more difficult to detect. Yellowed or wilting foliage may indicate the presence of mealybugs on the roots. Small white cottony masses around the drainage holes of pots also indicate the presence of mealybugs, but in many cases infestations can be confirmed only by removing the root-ball from the pot to observe mealybugs on the roots.

Control

Mealybugs on a hibiscus flower bud.

Mealybugs are difficult to get rid of because immatures typically wedge themselves in stem crotches, leaf folds, or other tight locations where washing or pesticides cannot reach them. The best way to control mealybugs on houseplants is to prevent them from being established in the first place. Carefully inspect all new houseplants before introducing them to your home, and keep them separate from other plants for a week or so if possible. Mealybugs can easily crawl from one plant to another, especially when leaves or branches overlap, so one contaminated plant could spread mealybugs to all your houseplants. Check under leaves, in new leaf folds, and around the growing tips for signs of infestation. Mealybugs like lush foliage, so avoid over-fertilizing with excess nitrogen.

A citrus mealybug nymph crawls along a leaf.

If mealybugs are present on only a few, small plants, you can try to reduce or eliminate infestations by washing off the plants. A moderately strong spray of warm water will dislodge most of the mealybugs. Alternatively, you can try wiping the insects and egg masses off the plants with a cotton swab or cloth dipped in rubbing alcohol. This is most effective on large-leaved plants (but test first on a small area to make sure the alcohol won’t damage the plant; it may take a day or two for symptoms to show). Washing rarely eliminates all the pests, so it is important to check the plants periodically and wash again or use other controls when more are noticed.

A mealybug crawls on a red coleus plant.

It may be helpful to prune out heavily infested plant parts when such pruning won’t damage the appearance of the plant. Dispose of plant cuttings immediately, since mealybugs can survive on detached plant parts for as long as those parts have moisture. Consider discarding a heavily infested plant and replacing it with a new, pest-free plant as one way to deal with a severe mealybug problem. Root infestations are particularly difficult to control, so this is often the most practical way of eliminating root mealybugs.

Chemical controls can be used to treat mealybugs. Less toxic alternatives such as insecticidal soap or horticultural oils can be effective, but must be applied to the hard-to-reach places the mealybugs inhabit to kill the insects. These may require several applications to achieve control. There are several registered insecticides available at garden centers that will control mealybugs. Read the label carefully to make sure the material is effective for mealybugs and for instructions on how to apply the pesticide.

A citrus mealybug.

A number of natural enemies, including several parasitic wasps and predators, are known to attack mealybugs. Some are used for control of mealybugs in commercial greenhouses, but most are not appropriate for use in the typical home. The mealybug destroyer, Cryptolaemus montrouzieri, is a small lady beetle that is a very effective predator, especially when mealybug numbers are high and many egg masses are present. It can be purchased commercially and should be released at the rate of 2-8 adults per plant. However, it will take some time for the beetles to reduce mealybug populations and may not eliminate it entirely.

– Susan Mahr, University of Wisconsin – Madison


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Have you ever found something on a houseplant that you first thought was a tiny piece of cotton, but then you realized was a living thing? Mealybugs can ruin the appearance of your indoor and outdoor plants and can cause a significant amount of damage. When left unchecked, mealybugs can eventually kill a plant. For such small creatures, mealybugs can be surprisingly hard to remove. They are found in warm, moist climates and can be introduced to your home and yard by new plants, tools or other materials.

Contents

Mealybugs: A Complete Guide To This Lawn Pest

In this post, we will tell you everything you need to know about mealybugs, including what they look like, their favorite hiding spots, their impact on our green spaces and, perhaps most importantly, what you can do if you find them feasting on your plants.

Tiny White Bugs On Plants Can Be Harmful

Those tiny white bugs you noticed while watering your plants might actually be a mealybug infestation. These tiny pests are typically white in color, which comes from a wax produced by special glands on the top and sides of their bodies. Mealybugs are related to aphids, which are also covered with waxy secretions, so these two insects are often confused.

Mealybugs are tiny creatures—sometimes only half a millimeter long—which often congregate on the part of the plant where the leaves attach to the plant’s stem. Aphids are more likely to leave behind residue in patterns on the backside of leaves or in a coating on a plant’s stem. Although it’s difficult to catch mealybugs on the move, you can sometimes notice active adults making their way across a plant’s leaves or stem. Do mealybugs fly? Only the adult males. Both insects can cause similar damage to your plants, and you can use some of the same tactics to control these pests.

All plant species are at risk for damage from a mealybug infestation. In warmer parts of the country, citrus and ornamental plants are more severely impacted by this lawn pest. Tropical plants, woody trees, shrubs, perennials and annuals can also be attacked by this pest. Mealybugs feed by sucking sap from plant roots, crowns, stems, twigs, flowers, fruit and leaves and leaving behind a honeydew-like residue which attracts ants. The sticky substance provides the perfect conditions for a sooty-colored mold to develop on the plant.

Mealybugs are experts at hiding on roots, in crevices and under lips and pots and planters. There are many species of mealybugs, all of which are very tiny. Some have longer tiny needle-like rods which look like tails, while others have longer rods extending around their bodies. Some species are more pink, yellow or light green in color, but most are white.

Where Do Mealybugs Come From?

Mealybugs are so small that they can come in undetected from a variety of sources: potting soil, other plants, fresh produce from the grocery store or farmers market. You are more likely to find mealybugs inside, but you can also find them outdoors. The pink hibiscus mealybug is a native of India and was first reported in Egypt in 1920. It spread to the Caribbean in 1993 and then quickly spread through the islands and up to Florida from there.

Other states such as Alabama, Arizona, California, Georgia, Louisiana, Mississippi, New Mexico, North Carolina, South Carolina and Texas also suffer economic losses because of the infestation of mealybugs on crops and ornamental plants in nurseries.

If you are wondering what attracts mealybugs, understanding that these pests prefer plants with high levels of nitrogen can lead you to be more judicious in applying fertilizer and water. Homeowners who overfertilize plants or keep plants moist may be unknowingly making their plants more vulnerable to an infestation.

Where to Find Mealybugs

Mealybugs can look like little pieces of cotton on your plant. They like to hide in hard-to-see areas like under the leaves and in crooks and crevices of plants like the leaf and stem axis. However, they will infest any area of the plant. When you just have one or two females, they can be harder to spot. However, once they start laying their egg sac or the eggs hatch, then they are much easier to spot because they tend to cover more areas of your infected plant.

Are Mealybugs Harmful to Humans?

Some mealybugs can spread viruses, but this is uncommon and primarily occurs with species which prefer grapevines. Mealybugs do not bite humans, although coming into contact with these creatures can sometimes cause skin irritation. The sticky residue mealybugs leave behind can be hard to remove from clothing. Wash your hands and clothing after coming into contact with mealybugs to avoid any potential impact.

The biggest threat mealybugs pose is to humans is economic. Damage from these pests to agricultural crops can be significant and homeowners may be forced to discard impacted plants in cases of an infestation.

Mealybugs on Succulents

These troublesome pests can be a major headache for succulent owners. Mealybugs are notorious for hiding in the plant crevices and sucking them dry, especially once the egg sacs hatch. Removing dead areas of the plant can help take away their hiding spots, as well as reduce the occurrence of mold on your plant.

Mealybug Life Cycle

Mealybugs start out as eggs and then move into larval and adult stages. Females lay up to 500 eggs in a cottony egg sac attached to plants, fruit, bark or twigs. After about 10 days, the egg sac hatches and the babies quickly spread out over the plant looking for feeding sites.

Adult male mealybugs are tiny two-winged insects are born without the ability to feed and die quickly. Their sole meaning for existence is to fertilize the females. In warmer climates, mealybugs can produce up to 8 generations in a single year. In more temperate areas, mealybugs only produce one or two generations annually.

Mealybugs in Florida

Pink hibiscus mealybugs, which are reddish-brown or pink with no noticeable filaments or stripes, were discovered in Florida in 2001. This species attacks many of Florida’s crops and plants, such as citrus, avocado, fig, guava, mango, sugarcane, asparagus, beans, beets, cabbage, peanuts, cucumber, lettuce, pepper, pumpkin, tomato, bougainvillea, hibiscus, palm and oleander.

This pest’s impact on agriculture is so significant that a professor from the University of Florida wrote a whitepaper about it, stating that, “The overall annual cost of control and damages to the US economy from PHM have been estimated to be US $700 million, with the global total being about $5 billion.”

In Florida, we mainly see the long-tailed, citrus, madeira, solanum, striped, solenopsis, papaya, Granara de Willink, Jack Beardsley and pink hibiscus mealybugs, according to the University of Florida.

Prevention

Before introducing a new plant inside or into your garden, inspect it for mealybugs and other insects. They can be found hiding in protected, hard-to-see areas of the plant, like the underside of leaves, stems, touching leaves and leaf axils. Remember to check everything before introducing it into your house or garden: the soil, leaves, stems, fresh produce and garden tools.

If you catch a mealybug infestation early, you can usually cut off the infected parts of the plant to prevent it from spreading.

As we mentioned earlier, mealybugs are attracted to high nitrogen levels, so don’t overwater or over fertilize your plants.

Mealybug Removal Tips

Mealybugs are notorious for being some of the most difficult to remove pests for homes and greenhouses. If you can catch them before the infestation grows, your likelihood of success is higher. Here are some tips for trying to rid your plants of mealybugs:

  • Be sure to remove any infected plant away from healthy plants as soon as possible.
  • Many people recommend putting alcohol on a Q-tip and applying it to infected areas. We’ve also heard of people putting the alcohol in a spray bottle and spraying that on the plant. If you try this, be judicious about how much you spray, so that you don’t damage the plant.
  • Spraying your plants with high-powered water can also remove these pests.
  • Ladybugs eat mealybugs. By introducing beneficial insects, including lacewings, syrphid flies and small parasitic wasps, you can help reduce mealybugs on your outdoor plants.
  • Insecticidal soaps and dish soap have also been known to get rid of small infestations.
  • Pruning infected leaves or stems can also help rid them from your plant.
  • Introducing the Cryptolaemus montrouzieri is another way to combat these pests, since this beetle is known to feed on mealybugs.
  • Throwing away the infected plant.

ABC Will Help Protect Your Plants

Since mealybugs are so tiny, prolific and expert hiders, an infestation can crop up quickly. If you experience an infestation or have trouble handling the problem on your own, the professionals at ABC Home & Commercial Services can help devise a plan to treat the mealybugs, as well as the ants that are attracted to the sticky residue they leave behind. The earlier you schedule service, the quicker the experts at ABC can help rid your plants of these pests before they destroy your plants and garden.

Home Remedies to Kill Mealybugs

Mealybugs are a nightmare for any gardener, apart from being extremely unpleasant to look at, they are also very harmful for the health of plants.

Mealybugs or woolly aphids as they are called, are small white insects that are usually found in warm and moist areas. They attach themselves to areas of the plant that are hidden and feed off them causing them to wither. They secrete a cotton like layer of wax and look like they are covered with flour, hence the name. This layer of wax protects the bugs and makes it very difficult to kill them. If left untreated, mealybugs can kill a plant. Hence, it is extremely important to use effective methods and eliminate them at the earliest. They can be killed using pesticides available in the market, but if you are looking for some home remedies to kill mealybugs, scroll down.

Spray Water in Full Force

An easy way to get rid of mealybugs in the early stage is by simply spraying water at full force on the plants. If your house plants are infested, take them out and spray some water on them. Due to the force of water, the bugs will fall off the plant. Repeat this procedure two to three times a week, this way you will even get rid of small insect eggs and webs on any part of the plant.

Wipe with a Damp Cloth

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This is another simple method to get rid of mealybugs, try it before you opt for any other fancy method. Take a clean cloth, make it wet and wring out excess water, we want it slightly damp and not dripping with water. Use this damp cloth gently to wipe all the leaves, the top and the bottom. This will help get rid of bugs and their eggs from plants. You can use this method if the issue is with just a couple of house plants.

Spray Soap Water

If the damp cloth is not enough to take care of the infestation, you can try using soapy water. Mix one tablespoon of dish washing soap with one pint of warm water and spray on the infested plants. The soap will penetrate through the wax layer and kill the bugs. Use a mild soap with no fragrance or additives, as they can be harmful to the plants. Soap may cause slight spotting in leaves, to take care of that, spray some water after the soap mixture dries.

Rub Isopropyl Alcohol

Isopropyl alcohol is very effective in getting rid of mealybugs. Take a few cotton swabs, dip it in alcohol and wipe the part of the plant that is infested. Bugs die immediately as soon as they come in contact with alcohol. This method is effective, but extremely time-consuming. If there is a large colony of bugs on the plant, pour the alcohol directly on the bugs to kill them. Do not use any other alcohol, as it can be harmful to the plant.

Spray a Mixture of Soap, Alcohol and Water

To make an even more effective mixture, mix alcohol, liquid soap and water. Combine equal quantities of water and alcohol to make about one and a half liter of the mixture. Mix approximately one tablespoon of liquid soap in the mixture and spray on the infested plants. The combination of alcohol and soap is highly effective and works well in eliminating the pest. Spray this mixture regularly on plants, to get rid of mealybugs completely.

Apply a Little Oil

Oil is also known to help get rid of mealybugs on plants. The thick oil causes insects to suffocate and die. To make an effective oil solution, combine 1 gallon of water with about 2 tablespoons of vegetable oil. Apply this mixture on the infested plants, once a week, till the pests are under control. Be careful to apply the mixture thoroughly on the plant, as the bugs tend to hide below the leaves and the undersides of the plant.

Use Natural Predators

You can also control mealybugs by using predators of mealybugs such as lady bugs, spiders, lace wing, etc. These insects can be easily purchased online and will be delivered to your house. They work well for plants that are kept outside, release a few insects at a time. Also be careful to control ants, as they feed on the honeydew that the bugs produce and protect them to get regular food supply.

Other Home Remedies

Apart from the above mentioned remedies, you can also use a mixture of garlic, vinegar and hot sauce. Similarly, you can also use jalapeno juice or a mixture of cayenne pepper, hot water and Tabasco sauce and spray it on the plant. All these combinations act as natural insecticides. Instead of using dish washing soap in the soapy water mixture, you can opt for peppermint soap, as bugs do not like the strong smell of peppermint. You can also use Murphy’s oil soap with water.

Use these above mentioned home remedies to protect your plants from mealybugs. Always make sure to test the solution on a small part of the plant before generously spraying it, to avoid destroying the plant.

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Most people want to know – How To Get Rid of Mealybugs – after they have seen mealybugs on their indoor plants or on other ornamental plants in the landscape.

If you have noticed what looks like small pieces of cotton or blotches of powder all over the leaves, those small, fuzzy, tiny white bugs on plants are probably mealybugs.

If you’ve seen them, naturally, mealybug control will be a priority.

What Do Mealybugs Look Like And Why Control is Necessary?

Mealybugs are white, soft-bodied, cottony-looking insects with a protective waxy coating, and equipped with piercing/sucking mouth parts under order hemiptera.

They are like plant scale insects and aphids in that they suck the fluids from green leaves and stems, robbing plants of essential nutrients.

Mealybugs excrete large amounts of honeydew, this makes an excellent “growing soil” for a black fungus called sooty mold. Some of the known species of mealybugs that are likely to infest your home and garden include:

  • Pink hibiscus mealybug (Maconellicoccus hirsutus)
  • Vine mealybug
  • Citrus mealybug (Planococcus citri)
  • Grape mealybug
  • Longtailed mealybug (Pseudococcus longispinus)
  • Pineapple mealybug
  • Obscure mealybug (Pseudococcus viburni)

Sooty mold is unattractive and interferes with photosynthesis, it can also retard the growth of the plant.

This can also make the leaves and floors sticky. Sooty mold usually whithers away after removing the mealybug.

Related: Organic Natural Pest Control Without Pesticides

Watch For Ants Feeding On Mealybug Honeydew

Where do mealybugs come from?

Ants feed on the honeydew when you find ants crawling around your plants indoors or out or observed making a nice trail from a plant.

Take some time to examine your houseplants closely for these sucking pests.

These annoying white bugs on plants do well indoors – they love and live very well in warm, dry environments. These pests have a life cycle of about 30 days.

These crawlers normally call home and adult females deposit their eggs where leaves join stems or along leaf veins. When the eggs hatch, their feeding will cause leaves to turn yellow and drop.

Damaged plants look withered and may have a sticky sap on the leaves or stems.

Mealybugs On Houseplants – What Plants Get Them On The Most?

Some of the indoor plants most commonly affected by mealybugs include:

  • The African violets pests include root and foliar mealybug
  • Aglaonema
  • Cactus and Succulent pests
  • Dracaena plants
  • Ferns
  • Palms
  • Ficus – weeping fig
  • Pothos plants – Green Jade, Golden & Marble Queen
  • Philodendron
  • Norfolk Island Pine – Araucaria Plant
  • Schefflera
  • Jade succulent with yellow leaves falling off
  • Spineless Yucca Elephantipes

How To Get Rid Of And Control Mealybugs On Plants

Here’s how to kill mealybugs.

As with soft scale insects, an easy method of control is to apply alcohol with cotton swabs directly on the mealybug.

Wiping down the foliage regularly and helping plants clean will help keep these white fuzzy bugs in check.

For a mealy bug insecticide, if a plant becomes severely infested consider using safe natural organic neem oil sprays to control the pest or make your own homemade insecticidal soap or possibly horticultural oils.

Neem can be found at your local garden center. Always read the pesticide label and wear appropriate safety equipment when applying any chemical.

For heavy infestations of mealy bugs that are hard to reach, try spraying directly on the insects a mixture of 10 percent rubbing alcohol and 90 percent water. Repeat applications weekly until the bugs are gone.

Always test any insecticidal soap and alcohol mixtures on a small portion of the plant prior to full application as some plants may be sensitive to soap or alcohol. Systemic insecticides are another possibility, although I try to avoid them.

How To Get Rid Of Mealybugs On Orchids?

Here’s how to get rid of mealy bugs.

Mealy Bug feeding on the buds of Phalaenopsis moth orchid

Prevention is the best way to get rid of mealy bugs on orchids. These pests can come from a number of sources, such as:

  • Plants that have been allowed to spend time outside during the warm months
  • Fresh produce or flowers (either purchased or brought in from outdoors)
  • Put in place by ants seeking to set up a “farm” to harvest honeydew
  • New plants introduced to your collection
  • Use of contaminated potting medium

Whenever you purchase a new plant, bring plants or produce in from outdoors, inspect thoroughly for mealybugs and ants!

Quarantine new plants for a couple of weeks to avoid introducing pests to your orchids and other houseplants.

Kill The Mealybugs When You See Them

Luckily, mealybugs are susceptible to many non-toxic home remedies so you do not have to use toxic pesticides in your home to get mealybugs off your orchids.

One of the simplest and most popular treatments is simply to use a cotton swab dipped in rubbing alcohol on these pests when you see them. Rubbing alcohol will kill them on contact.

Don’t just treat the obvious ones, though. Inspect the entire orchid to find any that may be lurking in the leaf joints, under leaves, in the substrate or in crevices in the container.

To eliminate mealybugs check frequently and treat repeatedly to be certain of killing them all.

Treat Mealybugs On Orchids With Homemade Insecticidal Soaps

Make an effective mealybug treatment (insecticidal soap) using a mild spray mix using a liter of distilled water and a teaspoonful of organic liquid castile soap. Doctor Bronner’s makes a good product.

Check Out our Homemade Recipe For Insecticidal Soap

You can also make a liter of orchid-safe mealy bug spray by combining distilled water and isopropyl alcohol 50/50 along with a teaspoonful of liquid castile soap in a spray bottle.

Spraying alcohol will help kill off mealybug eggs.

Spray on the plant (orchids) lightly, early in the day. Be sure they are in an area that has bright, indirect light and good air circulation so that the water and spray will dry thoroughly.

You don’t want your orchid leaves to stay damp for an extended period of time.

Heavily infected orchids can be rinsed in a castile soap and water solution, rinsed and allowed to dry thoroughly.

It is not a good idea to spray or rinse blossoms or buds. If mealybugs infest an orchid in bloom, it’s best to sacrifice the blossoms by pruning them to save the plant.

Neither rubbing alcohol or mild insecticidal soap have residual effects, so you will need to treat repeatedly over several days to eradicate all the pests.

Check back daily to be sure the job is complete.

Neem Oil Has A Residual Effect

A mild solution of organic neem oil is also safe to use on orchids.

This natural pest control product is very versatile, and you are sure to find lots of uses for it on all your houseplants and in your garden.

Be sure to follow packaging directions carefully when using the concentrate to make foliar sprays and soil drench solutions.

Even with its residual effects, neem oil should be applied several times for best results.

8 Step Process For Orchid Mealybug Control And Eradication

Follow these eight steps to get rid of mealybugs and keep them away:

#1 – Be vigilant! Examine all plants and their containers thoroughly for mealybugs on a regular basis.

#2 – Inspect all of your plants and treat as needed.

#3 – When you see mealybugs, act immediately.

  • Wash heavily infested orchids with a mild insecticidal soap solution.
  • Use a cotton swab with alcohol to treat mild infestations.
  • Change container and substrate if necessary.
  • Prune blossoms if necessary.

#4 – Wash down your plant area using a strong solution of soapy water. Finish up by spraying the area with rubbing alcohol and wiping it down again.

You can add a little neem oil to the alcohol spray for added residual effect.

#5 – Quarantine affected plants – make sure they are not touching any other plants and treat with neem oil spray.

#6 – Carefully observe the affected orchid. Check it every day and use a cotton swab dipped in isopropyl alcohol to kill off any mealybugs that may reappear.

#7 – If you still see mealybugs after a week, treat with neem oil spray again.

#8 – Keep the orchid in quarantine for several weeks. When you no longer see any sign of mealybugs, you can put it back in your collection.

Keep A Clean Plant Area

Mealybugs are able to hide in crevices and remain alive in a dormant state even when plants are not present.

Be sure to move your plant collection and wipe down all surfaces with soap and water and rubbing alcohol on a regular basis.

Check and wipe down the bottoms of containers and saucers and all equipment used to care for your orchids and other houseplants.

Mealybugs can hide out in orchid potting medium and regular potting soil.

If they are a recurring problem, you may need to repot orchids and other plants with fresh, new substrate.

When you repot orchids, be sure to clean and treat the roots with a mild insecticidal soap solution. Rinse thoroughly before placing the plant in its new substrate.

How to Get Rid Of Mealy Bugs On Succulents?

Mealybugs are susceptible to all sorts of pesticides and homemade pest control solutions, but one of the simplest and most affordable for use with succulents is 70% isopropyl alcohol.

These pests can be killed on contact with a little rubbing alcohol on a cotton swab, or you can simply spray your succulents with straight rubbing alcohol to kill off both the pests and their eggs.

In cases of heavy infestation, you can even use straight rubbing alcohol as a soil drench to kill the bugs and their eggs in the soil surrounding the plant.

Quarantine Affected Plants

When you see mealybugs on one of your succulents, be sure to remove or separate it from your collection. It is helpful to give plants a good drenching and keep it apart for a couple of weeks.

Check every day and treat for mealybugs as needed by spraying. Check all parts of the plant and its pot for any bugs that may be hiding in crevices.

Take special care to inspect the base of the stem as these bugs like to hide in the soil surrounding the plant. Spray or drench this area liberally.

It’s also a good idea to clean up your plant area with a strong solution of detergent and water and treat other members of your succulent collection with rubbing alcohol.

It won’t hurt them, and it may help prevent a major infestation. Many enthusiasts simply keep a sprayer bottle of isopropyl alcohol close at hand for regular treatments.

For more details read our Mealybugs on Succulent Plants article.

Is Straight Rubbing Alcohol Really Safe For Succulents?

For succulents, regular use of rubbing alcohol does not seem to be harmful. It kills the pests on contact and then it evaporates quickly, so it doesn’t have a chance to damage plants or roots.

Most succulent enthusiasts agree that isopropyl alcohol is the most affordable and simplest solution for getting rid of mealy bugs on succulents.

However, if you don’t want to use alcohol or don’t have it on hand, try adding a teaspoonful of dish soap to a quart of water to make a spray.

If you have an outdoor succulent garden, be sure to keep a healthy population of natural predators, such as Lady Bugs.

Vigilance Is Key To Defeating Mealybugs

If you can catch mealybugs before they have a chance to reproduce much, you should be able to keep them under control or even eradicate them with the rubbing alcohol method.

Just be sure to treat infestations repeatedly until you see no more mealybugs. Continue to spray and perform preventative measures on a regular basis.

https://www.succulentsandsunshine.com/kill-mealybugs-on-succulents/

All Natural Mealy Bug Control With Beneficial Insects

Using beneficial insects or natural enemies for biological control of mealybugs is another option.

For example, one mealy bug killer is the beneficial insect also known as the “Mealybug Destroyer” or Cryptolaemus montrouzieri technically and as “Crypts” for short.

They, like the excellent garden friend the ladybug, Cryptolaemus montrouzieri are lady beetles. Unlike the ladybug, these beneficial insects hang around after release and do not disappear.

Leptomastix dactylopii makes another natural enemy of mealybugs. They are parasitic wasps that attack the citrus mealybugs.

You can also go for other mealybug destroyers that also go after nymphs, aphids, spider mites, fungus gnats, and more.Image: Forest and Kim Starr | puuikibeach

Mealybug

Mealybug, (family Pseudococcidae), any of a group of small sap-sucking insects (order Homoptera) that are worldwide in distribution and attack citrus trees and ornamental plants, especially in interior plantscapes and greenhouses. Observed most frequently is the ovoid, sluggish mature female, about 1 cm (0.4 inch) long.

mealybugMealybug.Frank Vincentz

The name mealybug is descriptive of the insect’s body, which is covered by a white sticky powder resembling cornmeal. The females and “crawlers,” or active young, cluster along the veins on the undersides of leaves. Males are active fliers and have only two wings. Common members of the Pseudococcidae are the citrus mealybug (Planococcus citri) and the citrophilus mealybug (Pseudococcus calceolariae). Biological control and insecticidal soaps, horticultural oils, and traditional insecticides have been effective against these pests.

citrus mealybug (Planococcus citri)A citrus mealybug (Planococcus citri; order Homoptera).Encyclopædia Britannica, Inc.

Mealybugs are related to scales, whiteflies, and aphids.

How to Manage Pests

UC Pest Management Guidelines

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Grape

Vine Mealybug

Scientific name: Planococcus ficus

(Reviewed 7/15, updated 4/19)

In this Guideline:

  • Description of the pest
  • Damage
  • Management
  • Important links
  • Publication
  • Glossary

DESCRIPTION OF THE PEST

Vine mealybugs are small (adult females are about 1/8 inch in length), soft, oval, flat, distinctly segmented, and covered with a white, mealy wax that extends into spines (filaments along the body margin and the posterior end). The vine mealybug has a pinkish body that is visible through the powdery wax, and it is slightly smaller than the Pseudococcus mealybugs. The waxy filaments that protrude from the body of the vine mealybug are shorter than those on the Pseudococcus mealybugs, and the vine mealybug does not possess long tail filaments. The adult male is smaller than the female, has wings, and flies short distances to mate. There are three to seven generations a year.

All or most life stages of the vine mealybug can be present year-round on a vine depending on the grape-growing region. In the North Coast during winter months, the only life stages found are nymphs located under the bark predominately at the graft union, on trunk pruning wounds, and below the base of spurs. In other regions during the winter months, vine mealybug eggs, crawlers, nymphs, and adults are under the bark, within developing buds, and on roots.

As temperatures warm in spring, vine mealybug populations increase and become more visible as they move from the roots or trunk to the cordons and canopy. By late spring and summer, vine mealybugs are found on all parts of the vine: hidden under bark and exposed on trunks, cordons, first- and second-year canes, leaves, clusters, and roots. Ants may transport vine mealybug from the roots to above ground plant parts where they continue to tend vine mealybugs throughout the remainder of the growing season.

In the North Coast, vine mealybug has not been found on vine roots; however, in other regions with sandy soils it spends the winter almost exclusively on the root system. Other mealybugs found infesting grapes are only found on the aboveground portions of the vine. In addition, the vine mealybug is much more likely to be found on leaves during the growing season than the other mealybugs. During summer when vine mealybugs are in the canopy, they can be located well above the fruit zone and will lay eggs on the leaves, while Pseudococcus mealybugs do not. Vine mealybug does not diapause during the winter, and it appears to be more sensitive to cold temperatures than grape mealybug.

DAMAGE

Damage by the vine mealybug is similar to that of other grape-infesting mealybugs in that it produces honeydew that drops onto the bunches and other vine parts and serves as a substrate for black sooty mold. If ants are not present, a vine with a large population of this pest can have so much honeydew that it resembles candle wax. Also, the mealybug itself will be found infesting bunches making them unfit for consumption. Like the grape, obscure, and longtailed mealybugs, vine mealybug can transmit grapevine leafroll-associated viruses.

MANAGEMENT

Vine mealybug occurs in all major California production areas. In California, the vine mealybug feeds predominantly on grapevines, although in other countries it can be a pest of fig, date palm, apple, avocado, citrus, and a few ornamentals.

Because several different species of mealybugs may infest grapevines, it is important to know which species of mealybug is present because management programs for the various mealybugs differ. If you find mealybugs in your vineyard, collect the largest mealybugs you can find and place them in a jar of alcohol or sealed plastic bag. Take the sample to either your University of California Cooperative Extension (UCCE) farm advisor or county Agricultural Commissioner.

Biological Control

The parasites that attack Pseudococcus mealybugs do not attack the vine mealybug; therefore two potential candidates for biological control have been imported and released in California. The most successful of these has been Anagyrus pseudococci. This species has provided up to 20% parasitism in some vineyards in the Coachella Valley and up to 90% parasitism of exposed mealybugs late in the season in the San Joaquin Valley. This parasitoid can be highly effective late in the season to reduce mealybug populations present after harvest before they return to the roots or lower trunk to overwinter. However, in the spring, the parasitoid does not emerge from its overwintering state until about bloom, providing minimal mealybug suppression during the early and midseason. Growers can attempt to overcome this biological limitation of A. pseudococci by doing early-season releases of parasitoids that are purchased from commercial insectaries. Management of ants can reduce disruption of parasitism by A. pseudococci.

In coastal regions, several lady beetles such as the mealybug destroyer, Cryptolaemus montrouzieri and Hyperaspis sp. attack vine mealybug eggs and crawlers. Larvae of predaceous midges (family Cecidomyiidae) feed on mealybug eggs.

Cultural Control

The female and nymphal mealybugs are wingless and are unable to fly so they must be carried by humans, equipment, wind, birds, or be present on vines at the time of planting. Do not allow contaminated equipment, vines, grapes, or winery waste near uninfested vineyards. Movement of equipment that pushes brush or any over-the-row equipment can be a major source of infestations in new locations; steam sanitize equipment before moving to uninfested portions of the vineyard. Do not spread infested cluster stems or pomace in the vineyard. To reduce contamination, cover all pomace piles with clear plastic for several weeks, and avoid creating piles that consist predominately of stems.

Reduce cluster infestation by pruning vines to prevent clusters hanging directly on the cordon. In areas where mealybugs overwinter exclusively on the roots, band application of Tanglefoot onto duct tape that has been wrapped around the trunk (with the bark removed) may help slow crawler movement up the vine in the spring.

Organically Acceptable Methods

Biological and cultural controls are organically acceptable management tools. Repeated applications of oil approved for organic production can suppress vine mealybug in wine and raisin grapes. Oil applications are not used in table grapes, because they potentially affect the appearance of the fruit surface. Additionally, there are concerns about using oil in conjunction with sulfur due to the potential phytotoxic effects. Mating disruption is also approved for organic vineyards.

Monitoring and Treatment Decisions
Monitoring

Monitor for vine mealybug by doing searches on the roots, trunk, cordon, leaves, and clusters depending on the time of year.

During the winter, look for vine mealybug on the lower crown; in areas with sandy soils, on the roots. During budbreak follow the monitoring guidelines in DELAYED-DORMANT AND BUDBREAK MONITORING (wine/raisin grapes or table grapes) to monitor these and other pests and record results on a monitoring form (example form—PDF).

In the spring, monitor the crown and trunk for adult females and the presence of crawlers moving up the vine. Starting at bloom, monitor for vine mealybug along with other pests as outlined in MONITORING INSECTS AND SPIDER MITES. Survey cordons, canes, and basal leaves. In coastal areas, also continue to monitor the trunk.

When fruit is present, especially after veraison, monitor clusters to ensure vine mealybug life stages or honeydew are not contaminating the fruit. In table grapes and other hand-harvested vineyards, picking crews can be trained to be a valuable resource for reporting the presence of mealybugs in vineyards not known to be infested.

Monitoring efforts can be aided by looking for ants and honeydew. Argentine and gray ants tend vine mealybugs; therefore, observing ant activity can direct ones attention to where mealybugs are present on the vine. The presence of honeydew may also be an indication of vine mealybug presence. Thus, when searching for vine mealybugs during summer, look for honeydew exudates on the clusters, trunk, and cordons. These exudates will resemble melted candle wax; if the infestation is severe, basal leaves will appear shiny and sticky. Eventually, sooty mold will grow on the honeydew and permanent parts of the vine will appear greenish black during the fall and winter.

Pheromone traps can help determine if vine mealybug is present within or near your vineyard. Place pheromone lures in small red delta traps in and around the vineyard by April 1 in the southern San Joaquin Valley, by May in areas further north, and by June in the North and Central Coast region:

  • Choose two trap sites for each 20-40 planted acres.
  • Put one trap in the center of the block and the other on the edge near a staging area. These traps can attract vine mealybug males from as far away as 1/4 mile.
  • Attach traps to the trellis wires so that they are in the cluster area.
  • Label the trap with the block name and row number of its location and the dates it remains in the vineyard.
  • Check traps for the presence of male vine mealybug every 2 weeks through November.
  • Follow the manufacturer’s recommendations for storing and replacing pheromone lures.
  • Record observations on a monitoring form (example form (PDF)

It is essential to use a dissecting microscope to identify the male mealybug. (Male vine mealybugs are smaller than adult thrips and are very difficult to see even with a hand lens.) The sex pheromone is specific to the vine mealybug, but the traps may also contain other male mealybugs depending on the site. If there are questions as to the identification of the mealybug species, take samples to a farm advisor or county agricultural commissioner or refer to the Male Vine Mealybug Identification Sheet.

The number of males found in a trap depends upon its proximity to the infestation and to the time of year. In the North Coast, new infestations have been located near traps that caught very low numbers in June (5 to 10 males per trap per week) and high numbers in fall (more than 50 males per trap per week). In the San Joaquin Valley, an infested vineyard will have between 20 to 300 or more males per trap per week. In either region, low numbers of male vine mealybugs found in a trap may mean that the infestation is located in an adjacent block or in a more distant vineyard. If males are found, increase the number of traps in the vineyard, and locate the infestation by examining lower leaves for honeydew.

Treatment

If vine mealybug is found in a vineyard, treatment is recommended. However, the level of treatment varies greatly depending on the region, type of grape, and harvest date:

  • Coastal regions only have two to three generations of vine mealybug per year, compared to five to seven in the lower San Joaquin Valley.
  • Table grapes have no allowance for mealybugs in the cluster, while wine grapes can tolerate low levels.
  • Harvest dates vary widely in table grapes. Fruit from a Flame Seedless vineyard, harvested on the first of July, is less susceptible to damage than fruit in a neighboring Crimson Seedless vineyard, which might be harvested in October.

Due to the complexity of these and other factors, such as biological control, decisions about the level of mealybug control need to be made on a vineyard-by-vineyard basis.

In vineyards with low mealybug pressure, a single insecticide application in the spring or at bloom is often sufficient for season-long mealybug control. Effective control in heavily infested table grape vineyards, planted to a late-harvested variety, may require three or more treatments.

When treating for vine mealybug, consider other pests. Chlorpyrifos is also effective on ants, insect growth regulators can control scale pests, spirotetramat provides suppression of nematodes and phylloxera, and neonicotinoids are effective against sharpshooters and leafhoppers. When using soil-applied neonicotinoids, growers should also be cognizant of soil type: imidacloprid (Admire Pro) and clothianidin (Belay) are more effective on sandy soils whereas thiamethoxam (Platinum) and dinotefuran (Venom) are more effective on heavier soil.

Mating disruption has recently become available and can be used as an alternative or supplement to chemical control. Mating disruption is most effective when insecticides are used aggressively in the first year to reduce vine mealybug to low densities. In subsequent years, mating disruption supplemented with insecticides (as needed) can maintain the population at low levels. Mating disruption is most effective when applied over a large area (10 acres or greater). Greater success has been achieved in northern California, where there are fewer generations of vine mealybug per year.

Common name Amount per acre** R.E.I.‡ P.H.I.‡
(Example trade name) (hours) (days)
The following are ranked with the pesticides having the greatest IPM value listed first—the most effective and least harmful to natural enemies, honey bees, and the environment are at the top of the table. When choosing a pesticide, consider information relating to air and water quality, resistance management, and the pesticide’s properties and application timing. Not all registered pesticides are listed. Always read the label of the product being used.
DELAYED DORMANT
A. CHLORPYRIFOS*
(Lorsban Advanced) Label rates 24 35
MODE-OF-ACTION GROUP NUMBER1: 1B
. . . PLUS . . . (optional)
NARROW RANGE OIL
(Superior, Supreme) 1–2 gal See label See label
MODE OF ACTION: Contact including smothering and barrier effects.
COMMENTS: In spring, ants in southern California and the Central Valley move the female mealybugs from the roots to plant parts above ground. Spray to obtain thorough coverage of all aboveground plant parts, especially the trunk and cordons where mealybugs are located. Insecticide residues at the base of the vine will help control vine mealybugs in spring when they are being transported up the vine. Most effective when applied during warm weather (60°F or higher) because mealybugs are most active at this time. Apply during January for grapes harvested in June in the Coachella Valley. Do not apply in the North Coast; mealybugs are hidden under the bark at the graft union at this time of the year. Use allowed under a 24(c) registration (SLN CA-080009). Use chlorpyrifos for either ant control or mealybug control, but not for both pests on the same grape crop. Do not apply it between budbreak and harvest. Avoid drift and runoff into surface water. Chlorpyrifos has been found in surface waters at levels that violate federal and state water quality standards. Certain formulations emit high amounts of volatile organic compounds (VOCs); use low-VOC formulations. Regulations affect use for the San Joaquin Valley from May 1 to October 31, 2019. Additional application restrictions may apply; for more information on current California permit restrictions, see the Department of Pesticide Regulation’s Chlorpyrifos Interim Recommended Permit Conditions.
MATING DISRUPTION
A. LAVANDULYL SENECIOATE-sprayable
(CheckMate VMB-F) 0.89 fl oz 4 NA
COMMENTS: Make the first pheromone application in the spring just before male emergence or when males are first detected in pheromone traps (usually in May). Reapply pheromone every 30 days for the period of time mating disruption is desired (typically May through October). Applications can be made as a tank mix with most pesticides that are not EC formulations or that do not contain oil. If pheromone is being applied by itself, applications can be made to every other row. An application rate of 5 g a.i./acre is sufficient to disrupt mating for 30 days. Higher application rates are allowed on the label but are not necessary.
B. LAVANDULYL SENECIOATE-dispenser
(CheckMate VMB-XL)# 250 dispensers NA NA
COMMENTS: Apply in the spring just before male emergence or when males are first detected in pheromone traps. Place dispensers on canes or trellis wire in the upper one-third of the canopy or higher. Most effective in large blocks or areawide, and when vine mealybug numbers are low. In sites with medium-to-high numbers, use an insecticide to reduce numbers.

EARLY SPRING

A. BUPROFEZIN
(Applaud) 12 oz 12 7
MODE-OF-ACTION GROUP NUMBER1: 16
COMMENTS: An insect growth regulator. Good coverage is essential. Buprofezin targets young nymphs on the vine that are exposed and still moving around before they settle down under the bark to feed. In regions outside of the North Coast, apply once in the delayed dormant period and once in early summer (May or June). In the North Coast, the first application is during late spring when crawlers are present or early summer. Do not tank mix.
BLOOM
A. SPIROTETRAMAT
(Movento) 6–8 fl oz 24 7
MODE-OF-ACTION GROUP NUMBER1: 23
COMMENTS: A foliar insecticide that is absorbed by the leaves and moves systemically in the phloem and xylem. Use with a non-ionic surfactant. Sufficient leaf canopy must be present for uptake and translocation. It takes about 4 weeks after treatment to see the full effect. To protect honey bees, apply only during late evening, night, or early morning when bees are not present.
B. IMIDACLOPRID
(Admire Pro – Soil) 7–14 fl oz 12 30
MODE-OF-ACTION GROUP NUMBER1: 4A
COMMENTS: Efficacy of soil-applied neonicotinoids depends on soil texture. Imidacloprid binds readily to certain soil particles, has low water solubility, and long persistence (months). These characteristics allow it to be very effective in light soils, but ineffective in heavy soils. When the soil is rewetted and plant roots are actively absorbing water, the insecticide is also absorbed by roots. Best when applied in a drip irrigation system; otherwise, French plow the soil, apply as a ground spray, and immediately irrigate. Apply 7 to 14 fl oz/acre in one or two drip irrigation applications. On coarse soils or where the longest period of protection is required, make two applications. Make the first application from bloom through the pea-sized berry stage and the second 21 to 45 days later, keeping in mind the preharvest interval. The full rate of 14 oz/acre is recommended where vigorous vine growth is expected or in warmer growing areas such as the San Joaquin or Sacramento valleys or where mealybug numbers are high. Do not exceed 0.5 lb a.i. of imidacloprid (14 fl oz Admire Pro) /acre per year. Adequate soil moisture is important at the time of application; follow label instructions carefully.
C. CLOTHIANIDIN
(Belay – Soil) 6–12 fl oz 12 30
(Belay – Foliar) 6 fl oz 12 0
MODE-OF-ACTION GROUP NUMBER1: 4A
COMMENTS: Efficacy of soil-applied neonicotinoids depends on soil texture. Clothianidin has low water solubility, medium capacity to bind onto soil particles, and moderate to long persistence (weeks to months). Studies indicate it is effective in light soils. Adequate soil moisture is important at the time of application; follow label instructions carefully.
D. THIAMETHOXAM
(Platinum) 8–17 oz 12 60
MODE-OF-ACTION GROUP NUMBER1: 4A
COMMENTS: Efficacy of soil-applied neonicotinoids depends on soil texture. Thiamethoxam has high water solubility, medium capacity to bind onto soil particles, and short to medium persistence (days to weeks). Studies indicate this is the most effective neonicotinoid for heavy soils. Adequate soil moisture is important at the time of application; follow label instructions carefully.
E. DINOTEFURAN
(Venom – Soil) 6 oz 12 28
MODE-OF-ACTION GROUP NUMBER1: 4A
COMMENTS: Efficacy of soil-applied neonicotinoids depends on soil texture. Dinotefuran has very high water solubility, low capacity to bind onto soil particles, and short to moderate persistence (days to weeks). Studies indicate it is moderately effective in heavy soils. Adequate soil moisture is important at the time of application; follow label instructions carefully.
SUMMER
(To obtain clean fruit and to avoid spreading the pest at harvest or by premature leaf drop)
A. IMIDACLOPRID
(Admire Pro – Soil) 7–14 fl oz 12 30
MODE-OF-ACTION GROUP NUMBER1: 4A
COMMENTS: If two applications are required because of coarse soils or where the longest period of protection is required, make the second application 21 to 45 days after the bloom application. Apply 7 to 14 fl oz/acre; the full rate of 14 oz/acre is recommended where vigorous vine growth is expected; in warmer growing areas such as the Coachella, San Joaquin, or Sacramento valleys; or where mealybug numbers are high. Do not exceed 0.5 lb a.i. of imidacloprid (14 fl oz Admire Pro) /acre per year. Adequate soil moisture is important at the time of application; follow label instructions carefully. Use allowed under a 24(c) registration.
B. BUPROFEZIN
(Applaud) 12–24 oz 12 30
MODE-OF-ACTION GROUP NUMBER1: 16
COMMENTS: An insect growth regulator. Buprofezin targets early-stage nymphs on the vine that are exposed and still moving around before they settle under the bark to feed. Good coverage is essential. Do not tank mix. Most effective when applied during peak crawler emergence in the spring (typically late April–early May in the lower San Joaquin Valley and through June in the North Coast region). Buprofezin may harm the mealybug destroyer (Cryptolaemus montrouzieri) when applied during the summer.
C. CLOTHIANIDIN
(Belay – Soil) 6–12 fl oz 12 30
(Belay – Foliar) 6 fl oz 12 0
MODE-OF-ACTION GROUP NUMBER1: 4A
COMMENTS: Efficacy of soil-applied neonicotinoids depends on soil texture. Clothianidin has low water solubility, medium capacity to bind onto soil particles, and moderate to long persistence (weeks to months). Studies indicate it is effective in light soils. Adequate soil moisture is important at the time of application; follow label instructions carefully.
D. THIAMETHOXAM
(Platinum) 8–17 oz 12 60
MODE-OF-ACTION GROUP NUMBER1: 4A
COMMENTS: Efficacy of soil-applied neonicotinoids depends on soil texture. Thiamethoxam has high water solubility, medium capacity to bind onto soil particles, and short to medium persistence (days to weeks). Studies indicate this is the most effective neonicotinoid for heavy soils. Adequate soil moisture is important at the time of application; follow label instructions carefully.
E. DINOTEFURAN
(Venom – Soil) 5–7.5 oz 12 28
MODE-OF-ACTION GROUP NUMBER1: 4A
COMMENTS: Efficacy of soil-applied neonicotinoids depends on soil texture. Dinotefuran has very high water solubility, low capacity to bind onto soil particles, and short to moderate persistence (days to weeks). Studies indicate it is moderately effective in heavy soils. Adequate soil moisture is important at the time of application; follow label instructions carefully.
F. ACETAMIPRID
(Assail 30SG) 2.5–5.3 oz 12 3
(Assail 70WP) 1.1–2.3 oz 12 3
MODE-OF-ACTION GROUP NUMBER1: 4A
COMMENTS: To protect honey bees, apply only during late evening, night, or early morning when bees are not present.
POSTHARVEST
A. SPIROTETRAMAT
(Movento) 6–8 fl oz 24 7
MODE-OF-ACTION GROUP NUMBER1: 23
COMMENTS: A foliar insecticide that is absorbed by the leaves and moves systemically in the phloem and xylem. Use with a non-ionic surfactant. Sufficient leaf canopy must be present for uptake and translocation. It takes about 4 weeks after treatment to see the full effect. To protect honey bees, apply only during late evening, night, or early morning when bees are not present.
B. CHLORPYRIFOS*
(Lorsban Advanced) Label rates 24 NA
MODE-OF-ACTION GROUP NUMBER1: 1B
COMMENTS: Apply in a minimum of 150 gal water/acre. Treat infested vineyards immediately after harvest to minimize the movement of live mealybugs. Use allowed under a Special Local Needs registration (SLN CA-080009). Growers may apply this material under SLN CA-080009 or under SLN CA-080010 but not both. Avoid drift and runoff into surface waters. Certain formulations emit high amounts of volatile organic compounds (VOCs); use low-VOC formulations. Regulations affect use for the San Joaquin Valley from May 1 to October 31, 2019. Additional application restrictions may apply; for more information on current California permit restrictions, see the Department of Pesticide Regulation’s Chlorpyrifos Interim Recommended Permit Conditions.
** Apply with enough water to provide complete coverage.
Restricted entry interval (R.E.I.) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (P.H.I.) is the number of days from treatment to harvest. In some cases the R.E.I. exceeds the P.H.I. The longer of two intervals is the minimum time that must elapse before harvest.
* Permit required from county agricultural commissioner for purchase or use.
1 Rotate chemicals with a different mode-of-action Group number, and do not use products with the same mode-of-action Group number more than twice per season to help prevent the development of resistance. For example, the organophosphates have a Group number of 1B; chemicals with a 1B Group number should be alternated with chemicals that have a Group number other than 1B. Mode-of-action group numbers are assigned by IRAC (Insecticide Resistance Action Committee). For additional information, see their Web site at http://www.irac-online.org/.
NA Not applicable.
# Acceptable for use on organically grown produce.

IMPORTANT LINKS

PUBLICATION

UC IPM Pest Management Guidelines: Grape
UC ANR Publication 3448

Insects and Mites

L. G. Varela, UC IPM Program and UC Cooperative Extension, Sonoma County
D. R. Haviland, UC IPM Program and UC Cooperative Extension, Kern County
W. J. Bentley, UC IPM Program, Kearney Agricultural Research Center, Parlier
F. G. Zalom, Entomology, UC Davis
L. J. Bettiga, UC Cooperative Extension, Monterey County
R. J. Smith, UC Cooperative Extension, Sonoma County
K. M. Daane, Kearney Agricultural Research Center, Parlier

Acknowledgment for contributions to Insects and Mites:

M. C. Battany, UC Cooperative Extension, San Luis Obispo County
J. Granett, Entomology, UC Davis
P. A. Phillips, UC IPM Program, Ventura County
A. H. Purcell, Environmental Science, Policy and Management, UC Berkeley

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Plant Health August 2013

Mealybugs and Systemic Insecticides
By Amy L. Willmott and Raymond A. Cloyd

Mealybugs are one of the most destructive insect pests of greenhouse and interior plantscape environments. One of the commonly encountered mealybug species of greenhouses is the citrus mealybug, Planococcus citri (Figure 1). Citrus mealybugs are considered phloem-feeders like aphids, whiteflies, leafhoppers and soft scales. The phloem is the food-conducting tissue of plants. Citrus mealybugs withdraw plant fluids directly from the phloem sieve tubes using their stylet-like mouthparts.

Mealybugs can cause both direct and indirect damage to plants. Direct damage occurs during feeding on plant vascular tissues, which results in plant stunting, wilting, yellowing of leaves, leaf drop and possibly plant death. Indirect damage is associated with the excretion of honeydew, a clear sticky liquid that is an ideal growing medium for black sooty mold fungi, which can reduce the ability of plants to photosynthesize. Mealybug populations are difficult to mitigate with insecticides because they spend some or all of their life cycle in inaccessible areas on plants such as leaf junctures and on the underside of leaves, which may be extremely difficult to reach with sprays of contact insecticides especially when plants have complex plant architectures (many branches and leaves) (Figure 2).

Despite this, insecticides, including those with contact and also systemic activity, are still primarily used to control or regulate citrus mealybug populations. Systemic insecticides are applied preventatively to the growing medium as a drench or granule for uptake or absorption via the roots, and then translocated throughout the plant through the vascular system. Most systemic insecticides are translocated through the plant via the transpiration stream, which is the movement of water through the plant by means of the xylem or water-conducting tissues. They are primarily active on xylem and phloem-feeding insect pests with piercing-sucking mouthparts such as aphids, whiteflies, mealybugs, leafhoppers, planthoppers and soft scales, as these insect pests feed exclusively within the xylem vessel elements or phloem sieve tubes. During the feeding process, these insects withdraw and ingest lethal concentrations of the systemic insecticide’s active ingredient and are subsequently killed.

There are a number of advantages associated with using drench or granular applications of systemic insecticides compared to foliar sprays. For instance, drench applications reduce exposure to workers and natural enemies such as parasitoids and predators. In addition, systemic insecticides are translocated through the plant vascular system including the xylem and phloem, protecting growth that would have been missed when applying a contact insecticide, as well as any new growth following an application. This may provide protection for extended periods of time. Furthermore, applying systemic insecticides, as drenches or granules, reduces the amount of material lost due to evaporation, light degradation and irrigation (wash-off).

Factors that may impact the effectiveness of systemic insecticides in regulating insect pest populations include plant species, plant age, water solubility, growing medium type, transpiration rate (movement of water through the xylem) and insect pest feeding behavior. It is the last factor, insect pest feeding behavior, that we wanted to investigate and determine if this actually influences the efficacy of systemic insecticides. In greenhouse production systems, systemic insecticides are commonly used to control or regulate populations of phloem-feeding insects such as the citrus mealybug. However, minimal information is available on the actual efficacy of systemic insecticides against citrus mealybugs. Therefore, we conducted a number of experiments to assess the effectiveness of systemic insecticides against the citrus mealybug and to also quantify the feeding location (plant stem, leaf top and leaf bottom) on coleus (Solenstemon scutellarioides) plants.

For the sake of brevity, all four experiments were conducted in a greenhouse at Kansas State University (Manhattan, Kan.). We evaluated the following systemic insecticides: azadirachtin (Azatrol), spirotetramat (Kontos), imidacloprid (Marathon II), dinotefuran (Safari) and thiamethoxam (Flagship). Both azadirachtin and spirotetramat were applied before (preventatively) and after (curatively) coleus plants were infested with citrus mealybugs whereas the neonicotinoids (imidacloprid, dinotefuran and thiamethoxam) were applied preventatively and then the residual activity was recorded for seven weeks. In all the experiments, labeled rates were used and citrus mealybug feeding location (plant stem, leaf top and leaf bottom) was recorded.

Results and Discussion

In both experiments associated with azadirachtin and spirotetramat, the level of citrus mealybug mortality for both green and red coleus was less than 30 percent across all three weeks as either preventative or curative treatments. Both active ingredients have very low water solubilities (azadirachtin=0.50 ppm and spirotetramat=29 ppm), which likely influenced their movement throughout the plant and thus ability to control or regulate citrus mealybug populations during the three-week period. Most mealybugs were located on the plant stem for the green coleus, and both the plant stem and leaf bottom for the red coleus (Figures 3 and 4). For the experiments with neonicotinoid insecticides imidacloprid, dinotefuran and thiamethoxam, citrus mealybug mortality was highest 21 and 28 days after treatment for all three systemic insecticides with thiamethoxam and dinotefuran providing the highest mortality (more than 60 percent); however, mortality declined substantially 35, 42 and 49 days after treatment (Figure 5). Both thiamethoxam and dinotefuran were numerically higher in regards to citrus mealybug mortality than imidacloprid 21 days after treatment, which is likely related to the differences in water solubility among the three systemic insecticides: thiamethoxam (4,100 ppm), dinotefuran (39,000 ppm) and imidacloprid (510 ppm). Most of the citrus mealybugs were located on the plant stem for all the treatments (Figure 6).

So, why were the systemic insecticides not effective against the citrus mealybugs? First, the lack of effective control may be associated with the feeding behavior of the insect as citrus mealybugs tend to congregate on plant stems, which may allow them to avoid ingesting lethal concentrations of the active ingredient. Furthermore, it is possible that systemic insecticides are primarily located within the xylem of stems where the main transport within the plant occurs. In addition, it may be that the leaves act as a sink for the insecticide, and once the insecticide reaches the sink, then there is movement from the xylem to the phloem, thereby affecting phloem-feeders more effectively. In fact, the phloem-feeders may avoid higher doses because the movement of the insecticide between the xylem and phloem is not as pronounced compared to the insecticide residues at the sink area.

Second, citrus mealybugs may be less susceptible to systemic insecticides than aphids and whiteflies, which could be affiliated with their feeding behavior that is different in the number and length of time of intracellular punctures and stylet mobility during the phloem-searching process. This may impact the ability of systemic insecticides to provide sufficient control or regulation of citrus mealybug populations. Also, females that are producing eggs or offspring (young) do not feed, and with an extended egg-laying period of at least four weeks, the female may survive and continue to lay eggs beyond the residual activity of the systemic insecticide. Another important factor to consider that may impact the effectiveness of systemic insecticides, although not related to feeding behavior, is the plant growth stage. For example, if plants are in the reproductive phase or flowering then this may influence the rate of transpiration. Plants typically transpire less during flowering, which would negatively affect the movement or translocation of the systemic insecticides within the plant tissues. Therefore, reduced transpiration would lead to less absorption of the active ingredient by the roots, thus less active ingredient would be translocated throughout the plant, resulting in less control or regulation of citrus mealybug populations.

It has been suggested that timing of application may influence the efficacy of systemic insecticides, as applications conducted during late fall through winter may be less effective than applications made in spring through summer. This is due to the higher amount of sunlight and thus light intensity, and longer days, which could affect the transpiration rate. For instance, systemic insecticides have been demonstrated to be less effective when applied in January or February compared to applications made March through August. In our study, preventative treatments of azadirachtin and spirotetramat were applied in March whereas curative treatments were applied in May. The preventative treatments (March-April) resulted in less than 20 percent mortality, and the curative treatments (May-June) resulted in less than 30 percent mortality. As such, there were no differences in citrus mealybug mortality between azadirachtin and spirotetramat. The experiment with the neonicotinoid insecticides was conducted from July through September, with the highest citrus mealybug mortality (77 percent) provided by thiamethoxam. In previous research, we have shown that light intensity may influence the uptake of systemic insecticides thus affecting their ability to control or regulate populations of phloem-feeding insect pests including whiteflies and mealybugs.

In conclusion, feeding behavior may impact the effectiveness of systemic insecticides in regulating populations of the citrus mealybug. In our study, most citrus mealybugs were located on the plant stem and were alive with females laying eggs, which indicates that citrus mealybug may not be ingesting lethal concentrations at this location or an insufficient concentration of active ingredient is being translocated through the stem. Further research is being conducted to evaluate the effect of systemic insecticides on the citrus mealybug and quantify the concentration of active ingredient in plant tissues where citrus mealybugs tend to feed.

Amy L. Willmott and Raymond A. Cloyd

Amy L. Willmott is research associate and Raymond A. Cloyd is professor and extension specialist in the department of entomology at Kansas State University. Cloyd can be reached at

Mealybugs, also called “woolly aphids”, include many species with a wide range of host plants. They are a type of soft scale coated with a woolly, waxy secretion that provides protection and decreases the effectiveness of contact insecticides. Like many other soft-bodied insects, mealybugs damage plants by feeding on sap and other cell contents.

How To Identify A Mealybug Infestation:

  • The plant is covered with small, white-to-grey insects with a cottony/wooly covering clustering close to the soil or near the growing tips.
  • Honeydew is present on plant surfaces, with or without sooty mold.
  • Infested plants may have a distorted stem and/or new growth.
  • Reduced plant vigor and health overall after mealybugs have been identified.
  • Ant presence near new growth harvesting honeydew.

Controlling Mealybugs: Mealybugs and other types of soft scale can be difficult to control once populations have ballooned to large numbers. Small populations and immature stages of mealybugs are usually easy to control with regular monitoring and treatment.

  • Spray Insecticidal Soap directly onto visible mealybugs for control. The insecticidal soap serves as a contact insecticide and does not have residual effects, so repeated applications are necessary for continued control.
  • Neem Oil can be applied directly to active infestations. It will kill all stages of mealybugs on contact. Use caution applying neem oil when pollinators are present.
  • Horticultural Oil applications will kill overwintering eggs and smother immature and adult mealybugs when temperatures are Generalist Predators can be introduced early in the growing season to help control mealybugs. Generalists include Green Lacewing, Ladybugs and Assassin Bugs.
  • Early season releases of Mealybug Parasites help limit population growth and control mealybugs in low numbers. These work well for vine mealybug control when combined with Cryptolaemus.
  • Mealybug Destroyers (Cryptolaemus montrozeuri) can be released to control severe mealybug infestations. They are dark brown ladybugs with orange heads whose preferred food sources are the various life stages of mealybugs.
  • If mealybug issues persist after Beneficial Insects have been released, use a Beauveria bassiana product like Mycotrol WPO so that the beneficials are not harmed.

Mealybugs: White Residue On Plant’s Leaves

Houseplants can be found in many homes and many houseplants are pretty, yet easy to care for plants. Unfortunately, due to the enclosed environment that a houseplant is normally found in, houseplants are susceptible to pests. One of those pests is mealybugs.

Does My Houseplant Have Mealybugs?

Mealybugs will commonly leave a white residue on a plant’s leaves that resembles cotton. You will find this residue mostly on the stems and leaves. This residue is either the egg sacs of the mealybugs or the pests themselves.

You may also find that the plant has a sticky residue on it. This is honeydew and is secreted by the mealybugs. It can also attract ants.

Mealybugs look like small,

flat oval white spots on plant leaves. They are also fuzzy or powdery looking.

How Do Mealybugs Hurt My Houseplant?

Besides the unsightly white residue and spots on plants’ leaves, mealybugs will literally suck the life out of your houseplant. When they reach maturity, a mealybug will insert a sucking mouth into the flesh of your houseplant. One mealybug will not hurt your plant, but they multiply quickly and if a plant is badly affected, the mealybugs may overwhelm the plant.

Mealybug Home Pest Control

If you have found the white residue on plant’s leaves that indicates a mealybug infestation, immediately isolate the plant. One mealybug home pest control is to scrape away any white residue and spots on plants leaves that you can find. Then, using a solution of one part alcohol to three parts water with some dish soap (without bleach) mixed in, wash down the entire plant. Let the plant sit for a few days and repeat the process.

Another mealybug home pest control is to apply neem oil or a pesticide to the plant. You will most likely need several treatments.

Mealybugs are damaging and difficult to eliminate, but it can be done with prompt attention to the signs of a mealybug infestation.

If you are a houseplant owner maybe you have experienced white sticky stuff on plants or sticky residue on plant leaves.

There are many causes for wet or sticky plants and these incidents can present quite a hassle for any plant owner.

What causes it and how do you handle a plant with sticky leaves? Read on…

You often find leaves on houseplants with sticky stuff covering them like the Ficus

Question: My houseplant has sticky leaves! It’s the only way to describe the foliage. No matter what I try the cure never seems to happen.

Should I get rid of the fica plant? Do you know if it’s a disease or know what causes the sticky plant leaves and the cure? April, Oregon

Answer: April, a sticky substance on the leaves is one houseplant problem that isn’t unique.

Since you did not mention the indoor houseplant you’re experiencing the sticky issue on, here’s a general overview of the problem.

After you’ve brought your new plant home and its gone through the:

  • Acclimation process of leaf drop
  • Adjusting to a new watering schedule
  • And happy with its new indoor life

… it seems to happen. A sticky substance on the leaves.

One day on the way to grab your breakfast you notice the area around your indoor plant is tacky or sticky, a sticky couch, sticky floors, and the leaves are sticky too.

You step back, scratch your head and ask a few questions…

  • Did the kids spill a soft drink?
  • What caused it?
  • Do I have enough time to clean it up?

Cause of Sticky on House Plant Leaves

The cause of the sticky leaf is normally scale insects on the plant. Scale insects feed and suck sap (the juices) out of houseplants.

The sticky residue on the leaves and floor is what they secrete and is a sticky substance called honeydw or sticky honeydew.

Too often people only look at the top leaves. Check plants by looking at the underside of the leaves and on the stems for slight bumps of tan, black or brown color with a waxy coating.

You’ll find infested plants with scale insects or cottony masses of mealybugs hiding in out of the way places and out of sight where they can be left alone.

Sticky Leaves Treatment – Controlling Scale

Generally controlling scale insects isn’t a big problem. Scale “breathes” through their “armor.” The easiest way to kill the scale is by suffocation.

There are several natural methods to get rid of the scale insects on plants indoors.

In the early stages with a light infestation:

  • Mix 1 teaspoon of DAWN dish detergent into 1 quart of warm water
  • Dip a cotton swab into the dish detergent / warm water mixture
  • Wipe the area down completely

also

For large infestations place the mixture into a spray bottle and spray the entire plant with the mixture, coat the infested areas completely.

The dish detergent “clogs” or disrupts the plant scale insects ability to breathe.

Other additions to the spray mixture include:

  • A good plant insecticidal soap solution. The most popular plant soap goes by the name “Safer Soap” and works well if the infestation of scale isn’t extensive.
  • Another “safe option” is to try Neem oil spray for plants. Neem oil is a great overall natural product that can take also get rid of spider mites and even fleas on pets.
  • Add a safe horticultural oil will do the trick. A word or warning – When applying any chemical, indoors or outdoors, do it carefully and follow the label directions exactly.

Before attempting to handle the pest issue check with your local nursery or garden center – and remember … FOLLOW THE LABEL.

NOTE: On indoor plants, I would use neem oil or an insecticidal soap. The horticultural oil is better on outdoor plants.

Outdoors the sticky residue usually is accompanied with sooty mold. As mentioned above horticultural oil, neem oil and insecticidal soap can all be used outdoors.

However, do not apply when temperatures are over 85° degrees Fahrenheit and beware these controls will also kill natural predators.

Systemic Control

Pest control with a spray indoors, especially in public areas adds an additional risk. Many interior plantscaping companies control plant scale and other pest problems with systemic insecticide chemicals.

Systemics work through the root system. The chemical for control is normally applied to the soil or buried in the soil where the plant absorbs the chemical through the root system and distributes the chemical throughout the plant.

As the scale insect, mealybug, spider mite, and other pests (sticky bugs) feast on sucking the plant’s juices out they take the chemical into their bodies which kills them. The systemic process take time – six to eight weeks is not uncommon.

The systemic process is used primarily on large trees like ficus found in hotels and malls.

Our Recommended Natural Pest Control Solutions For the Home and Garden

  • Neem Plant Insecticide – Details on Neem Oil Pest Spray
  • Diatomaceous Earth – Food Grade – More on using DE here
  • Bacillus thuringiensis Bt
  • Insecticidal soap – More on insecticidal soap here
  • Beneficial Insects – Ladybugs, Predatory Mites and Green Lacewing

For more info on these recommended products, read our detailed review here.

How to Clean Up the Sticky Liquid Stuff

Cleaning the stucky stuff off furniture versus the floor can get a little tricky.

You first must remember to pick up and clean up as much of the sugary sticky honeydew goo as you can.

Start by using VERY WARM water, apply to the area with a damp cloth or mop rinse frequently in HOT clean water.

Some professionals recommend using Murphy’s Oil Soap and others rubbing alcohol and swabbing the area with a soft cloth.

Make sure you test your cleaning potion on an “inconspicuous area” before you start pouring it on. You could discolor material or strip off the furniture finish.

For good plant health the most important thing to remember is maintenance – once you have control, maintain it by regular scouting of your plants for pests and plant diseases.

Growers always keep on the lookout for ants. Ants are great farmers and farm the scale insects and aphids for the honeydew they produce.

Finding potential problems early helps prevent really big problems you’ll have to deal with later, not to mention the sticky floors and furniture.

The leaves on my houseplant are covered with a sticky sap. There are also small “bumps” on the stems. What is the pro

The houseplant may be infested with scale insects. These small, inconspicuous insects are covered with shell-like coverings. They attach themselves to stems or leaves and suck sap from the plants. As they feed, the scale insects excrete a sweet, sticky substance called honeydew. The honeydew accumulates on the plant’s lower foliage, furniture, carpeting, or other objects beneath the infested plant.

The life cycle of scale insects consists of the egg, nymph, and adult stages. Eggs are laid below the scale coverings of the adult females. When the eggs hatch, the nymphs crawl from underneath their mother’s scale and move a short distance to their own feeding site. The newly emerged nymphs are also called crawlers. At their new location, the nymphs insert their slender stylets (mouthparts) into the plant and begin sucking sap. The covering or shell develops soon after feeding begins. Scale insects remain at these feeding sites the rest of their lives.

A small scale infestation causes little harm to healthy houseplants. However, a heavy scale infestation may result in poor, stunted growth. In severe cases, death of infested plants is possible.

Scale insects are difficult to control. Systemic insecticides are generally ineffective. The shell-like covering protects the scale from contact insecticides. The only time scale insects are vulnerable to contact insecticides is during the crawler stage. Since scale insects on houseplants don’t reproduce at a specific time, scale-infested plants will need to be sprayed with insecticidal soap or other houseplant insecticide every 7 to 10 days until the infestation is eliminated. Small infestations can be controlled by individually scraping off the scales or by dabbing each scale with an alcohol-soaked cotton swab. It’s often best to discard houseplants that are heavily infested with scale as control is nearly impossible and the insects could spread to other houseplants.

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