While powdery mildews don’t kill their hosts, they sure do a number on them. And that is particularly true for powdery mildew of apples and crabapples, Podosphaera leucotricha.

The apple powdery mildew attacks both cultivated and wild apples and crabapples. And it occurs in the all regions of the world that produce apples!

Powdery mildews get their name from the white spores that are produced by the mycelia (fungal threads). The disease on apples attacks virtually every stage of the plant – buds, blossoms, new shoots, leaves, and fruit.

The disease can be severe enough that no fruit form.

While fungicides are the standard treatments, there are some cultural practices that can help control this disease.

Unlike most fungal infections, apple powdery mildew spores do not require moisture to germinate. Therefore, this infection is known as the “dry weather disease.”

Read on as we at Gardener’s Path walk you through the steps you take to diagnose and treat powdery mildew infection on your apple or crabapple tree.

Contents

Symptoms of Primary Infections

If your tree is infected, the first thing you will notice is a delay of up to four days in the opening of the infected buds in the spring. These buds are covered with spores.

Next, the leaves and blossoms become covered with the fungal spores as they emerge from their buds. The spores look like a light gray or white powder, and the infected leaves curl upward.

Both sides of the leaves and tree shoots will be covered with this powder.

The flowers develop abnormally, are usually greenish-white, and don’t produce fruit.

An Infection That Won’t Stop

These spores are easily blown by the wind and cause secondary infections on new shoots, leaves, and fruit.

As long as the shoots continue growing, the leaves and shoots can continue to become infected.

The infections typically occur at night at 65 to 80 F when the relative humidity is greater than 70%. While this sounds really high, it is common on the lower leaf surface.

A white fuzzy coating on your apple tree blooms, leaves, and branches can mean one thing – the Podosphaera leucotricha fungs, or apple powdery mildew.

The disease on the leaves occurs first on the bottoms and may appear like chlorotic spots on the top of the leaves.

As time passes, the tissues that are infected develop the classic silver-gray powdery mildew appearance.

Fruit that is infected will come down with discoloration and netlike reddish brown colors. It may also be distorted and/or dwarfed.

High levels of powdery mildew at the end of the growing season can damage the tree in two ways. First, it can increase the number of infected buds, so you will have a high level of infection next spring. And second, it can inhibit the formation of flower buds, so that there will be fewer or no fruit produced the following season.

And if that isn’t bad enough, a tree that is heavily infected with powdery mildew can become susceptible to additional types of infections.

Cultural Controls

You should prune any shoots that appear white in the early spring, so they won’t spread spores.

Pruning and destroying infected areas is one basic method of control. Don’t forget to disinfect your pruning shears between trees and after you are done for the day.

Be sure and disinfect your pruning shears afterwards, and destroy all the infected plant parts, so the disease won’t spread.

Avoid the excessive use of fertilizer, especially in the late summer. This will prevent succulent new tissue from growing, which is easily infected by the fungus.

Another thing you can do to protect your tree is to plant it in a sunny area, since excessive shade, high humidity, and poor circulation all increase the chances of infection.

Fungicides

Since this is such a difficult disease to control, and it is critical to eliminate the spores that will keep infecting your tree, you may choose to apply fungicides. Be sure and choose ones that are labeled specifically for fruit trees.

You have a choice of low toxicity fungicides like horticultural oils. These include jojoba oil, neem oil, and brand name spray oils designed for fruit trees.

Classic fungicides that are used against apple scab, such as sterol inhibitors, are highly effective at controlling powdery mildew. These include myclobutanil and fenbuconazole.
Since the fungus overwinters inside buds, you should start treating your tree early in the season before the blossoms start to show a pinkish color.

The failure to spray before the blooms opens is one of the most common mistakes made in controlling this disease according to the American Phytopathological Society.

Be sure and repeat the sprays at 2-3 week intervals until the new shoots stop growing. That could mean as many as 18 sprays if your cultivar is highly susceptible!

Also be sure to continue spraying even if the weather becomes dry. Unlike most other foliar pathogens, apple powdery mildew continues its growth and spore production in dry weather.

Faithfully applying the fungicides will reduce the need for future applications.

Prevention

You can also spray sulfur fungicides before the symptoms appear.

Be careful with sulfur. You can harm the plant if you apply it within two weeks of a fungicide or if the temperatures are greater than 90 F.

This class of fungicides includes the classic Bordeaux mixture of copper sulfate and lime. This combination is highly effective at preventing powdery mildew and is certified organic. You can buy a pre-packaged mixture designed for small gardens.

These apple trees have had their trunk coated with Bordeaux mixture, a copper sulfate and calcium oxide in water. This helps to prevent a powdery mildew infection. Though fairly toxic, this method of prevention is considered organic.

The ultimate prevention technique is to plant resistant varieties! Some of the most popular cultivars are the most susceptible – Granny Smith, Jonathan, and Rome for example.

Some of the more common resistant cultivars include:

  • Braeburn
  • Britegold
  • Delicious
  • Enterprise
  • Fuji
  • Gala
  • Jonafree
  • Nittany
  • Winesap

Apple Crop Risk

Although apple powdery mildew will not technically kill your crop, it can debilitate the tree to such an extent that it could be unable to produce any fruit.

This disease is widespread on wild and cultivated apples and crabapples in every part of the world in which they are grown.

Therefore, it is critical to know the symptoms of this mildew, so you can be ready to take action as soon as you see infected tissue.

You will need to spray with some sort of fungicide – sulfur, horticultural oils, or sterol inhibiting fungicides. A strict spray schedule may help save your tree from this aggressive pathogen.

Have you successfully fought off powdery mildew on your apple or crabapple tree? Let us know how your battle went in the comments.

And if you’re still trying to identify a specific disease on your apple tree(s) then some of these guides may be of assistance:

  • How to Identify and Control Sooty Blotch and Flyspeck on Apples
  • How to Identify, Prevent, and Control Cedar Apple Rust
  • How to Identify and Prevent Southern Blight on Apple Trees

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About Helga George, PhD

One of Helga George’s greatest childhood joys was reading about rare and greenhouse plants that would not grow in Delaware. Now that she lives near Santa Barbara, California, she is delighted that many of these grow right outside! Fascinated by the knowledge that plants make chemicals to defend themselves, Helga embarked on further academic study and obtained two degrees, studying plant diseases as a plant pathology major. She holds a BS in agriculture from Cornell University, and an MS from the University of Massachusetts Amherst. Helga then returned to Cornell to obtain a PhD, studying one of the model systems of plant defense. She transitioned to full-time writing in 2009.

What to do with current apple powdery mildew infection

Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.

Apple powdery mildew is caused by the fungus Podosphaera leucotricha. This fungus grows as a white mass on new terminal growth of trees, eventually enveloping shoot tips. These symptoms can result in loss of vigor and potential effects on return bloom and yield of bearing trees and stunted growth of nonbearing trees. In addition, powdery mildew infection of fruit can cause russeting if the disease is not controlled before fruit are present. The powdery mildew fungus is unique in that it can infect trees in the absence of wetting from rain or dew.

Apple powdery mildew is effectively controlled by sterol-inhibitor (SI) fungicides or strobilurin fungicides. However, because of resistance in the apple scab fungus to these classes of fungicides, there has been a sharp cutback on use of these materials in Michigan in 2010. The result – powdery mildew infection is fairly common this year, with infection as much as 30-50 percent in some orchards.
The peak risk for mildew infection is the period right after petal fall, which coincides with rapid leaf growth of trees. This timing is likely when the initial mildew infections occurred this year in Michigan. Since only new unfolding leaves are susceptible to infection, and since infection risk ends when the trees set terminal buds, the questions of the day are (1) “What should be done, if anything, in orchards with current heavy mildew infection?” (2) “What should be done on trees with no fruit?”

Besides the impact of mildew on the current season, buildup of mildew infection will typically ensure the presence of plenty of inoculum for next season. Thus, control is probably warranted if trees are still actively growing. This is particularly important on young trees, where active growth continues, and the consequences of mildew infection are more severe.

Here are some suggestions for mildew control in orchards exhibiting infection currently. We consulted with Dr. David Rosenberger from Cornell University as well to determine possible fungicides to utilize at this time. On nonbearing trees or trees where the fruit crop has been lost to frost, further mildew spread can be effectively slowed with sulfur applications at 10 lbs per acre applied every two weeks. A reduced amount of sulfur should be used on bearing trees to avoid scorching the fruit. This would be the cheapest option to arrest further mildew infection.

On young trees, it is likely worth the investment in an SI, such as Rally, to help limit the inoculum carryover to next year. The new SI fungicide Topguard that was recently registered is an excellent mildewcide and could be used, if it is available. There is some concern with possible development of resistance to SI’s in the mildew fungus in New York. We don’t have any evidence currently to suspect a resistance problem in Michigan. Flint and Sovran, Bayleton, Topsin M, and Pristine are also effective fungicides for powdery mildew control. EBDC’s and Captan are not effective, and may kill other fungi that can inhibit powdery mildew somewhat, making the problem worse.

The powdery mildew fungus overwinters in infected buds. Winter temperatures below -5°F can eliminate some of this inoculum as infected buds can be killed following exposure to these low temperatures (killing the fungus with it). However, according to Dave Rosenberger, the only locations that can really count on cold temperatures taking care of powdery mildew inoculum are locations such as the Champlain Valley in Vermont, which can get temperatures as low as -40°F. Thus, the more mildew can be controlled now; the less chance there is for extensive inoculum to be present next year.


Photo 1. Here’s a single leaf showing an
advanced level of powdery mildew.


Photo 2. Powdery mildew affecting a
growing apple shoot.

Apple woolly aphid Erisoma lanigerum

Look for

Long white, or occasionally blue-grey, waxy residues which look like cotton wool appear on the bark and branches especially around old pruning wounds. There may also be droplets of sticky, sugary honeydew on the bark which may become infected with black sooty mould. Cankers may also be present on aphid infested areas.

Plants affected

  • Apple, pear, prunus, crab apple, pyracantha, cotoneaster, elm, hawthorn and mountain ash trees.

About Apple woolly aphid

  • Adult aphids are up to 2mm long and elliptical in shape. They are pinkish-brown but their waxy coating gives them a white, woolly appearance.
  • This species does not overwinter as eggs but as young, under loose bark, or in cracks in bark or surface roots.
  • Young emerge in spring to re-establish the colony.
  • Aphids can give birth to as many as five live young a day so rapidly produce large colonies.
  • After a few generations, winged adults develop and move to new trees.
  • Colonies will develop around cracks and wounds in trees, as well as new shoots.
  • Feeding by apple woolly aphids will cause knobbly galls to form making the tree more susceptible to canker and other infections.
  • Aphids feed on plant sap and excrete plant sugars as honeydew.
  • Honeydew often covers the leaves of a plant and then becomes infested with unsightly black sooty moulds.

Treatment

Chemical

Products containing the following chemical ingredients are all effective on Apple woolly aphid

  • Pyrethroids and Pyrethrin

Note: It is important to read manufacturer’s instructions for use and the associated safety data information before applying chemical treatments.

Organic

  • Check tree shoots and bark regularly for signs of woolly aphid.
  • Scrub areas within easy reach with a brush and a bucket of soapy water.
  • Spray infested areas with a firm jet of water to help reduce aphid numbers.
  • Spray with natural fatty acids such as an insecticidal soap.
  • The parasitic wasp Aphelinus mali will attack aphids above ground level.
  • Aphid predators such as ladybirds, aphidoletes, hoverflies, and lacewing larvae can be encouraged by providing suitable overwintering sites and by growing flowers which attract them.
  • Regularly check plants for signs of infestation and deal with them as soon as they appear.
  • Encourage natural enemies like ladybirds, hoverflies and lacewings to become established in the garden by planting daisy-like flowers, yellow flowers and in particular, the poached egg plant Limnanthes douglasii.
  • Avoid using broad spectrum insecticides which will kill beneficial insects as well as aphids.
  • Encourage insect-eating birds such as blue tits, by hanging feeders in winter and nest boxes in spring.
  • If planting new apple trees, use rootstocks which are resistant to apple woolly aphid.
  • Paint pruning wounds with a tree coating composition to help prevent infestations establishing.

IDENTIFY AND TREAT WOOLLY APHIDS

IDENTIFYING WOOLLY APHIDS

Woolly Aphids are very easily identified because they have two unusual characteristics. Firstly the white fluffy coating they cover themselves with is very obvious and unusual. Secondly they attack the bark of a tree and not the leaves.

If you take a small twig and scrape off the fluffy coating, underneath you will see the tiny bugs feeding on the sap of the tree. They are brownish and elongated. The fluffy material will start appear in small amounts in spring and become larger as the year progresses – it is not present in winter when the bugs are inactive.

The fluffy material ranges in colour from white to dark grey. If it is dark in colour then you probably have a secondary infection from some other bug at the same time.

If woolly aphids are allowed to progress untreated it will attack the roots at some stage although only digging up the soil around the roots will allow you to see them here.

When the aphids feed on the sap they also release chemicals into the bark and flesh of the tree which results in bumps which can be seen on the surface of the bark. This is the tree trying to cover up and protect the damaged area. These lumps can be damaged by frost in winter and split open making them a primary site for canker to enter the tree in the next spring.

LIFECYCLE OF WOOLLY APHID

Transmission of the disease from one tree to another is primarily by the aphid when it is able to fly – July and August is is the prime time of year for this.

MID SUMMER
The aphids are able to fly at this time of year and they search out other apple trees and plants to start a new infection site.

AUTUMN WINTER
Woolly Aphids overwinter in cracks and crevices on the bark of apple trees. They can also overwinter on the roots underground of affected trees.

SPRING TO SUMMER
Young woolly aphids begin to feed on the sap of the tree and reproduce at an alarmingly quick rate. They weave a woolly fluff around infected areas to protect themselves from birds and other predators. Initially they attack older stems but as the year progresses they move onto new shoots. Infected areas of the bark grow nodules and bumps to protect themselves.

The attack becomes more apparent throughout the year reaching a peak in mid summer time.

DAMAGE CAUSED BY WOOLLY APHIDS

Attacks on the bark leave the tree weakened and open to infestation by other bugs and diseases. The bumps on the bark can often be opened by frost in cold periods making the tree very vulnerable to attack by canker the following year.

PREVENTING WOOLLY APHIDS IN APPLE TREES

There are two main actions you can take to reduce the likelihood of a woolly aphid attack. The first is to buy apple trees on rootstocks which are resistant to woolly aphid attack. The most resistant, commonly available rootstock is MM106. The second preventative measure is correct pruning methods and avoiding damage to the bark of your trees. Bad pruning techniques and damage to the bark of a tree provide ideal sites for infection by woolly aphids.

TREATING AND GETTING RID OF WOOLLY APHIDS

There are chemical pesticides for treating woolly aphids and in general they work well. The rules and regulations concerning chemicals for the amateur gardener change constantly so we won’t recommend a specific pesticide here but enter “pesticide for woolly aphids” in your web browser and several results will come up. A word of warning though, follow the instructions carefully and don’t spray chemical treatments for woolly aphids outside of the recommended times, some of the chemicals can cause significant damage to helpful predators.

Organic methods also work well as long as the infection is predominantly above ground. To increase your chances of organic methods working, early identification of the pest in spring is vital. As soon as the woolly aphids are indentified spray them with a strong jet of water from a hosepipe or similar. this will remove a large number of them.

Remove any remaining by using a small brush and some soapy water. Keep an eye on infected trees throughout the year and repeat the treatment whenever you see any more fluffy areas reappear. If any stems or branches are particularly badly infected then prune them out.

Need help with what to do in your garden?

Q What is woolly aphid?

A This aphid (Eriosoma lanigerum) arrived in Britain in the 18th century and is now very common. Woolly aphids feed on apples and ornamentals that are closely related, such as crab apples, chaenomeles, cotoneaster and pyracantha.

Caption: Woolly aphids are covered in fluff which helps to protect them

Q How do I recognise woolly aphid?

A You will not see the small, brown or greyish-purple aphids, but rather their woolly protective coating which is white and waxy. This coating looks rather like a fungus, especially when the woolly aphids cluster together in large numbers.

Woolly aphids feed on sap and are attracted to younger, woody shoots and damaged areas such as pruning wounds. Unsightly galls form where aphid colonies have attacked. These can split, letting in diseases such as apple canker.

Woolly aphids don’t attack the roots, but they can infest the base of the trunk.

Q When should I expect to see woolly aphid?

A They overwinter as young aphids. These are not covered by waxy strands, so they are hard to spot. In March and April they become active, and soon breeding colonies covered in a white, woolly coating will be noticeable.

They spread by producing crawling young which find new areas to colonise then produce young. In July winged forms fly off to infest other plants. Breeding stops in autumn when immature aphids seek sites to overwinter.

Q How much of a problem are woolly aphids?

A On a healthy tree, woolly aphid is unlikely to do much damage, though it can harm young trees or those weakened by disease or poor growing conditions However, sticky masses can be a nuisance when harvesting fruit.

Infestations are often kept in check by predators. Both native predators, such as ladybirds, hoverflies and lacewings, and an introduced parasite attack woolly aphids.

The introduced parasite, a tiny wasp Aphelinus mali, now lives wild in southern England and is especially effective during hot, dry years. You can tell that this parasitic wasp is at work in your garden if the wool has been reduced, leaving a shiny, blue-black, naked aphid with a circular hole in its back through which the parasite has made its exit.

Although this parasite is very susceptible to insecticides, it will thrive in an organic garden.

Q How can I control woolly aphid?

A Watch for signs of woolly aphid in the spring. Scrub them off using water with a drop of detergent in it. If you can get rid of the bark colonies before the aphids begin to move on to young shoots in July, it will make spraying unnecessary.

If early control is unsuccessful, spray with Growing Success Fruit and Veg Bug Killer or Provado Ultimate Bug Killer Ready to Use.

APPLE TREE PESTS AND DISEASES

PEST AND DISEASES AFFECTING APPLE TREE LEAVES

CURLED AND DISTORTED LEAVES, BLACK STICKY PATCHES ON LEAVES

This is caused by aphids, tiny little insects which are often first noticed on the underside of new tender leaves. The black sticky is been excreted by the aphids and has been infected by mould. Although unlikely to cause severe damage aphids do need to be controlled in order to ensure a good crop of apples.

Adult aphids on a leaf

SOME LEAVES COVERED IN WHITE POWDER

The white powder (looks like a fine layer of talcum powder) is mould or mildew, the disease is known as powdery mildew.

Infected leaves may be slightly smaller than normal and may be distorted. It can spread to fruit and even twigs and branches. It first becomes noticeable when young leaves emerge in spring.

Leaves affected by Powdery Mildew

YELLOW / OLIVE AREAS ON LEAVES

Scab not only affects the leaves of apple trees it also affects the fruit so check the fruit section lower down this page to confirm that you have this fungal disease. As well as yellow and dark green spots on the underside and top of leaves you may also see groups of the spores growing as small brown velvety mounds on the underside of leaves. Go to our dedicated apple scab page for treatment and prevention methods.

Leaf affected by Apple Scab

SMALL GREEN CATERPILLARS ON LEAVES, LEAVES AND BUDS DAMAGED

This pest is the Winter Moth and will normally become apparent in late March to May. The first indication will be tiny caterpillars on and around fruit and leaf buds. They may spin silken threads and hang from the tree twigs. They then grow into larger caterpillars and will eat leaves, buds and almost all parts of the foliage. Consult our Winter Moth page for more details.

Winter Moth Caterpillar hanging by a thread

PEST AND DISEASES AFFECTING APPLE TREE BRANCHES AND TRUNK

BARK CRACKED, PATCHES OF BARK SUNKEN DOWN

Canker is a fungal infection which enters tree wood at the site of existing damage, normally caused by bad pruning techniques although damage by woolly aphid (see above) can also allow the fungus to enter the tree. It can affect individual branches, stems and even more seriously the main tree trunk.

BRANCHES HAVE IRREGULAR LUMPS ON THEM

See the picture below for the signs of galls, also known as burls. These lumps are due to genetic changes in the tree caused by bacteria entering the wood, often at the site of a wound. In some cases they can be so bad that the tree is killed but in many cases there are no noticeable side effects.

The only permanent solution is to destroy the tree. The bacteria will remain in the soil for two three more years.

Apple tree stem affected by Galls

BRANCHES HAVE ELONGATED WHITE FLUFFY AREAS ON THEM

The visible white fluffy areas are restricted to stems and branches, occasionally the main trunk. The areas tend to be elongated rather than round. Where additional infections occur the fluffy material may become spotted black or grey. This is woolly aphid and although unlikely to kill an apple tree it will encourage other infections such as canker which can severely damage and kill an apple tree.

Apple tree stem affected by Woolly Aphid

PEST AND DISEASES AFFECTING APPLE TREE FRUIT

INSIDE OF THE APPLES HAS A BROWN TUNNEL IN IT

Unless you have experience of Codling Moth it’s likely the first sign of damage will only be apparent when you cut open the apple.

There will be a tunnel in the fruit of varying length which is brown in appearance and filled with excrement from the caterpillar. This damage has been caused by the caterpillar stage of the for our detailed page on identifying and treating this pest.

Apple affected by Codling Moth

SKIN HAS BROWN, PIN HEAD SIZED MARKS. FRUIT TASTES BITTER

In addition the flesh may have similar marks in it. If you cut the apple in half the marks on the skin will also be in the flesh, sometimes right to the middle. This is without doubt caused by for more identification and treatment details.

Apple affected by Bitter Pit

SKIN HAS BROWN RASED OR SUNKEN AREAS

The fruits have greyish, slightly raised or sunken areas on the surface. This is most likely caused by apple scab. The affected area will not grow with rest of the apple, causing it to split eventually, providing an ideal site for other infections to enter. See also problems affecting leaves above because scab affects the leaves as well.

Apple affected by Scab

BLOSSOM WILT

Blossom Wilt affects fruit trees including apples, pears, plums and cherries. It is a fungal disease (Monilinia laxa and Monilinia fructigena) which has the following symptoms:

  • Blossoms wilt then shrivel up and become dried out.
  • Leaves near the blossoms (on the fruiting spurs) also turn brown and shrivel up.
  • If conditions are damp, the affected leaves will have small, light brown, fungal raised areas on them.
  • If any fruit manages to survive it will turn brown and rot.

Damage by Blossom Wilt

There are no chemical controls available to UK gardeners to control this fungal infection.

Non-chemical control is based on pruning off any damaged blossoms including the fruiting spur they are on. Burn them, do not put them on the compost heap. Do the same with any fallen leaves. The idea is to minimise the spread of the spores and hopefully prevent them over-wintering and re-infecting the tree the next year.

EUROPEAN RED MITE

Lots of small, red eggs on the bark of the tree branches. Commonly, but not always, these are found in the join between one branch and another. The picture below (courtesy of David H) can be used to identify them.

The red eggs are from the European Red Mite. Because I have never encountered them personally I can’t really offer advice as to how to control them. However I do know that they are eggs which will hatch out in spring and become tiny red mites.

These will damage the leaves of your apple tree. I would certainly scrape the eggs off immediately before they hatch and take a close look around the tree for more of them. When the eggs hatch they loose their colour so this will give you an idea of the scale of the problem this year.

To the best of my knowledge the European Red Mite is not connected with the more common Red Spider Mite. More information can be found on the link here.

If you’ve noticed little white flurries flying through the air and covering leaves, it’s not an early snowfall. Asian woolly hackberry aphids are currently coating trees in the Upper South, and plaguing homeowners by creating a sticky and moldy mess.

Just like stink bugs, these pests usually appear in fall, with sightings reported in the Southeast, southern Midwest, Texas and California, according to HGTV. While the bugs don’t bite or sting, they still cause a nuisance by producing a sweet, sticky honeydew as they feed on the sap of sugarberry and hackberry trees. The clear goop then falls on sidewalks, cars and anything below them.

The honeydew causes further annoyance by then promoting the growth of “sooty mold,” a type of fungi that looks like, well, sooty mold. While the dark grit may cause trees to drop their leaves earlier, scientists haven’t discovered any negative long-term effects. That doesn’t mean homeowners don’t want to get rid of the fluffy bugs though.

The aphid’s copious amount of waxy wool defends against predators. Nature’s ImagesGetty Images

To remove the fluffy aphids from your property, you can start by spraying them with water. A little bit of pressure from the hose can blast away aphids without stripping off foliage, advises horticulturist Amy Dismukes of the University of Tennessee. Prevent them from spreading further by giving shrubs plenty of TLC as well.

“As always, healthy plants are less prone to attack, so utilize some cultural controls to make your hackberry happy,” she wrote in her Spring Hill Home Page column. That includes appropriate soil moisture, undisturbed roots and no fertilizers unless there’s a nutrient deficiency.

Non-residual, contact insecticides may also reduce the woolly aphid population. Bonide Horticultural Oil or Safer Brand Insect Killing Soap can keep things in check, according to the University of California’s Statewide Pest Management Program.

If the aphids plague your yard every year, consider applying a systemic insecticide like Bayer Advanced 12 Month Tree & Shrub Insect Control or Bonide Annual Tree & Shrub Insect Control Concentrate around trees’ trunks in late winter or early spring. Never apply these products while plants bloom, as they can harm the aphids’ natural enemies and important pollinators. Don’t bother in the fall either, since the leaves will soon drop anyway.

While these pests may irritate you now, have hope knowing they won’t stick around much longer. The first frost usually wipes mature aphids right out as their eggs overwinter, creating a mess all over again next year.

How to Get Rid of Fruit Flies

[h/t WRCB TV

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How to Identify and Get Rid of Wooly Aphids

How to Get Rid of Wooly Aphids

Courtesy of Wikimedia Commons

Now that summer’s over and fall has begun, t’s that time of year in Tennessee when you start to see what appear to be little fuzz balls floating around. They just look like they might be lint or some other type of fabric from your clothing or furniture floating around. If you look closely, though, those fuzzy things are really an insect called the wooly aphid.

Wooly aphids appear to be fuzzy because they are covered in a waxy substance. The bugs themselves are blue or green.

Wooly aphids are harmless to humans, and they rarely cause much of a problem. However, it is possible that they could cause a significant amount of damage to your yard and plants. You may have to then get rid of wooly aphids.

Wooly aphids live in groups, and these groups can get rather large. As they feed on the plant life around your yard, you may notice some leaves and grass become shriveled and curly. Here are some other signs that you may need to get rid of wooly aphids:

Courtesy of Wikipedia.

  • Yellowing of leaves
  • Poor plant growth
  • Curling and gnarling of branches
  • Cankers on branches and roots
  • Sticky residue
  • Soot-like substance on plants

If these are becoming a problem, there are a few natural ways you can get rid of wooly aphids. These include insecticidal soap, neem oil, or even removing infected branches. These methods may get rid of wooly aphids on their own, but this is not necessarily the case. You may have to get professional help to get rid of wooly aphids.

If you’ve tried the methods above and still can’t get rid of wooly aphids, it may be time to call Absolute Pest Control. Call us at (615)220-1933 or click here to schedule an appointment.

Woolly Aphid Stock Photos and Images

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  • Woolly aphid on apple branches.
  • Woolly Aphid – Eriosoma lantigerum
  • Woolly aphid Eriosoma lanigerum colony and waxy extrusions on apple wood
  • Woolly Aphid – Eriostoma lanigerum
  • Woolly aphid (Eriosoma langerum) colony on apple branch
  • Woolly aphids on tree branch.
  • Woolly Aphid – Eriosoma lantigerum
  • Gall on apple wood caused by woolly aphid Eriosoma lanigerum feeding
  • woolly aphid, gall aphid (Eriosoma ulmi, Schizoneura ulmi), damage of leaves, Germany
  • Woolly aphid Eriosoma lanigerum colony and scars with waxy extrusions and aphids on apple wood
  • A beautiful Woolly Aphid(Eriosoma lanigerum) with purple wings, long antennae and white fluffy tail; clings to the end of a twig facing the sunlight.
  • WOOLLY APHIDS ON BRANCH OF AN APPLE TREE (MALUS). are sucking insects that live on plant fluids and produce a filamentous waxy white covering.
  • Red larch gall adelgid, Larch adelges, Larch woolly aphid, Ananasgalle, Ananas-Galle, Fichtengalllaus, Galllaus, Adelges spec.
  • Damage caused by the Woolly aphids,Clingman’s Dome,Great Smoky Mountain National Park
  • Woolly aphids on leaf
  • Woolly aphid, Eriosama lanigerum
  • The sticky cotton wool like sign of Woolly Aphid infestation on an apple tree.
  • Woolly aphid , scale insect, Eriosoma spp on underside of Viburnum tinus leaves, start of infestation
  • Woolly aphid or American blight – Eriosoma lanigerum on Cran Apple Malus ‘Red Sentinel’
  • Balsam woolly adelgid disease,Clingman’s Dome,Great Smoky Mountain National Park
  • Mealy bug,Pseudococcus spp. on a succulent stem.
  • Greenfly
  • Woolly aphids (subfamily: Eriosomatinae) on a Heartleaf iceplant (Aptenia cordifolia) succulent plant. Woolly aphids (subfamily: Eriosomatinae) are su
  • Woolly aphid (Eriosoma langerum) colony on apple branch
  • Woolly aphids on tree branch.
  • Woolly aphid Eriosoma lanigerum attacking young apple branch cu
  • Woolly apple aphid
  • woolly aphid, gall aphid (Eriosoma ulmi, Schizoneura ulmi), six woolly aphids on a withered leaf, Germany
  • Woolly aphid Eriosoma lanigerum colony and scars with waxy extrusions and aphids on apple wood
  • red larch gall adelgid, larch adelges, larch woolly aphid (Adelges spec), red larch gall at a pine twig, Germany
  • A beautiful Woolly Aphid(Eriosoma lanigerum) with purple wings, long antennae and a white fluffy tail; clings to the end of a twig – wings spread.
  • Red larch gall adelgid, Larch adelges, Larch woolly aphid, Ananasgalle, Ananas-Galle, Fichtengalllaus, Galllaus, Adelges spec.
  • Parasitised and healthy woolly aphids on apple tree. Aphids turn to black mummies when parasitised by Aphelinus wasps.
  • Woolly aphid infestation on a garden Pyracantha shrub.
  • Woolly aphid, Eriosama lanigerum
  • WOOLLY APHIDS (ERIOSOMA LANIGERUM)
  • Woolly aphid , scale insect, Eriosoma spp on underside of Viburnum tinus leaves, start of infestation
  • Woolly aphids (subfamily: Eriosomatinae) on a Heartleaf iceplant (Aptenia cordifolia) succulent plant. Woolly aphids (subfamily: Eriosomatinae) are su
  • Woolly Maple Aphids, Neoprociphilus aceris, on bristly greenbrier, Smilax tamnoides
  • Mealy bug,Pseudococcus spp. on a succulent stem.
  • Aphids on the grass
  • Woolly aphids (subfamily: Eriosomatinae) on a Heartleaf iceplant (Aptenia cordifolia) succulent plant. Woolly aphids (subfamily: Eriosomatinae) are su
  • Woolly Maple Aphid, Neoprociphilus aceris, colony on bristly greenbrier, Smilax tamnoides
  • Close-up of Wooly Alder Aphid bug on tree branch
  • Harvester, Feniseca tarquinius, larva among Woolly Maple Aphid, Neoprociphilus aceris, colony on bristly greenbrier, Smilax tamnoides
  • Mealybug on leaf figs. Plant aphid insect infestation Ficus elastica
  • Ananasgalle, Ananas-Galle an Fichtentrieb, Fichte, Fichtengalllaus, Fichtengallaus, Fichtengall-Laus, Fichtenkleingallenlaus, Fichtengallenlaus, Ficht
  • Woolly aphid Eriosoma lanigerum colony and scars with waxy extrusions and aphids on apple wood
  • red larch gall adelgid, larch adelges, larch woolly aphid (Adelges spec), red larch gall at a pine twig, Germany
  • NORTH CAROLINA Mount Mitchell State Park Fraser Fir and Red Spruce evergreen trees killed by acid rain and balsam woolly aphids
  • Woolly beech aphid (Phyllaphis fagi), damage of beech leaves, Germany
  • Woolly aphid or mealy bug infestation attacks palm tree in Tenerife where high rainfall levels have caused rot and disease
  • woolly larch aphid Potton Bedfordshire
  • Woolly aphid, Eriosama lanigerum
  • Aphids – Shrubs- – Woolly aphid on Pyracantha- – (Eriosoma lanigerum) PES111330 Photos Horticu
  • Woolly aphid , scale insect, Eriosoma spp on underside of Viburnum tinus leaves, start of infestation
  • Woolly aphids (subfamily: Eriosomatinae) on a Heartleaf iceplant (Aptenia cordifolia) succulent plant. Woolly aphids (subfamily: Eriosomatinae) are su
  • WOOLLY APHID in flight Sort of greenfly
  • Woolly Beach Aphid
  • Beech leaves infested with Woolly beech aphid (Phyllaphis fagi), close-up
  • Woolly Aphid Larva is species of plant lice of the Eriostoma family vintage line drawing or engraving illustration.
  • Hemlock Woolly Adelgid Infestation (Adelges tsugae)
  • Pine branch with raindrops
  • Harvester, Feniseca tarquinius, larva among Woolly Maple Aphid, Neoprociphilus aceris, colony on bristly greenbrier, Smilax tamnoides
  • Oleander leaves densely covered with scale insects. Mealy mealybug.
  • Harvester, Feniseca tarquinius, larva feeding on Woolly Maple Aphids, Neoprociphilus aceris, on bristly greenbrier, Smilax tamnoides
  • Woolly aphid Eriosoma lanigerum colony and waxy extrusions on apple wood
  • Harvester, Feniseca tarquinius, female ovipositing in Woolly Maple Aphid, Neoprociphilus aceris, colony on bristly greenbrier, Smilax tamnoides
  • Woolly aphid Eriosoma lanigerum infestation on an apple branch France
  • Woolly beech aphid (Phyllaphis fagi), on a beech leaf, Germany
  • Woolly aphid Eriosoma lanigerum colony on apple wood
  • red larch gall adelgid, larch adelges, larch woolly aphid (Adelges laricis)
  • Woolly aphid, Eriosama lanigerum
  • Ananasgalle, Ananas-Galle an Fichtentrieb, Fichte, Fichtengalllaus, Fichtengallaus, Fichtengall-Laus, Fichtenkleingallenlaus, Fichtengallenlaus, Ficht
  • Woolly aphid , scale insect, Eriosoma spp on underside of Viburnum tinus leaves, start of infestation
  • Mealybug on hibiscus flower. Plant aphid insect infestation. Thick
  • Boxwood with white waxy coating or extrusion from box sucker or boxwood psyllid, Psylla buxi
  • Woolly aphid or mealy bug infestation attacks palm tree in Tenerife where high rainfall levels have caused rot and disease
  • WOOLLY APHID in flight Eriosoma lanigerum Sussex, England
  • Adult Woolly Aphid a species of plant lice of the Eriostoma family vintage line drawing or engraving illustration.
  • NORTH CAROLINA Mount Mitchell Red spruce and fraser fir trees killed by balsam woolly aphids after being weakened by acid rain
  • Hemlock Woolly Adelgid Infestation (Adelges tsugae)
  • Fir branches in the park
  • The first pine needles of spring shed their husk as they mature in soft sunlight
  • Coniferous forest road
  • Blue Ridge Virginia US. Damage on the Fraser fir and hemlock done by the Balsam Woolly Adelgid, an introduced aphid pest.
  • Harvester, Feniseca tarquinius, female ovipositing in Woolly Maple Aphid, Neoprociphilus aceris, colony on bristly greenbrier, Smilax tamnoides
  • Dead Hemlock, Hemlock Springs, Shenandoah National Park, Virginia, USA
  • Woolly beech aphid, Phyllaphis fagi, on the underside of young beech hedge leaves
  • Woolly aphid Eriosoma lanigerum infestation on damaged apple shoot
  • red larch gall adelgid, larch adelges, larch woolly aphid (Adelges laricis)
  • Woolly Aphid (Eriosoma lanigerum) colony on apple pruning scar
  • Woolly aphid, Eriosama lanigerum
  • Woolly aphid Eriosoma lanigerum waxy extrusions and aphids on apple wood
  • red larch gall adelgid (Adelges spec., ), pineapple gall at spruce, Germany
  • Boxwood with white waxy coating or extrusion from box sucker or boxwood psyllid, Psylla buxi
  • Ananasgalle, Ananas-Galle an Fichtentrieb, Fichte, Fichtengalllaus, Fichtengallaus, Fichtengall-Laus, Fichtenkleingallenlaus, Fichtengallenlaus, Ficht
  • Mealybug on hibiscus flower. Plant aphid insect infestation. Thick
  • Woolly aphid or mealy bug infestation attacks palm tree in Tenerife where high rainfall levels have caused rot and disease
  • WOOLLY APHID taking off Eriosoma lanigerum Sussex, England Note the independent movement of the two pairs of wings

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Today as I was driving across Vermont I saw a lot of milkweed seeds floating in the breeze. These were the first I had noticed this year, maybe more because I haven’t been spending much time in open fields than because this was the first day they’ve been dispersing. For the past couple of weeks, though, I’ve been seeing some much smaller bits of white fluff drifting by me on my walks in the woods. These are woolly aphids (Eriosomatinae), whose bodies are covered with white, waxy filaments.

The reason aphids are on the move in the fall is that they are migrating to new host plants. Many aphid species use one kind of plant for part of the year and another kind of plant for the rest. For instance, the two species that make galls on witch hazel (one of which I showed in my last post) both live on birch leaves for part of their life cycle. The general story for aphids with alternating hosts is something like this: In the fall, eggs are laid on bark of the primary host, where they overwinter. These are an important food source for chickadees and other bark-gleaning birds. The aphids that hatch from eggs in the spring are called fundatrices; they are all female and are parthenogenetic (they don’t mate) and viviparous (give birth to live young rather than laying eggs). Their offspring are likewise all female, parthenogenetic, and viviparous, but are called fundatrigeniae or virginoparae, as are the members of the subsequent generations through the summer. (I could explain this without all the terminology, but any time you read about aphids you will encounter these terms, so I’m including them here in the hope that it will help us all keep them straight.) Sometime in the spring, alatae (winged adults, as opposed to apterae, the wingless ones) take off in search of the secondary host, which is often an herbaceous plant. Parthenogenetic reproduction continues on the secondary host until the fall, when winged adults called sexuparae arise and return to the primary host. Here, they give birth to sexuales, a generation of males and females, which reproduce sexually. After mating, the female sexuales lay eggs, completing the cycle.

So the little bits of fluff floating through the woods are woolly aphid sexuparae. It’s possible that they belong to a species of Eriosoma, in which case they are looking for elm trees, leaving behind (depending on which species of Eriosoma) a shadbush, hawthorn, or apple, their descendants destined to distort elm leaves in the spring. But there are 22 other genera of woolly aphids (as in Eriosomatinae; a number of other aphid subfamilies also have species that are woolly) in North America, and for all I know some of them look just like Eriosoma.

Incidentally, in reviewing my woolly aphid photos for this post, I came across some I took this spring of one on the underside of a hackberry leaf. When I took the photos, I didn’t think that hackberry was necessarily the host plant, but I now see that the aphid was in the process of depositing nymphs. As far as I can tell, the only woolly aphid in the world known to feed on hackberry is Shivaphis celti, the Asian woolly hackberry aphid, which this clearly is not (it lacks the banded antennae and patterned wings, among other things). I wonder if this is an elm-feeding species that messed up (hackberry being in the same family as elm), or something new to science… if I come across these again, I’ll have to investigate further.

Look closely and you’ll see a nymph lying on its back under this woolly aphid on a hackberry leaf.

This shot shows a nymph in the lower right corner. The nymph from the previous shot is still under her mother but is more obscured.

My go-to reference for aphid information is this website, where Roger Blackman and Victor Eastop are generously providing the content from their extremely expensive books.

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