How to fight red thread lawn disease: Ask an expert

By OSU Extension Service and Master Gardeners

Winter is bearing down fast, but there’s still plenty to do in the garden. What’s up in yours? Got a question? Get answers from Ask an Expert, an online question-and-answer tool from Oregon State University’s Extension Service. OSU Extension faculty and Master Gardeners reply to queries within two business days, usually less. To ask a question, simply go to the OSU Extension website and type in a question and the county where you live. Here are some questions asked by other gardeners. What’s yours?

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Courtesy of OSU Extension Service

What’s this pink visitor in the lawn?

Q: The images included, taken Nov. 28, are from the grass area in the back yard. The grass area is the highest ground in the garden and our lot might be the highest in the block. The grass area in question was “solarized” (sod lifted, raked, dug, sifted, amended) and sown with dwarf rye grass two or three years back. The effort was to remove the clover that brought honey bees too close to the play area, (allergic to bees). The clover is under control, but the second season after sowing I noticed the brown patches in the new grass. At first I thought it might be urine, crane fly or some grub. Spring growth the next season sort of filled in the dead grass areas and concerns were put at rest. I did lift some sod but found no obvious intruders. Currently, there are more (new) brown spots in the grass and the older brown spots now support this pink gelatinous curiosity. Any insight as to this pink visitor would be appreciated.

– Multnomah County

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Courtesy of OSU Extension Service

A: This sounds like red thread lawn disease caused by the fungus Laetisaria fuciformis. This article, Lawn and Turf Red Thread, gives more information. The signs are red threads from the tips of the grass blades and pink gelatinous globs. It appears in fall, winter and early spring. When the weather warms up and the grass is growing well, you won’t see it. To confirm you can either send or take a sample of your lawn grass near the pink globs to your local Master Gardener office. They can look at the grass through a microscope.

To control red thread, fertilize your lawn with high nitrogen, but balanced fertilizer. Red thread occurs more frequently in undernourished turf. When you mow, use a grass catcher and dispose of the grass tips with the fungus. Disinfecting the soles of your shoes and the underside of your mower with bleach diluted 1 part to 10 parts water can also help. The Common Sense Gardening Guide to Lawn Care has good information on growing lawns and a discussion of red thread on page 12.

– Anne Schmidt, OSU Extension Master Gardener

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Courtesy of OSU Extension Service

What’s that fuzzy stuff on this jade plant?

Q: I just noticed this white fuzzy stuff on my jade plant on the stem near the leaves. What is it? How do I get rid of it and stop it from spreading and happening again? Will it spread to the plants I have around it? I am only watering it once a month and just watered it on the first of the month. It does have drainage in the bottom of the pot.

– Multnomah County

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A: The image clearly displays mealybugs, common insect pests of indoor plants.

Yes, they can spread to your other indoor plants. (A hint to avoid problems indoors: Whenever you obtain a new plant, isolate it for at least a month even as you check periodically for unrecognized hitchhiking insects and or diseases.)

Mealybugs move very slowly. They normally develop a white, waxy coating, which tends to repel certain pesticides. Even so, you can easily kill them with direct hits of alcohol, applied as a fine spray; repeat as needed.

Please be aware that jade plants are succulent plants. As such they are extremely sensitive to certain pesticides. Before you obtain any other product as a remedy for them, ask the retailer if the product is safe to use on succulent plants grown indoors.

– Jean Natter, OSU Extension Master Gardener

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Doug fir mystery

Q: We have noticed that a very tall older Doug fir some 100 feet behind our house is full of tiny green glowing orbs at night. Insects of some kind? These are very bright and can be easily seen after dark with the naked eye. We looked at them with binoculars last night and we could see many more – hundreds! They appear to be on the needles as well as the trunk of the tree. We have also spotted a few on the huge Doug fir behind our house also, but so far none on the huge Doug fir in front of our house. Do you know what these are and if they cause damage to the tree? They are quite an interesting phenomenon that I have never seen before.

– Multnomah County

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A: Douglas fir glowworm (Pterotus obscuripennis) is most likely, as it is the right time of year to see them. You’ll find information online about them and they are not anything to try to remove from the trees.

Bugguide has photos of both the adult and larvae.

– Jacki Dougan, OSU Extension Master Gardener

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Watering airplants

Q: I think my airplants are overwatered. What to do?

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A: I referred to the book “Tillandsias II,” by Paul T. Isley III, for detailed information on these fascinating plants.

Let me give you the signs of over-watering, first. Starting with the innermost leaves, tug one gently. If the leaf comes off and the base is dark, there’s a problem. But, this might not be the end. Continue to remove these darkened leaves. Isley says that if even a few healthy leaves remain, the plant may still recover.

Tillandsias should not be planted in soil or left in water. They should be submerged in water once or twice a week for up to 12 hours, but not for more than a day or they can “drown.” Shake the plant off and place it back in its container or holder. In the low humidity of the winter home, misting the plant occasionally wouldn’t hurt, but that is not a substitute for a dip.

Under-watering is more common. Watch for the leaves to curl inward. Increase the frequency of watering, if this happens, but not the amount of time the plant is in the water.

Several sources warn of hard water that is “softened.” In general, tap water should be fine.

I am includingout of Illinois. They have a somewhat different environment than Clackamas County, but the care guidelines match up with Isley’s.

– Claudia Groth, OSU Extension Master Gardener

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More advice from the experts

  • How to control gnats in houseplants
  • To top or not to top trees?
  • How do you treat a stem canker in a maple tree?
  • How to control creeping bamboo and salal
  • How to prune hydrangea and eradicate tree of heaven
  • What’s the best grass seed for Portland lawns?
  • What causes yellow leaves on Oregon myrtle

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Red Thread

Look out it’s the red menace…

Red Thread is the most common lawn fungal disease in the UK and at some point it is highly likely that your lawn will suffer from it at some degree, even though it might not be enough for you to notice. Red Thread tends to be a bit of a nuisance rather than a fatal lawn disease as it does not kill the roots of the grass plant. With good practice it should be fairly easy to control without the need to rely on the use of fungicides every time there is an outbreak.

Lawns can look very unsightly for several weeks during an outbreak of Red Thread. This disease can be identified during the early stages by a tiny pink fungus which forms on the leaf of the plant which then causes the leaf to turn a bleached colour through the latter stages. Small or large areas of lawn can be affected and it can happen at any time of the year – at times weather patterns might trigger an outbreak.

Some lawns and grass types tend to be more susceptible than others and there are a variety of reasons for this. Lawns grown on inert or soils with low nutrient capacity are often the worst affected and some modern varieties of grass species have less resistance.

The way we manage our lawns can make a difference on how the grass plants resist the red thread fungus. Modern fungicides will stop the fungus from spreading and will protect against attack for a limited period of time but are not a long term solution. It is far better to work with prevention over a long period of time rather than a short term cure.

Pinkish-red strands in grass could be red thread

The frequent rains this year have not only resulted in mowing challenges, but have also resulted in some turf areas in need of nutrition. Not surprisingly, Michigan State University Extension has received reports of red thread (Laetisaria fuciformison) on lawns and landscape turf areas for several weeks now.

It seems that every year we observe red thread on lawns or golf course roughs and often the outbreak follows the seedhead production period when the plant is probably looking for a little extra nutrition. The common lawn mix turfgrasses Kentucky bluegrass, perennial ryegrass and fine fescue are all susceptible, with perennial ryegrass being particularly susceptible.

Red thread is typically active during wet, moist periods when temperatures range from 55 to about 80 degrees Fahrenheit. Red thread can be identified by the pinkish-red strands (stroma) that extend from the leaf blade tip. The pinkish-red strands are easily observed in the morning when the turf is still moist from dew. The areas infected by red thread will die and the turf may appear wilted. Red thread can be mistaken for dollar spot in turf as the patchy type kill is very similar. This is one of those diseases you need to get on your hands and knees to check out to make sure you know that it is red thread.

Close up of red thread in turf. Photo by Kevin Frank, MSU

Fungicide applications are usually not necessary in dealing with red thread; a fertilizer application will often help the turf outgrow the damage.

Dr. Frank’s work is funded in part by MSU’s AgBioResearch.

Lawn Disease Control
Controls fungal diseases on established lawns.
Protects the lawn against common lawn diseases such as fusarium patch and red thread.
Prevents and cures diseases. Maximum number of treatments per year = 2. Allow 4 weeks between treatments.
Allow product to dry before using the lawn.
Use at first sign of disease.
Can be used at any time of year.
Soluble sachet formulation.
Just drop into the sprayer or watering can.
Children and pets need not be excluded from treated areas once dry.
Most common lawn diseases such as fusarium patch and red thread.
Application method:
Advice on application:
For the control of Red Thread and moderate control of Fusarium Patch. Can be used all year round. Spray at the first indications of infestation and where disease has been identified treat the whole lawn.
Red Thread
• First appears as circular pink/bleached patches in the grass.
• Disease can rapidly expand into large patches, with dead grass. Red, threadlike strands form near the tips of the leaf blades.
• To identify Red Thread, keep looking for the pink colour.
• Red Thread is more prevalent when warm during late spring, summer and early autumn.
Fusarium Patch
• First appears as dull brown small spots on the lawn that can spread rapidly and can become large dead patches.
• This disease is more prevalent in the autumn from October onwards and in the spring.
How to use:
Calculate the size of the area to be treated and mark into 20sqm sections. Apply the product with a sprayer.
1. Tear open the sachet and drop the inner water-soluble bag into a sprayer containing 1 litre of water.(Do not open inner water-soluble bag!)
2. Allow to stand for 2 minutes until the inner water-soluble bag dissolves then shake gently to mix.
3. Spray evenly over 20sqm of lawn.
Precaution for use:
• Do not touch water soluble bag – place whole bag directly into spray tank.
• Do not apply during drought conditions or to frozen turf. Can be applied after mowing and if applied before mowing, do not mow for at least 48 hours after application to allow adequate movement of the treatment through the plant. Allow the spray to dry before using the lawn.
• Only apply to established garden lawns and residential turf. The maximum number of treatments is two per year with a minimum of four weeks between treatments.
• For further information, refer to product information.

Bleached grass blades with fuzzy, pink to red masses of spider web-like strands are typical of red thread(R. Latin, Purdue Univ)

Benjamin Van Ryzin, UW-Madison Plant Pathology
Revised: 6/23/2013
Item number: XHT1233

What is red thread? Red thread is a foliar disease of cool-season turfgrasses. Grass species affected by this disease include fine fescues (the species most commonly affected), tall fescue, perennial ryegrass and Kentucky bluegrass. These grasses are commonly used for home lawns, golf course roughs, parks and athletic fields in the Midwest. Although red thread is not lethal, it can cause unsightly bleaching of large areas of a lawn.

What does red thread look like? Red thread is often misdiagnosed as pink patch, another turf disease that develops under similar environmental conditions. Both diseases cause tan, pink, or red circular patches ranging in size from a few inches to two feet in diameter. In addition, both diseases are noted for the formation of pink to red, spiderweb-like threads along the edges of diseased areas when leaves are wet. Leaf blades affected by both diseases die starting at the tip, becoming a tan, light-gray or bleached-white color. Red thread can be distinguished from pink patch by the presence of thick, red tendrils that protrude from affected leaf blades. These tendrils are the “red threads” that give the disease its name.

Where does red thread come from? The fungus, Laetisaria fuciformis, causes red thread. The fungus grows from the red, thread-like structures (called sclerotia) that survive the winter in infected grass blades, thatch and soil. Sclerotia and infested leaf blades can be moved by water, wind and mowing equipment to other locations where they can cause new infections. Red thread most often develops in wet, cool (59 to 77°F) weather in the spring and fall. The disease is most severe on fine fescues (although other turfgrass species also can be affected) that are growing slowly due to cool weather or inadequate fertilization.

How do I save turf with red thread? Red thread is a cosmetic disease that does not affect either the crown or roots of infected plants. Thus, turf with red thread typically recovers after environmental conditions favorable for growth return and conditions favorable for disease development have passed.

How do I avoid problems with red thread in the future? When seeding or sodding a lawn, choose grasses, that are less susceptible to red thread (e.g., Kentucky bluegrass and hard fescue). If you use susceptible grass species (e.g., fine fescues and perennial ryegrass), be sure fertilize your lawn optimally in the fall and spring to maintain its growth and vigor. See University of Wisconsin-Extension Bulletin A3435 “Lawn Maintenance” (available at for recommendations on routine lawn fertilization. On lawns with a history of red thread, apply nitrogen fertilizer in mid to late spring to reduce disease severity and promote healthy turf. Under dry conditions, water your lawn between midnight to 6 am when dew naturally forms, thus reducing the length of time that your lawn remains wet. Red thread often develops when turfgrass is watered frequently, so DO NOT water your lawn unless you observe wilting.

Fungicide use is not generally recommended for control of red thread due to the cosmetic nature of the disease, the fact that infected turfgrass typically quickly recovers from the disease and the cost of chemical control. However, if you feel that fungicide treatments are needed, products containing strobilurins (e.g., azoxystorbin, trifloxystrobin and fluoxastrobin), as well as flutolanil are currently labeled in Wisconsin for managing red thread and can be very effective when applied before symptoms appear. When using fungicides, DO NOT apply the same active ingredient for all treatments. Instead, alternate the use of at least two ingredients with different modes of action (i.e., DO NOT only use strobilurins) to help minimize problems with fungicide-resistant strains of the red thread fungus. Be sure to read and follow all label instructions of the fungicides that you select to ensure that you use the fungicides in the safest and most effective manner possible.


Additional Images

Red thread-like structures, called sclerotia, protrude from leaf blades infected by the red thread fungus.(PC: Paul Koch)
Tags: disease Categories: Lawn Problems, Lawns

How do I get rid of Red Thread disease?

Almost any lawn is susceptible to this turf fungus. However, it isn’t uncommon for some lawns to have more issues than neighboring properties. Property owners often wonder what can be done to get rid of Red Thread on lawns when it shows up each year. The remedy is to disrupt the disease triangle so that this fungus stops growing. The disease triangle is used to illustrate how fungi grows on plants, in this particular case, your lawn. The susceptible host are grass plants that are lacking in nitrogen and have started to not grow as aggressively as they have in the months prior. The pathogen is present in the thatch layer of a lawn and impossible to completely remove. When the plant is weak, and the temperature and relative humidity is favorable, Red Thread will begin and continue to grow.

Since it’s not possible to remove the pathogen nor control the weather, the most effective way to get rid of Red Thread is to address the susceptible host plant. Fertilizing lawns in late spring and early summer will help to provide nitrogen. As that nitrogen gets watered in, most lawns will grow-out this specific turf disease problem. That being said, there are instances where Red Thread can become a chronic problem or advance past normal levels and a fungicide treatment may be required. This isn’t typical, but it can happen.
Having a properly executed lawn care program and a lawn care company that employs true lawn care experts can help with your Red Thread issues. Lawn care programs that deliver a steady amount of nitrogen throughout the year, particularly in the times of probably infection, will help your grass to push out this specific disease. Your lawn expert can also let you know if your situation would warrant the extra help of a lawn disease control treatment for Red Thread. Some turf diseases are aggravated by excessive fertilization so be sure to have an expert diagnose which disease your lawn is facing before fertilizing your lawn. If you need help diagnosing or treating a turf disease or other lawn care problem, please don’t hesitate to contact us.

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