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National Seed News

Posted on: 6/3/19

What is anthracnose? This fungal disease affects many plants, including vegetables, fruits, and trees. It causes dark, sunken lesions on leaves, stems, flowers, and fruits. It also attacks developing shoots and expanding leaves. It can spread very quickly during rainy seasons.

Anthracnose is a general term for a variety of diseases that affect plants in similar ways. Anthracnose is especially known for the damage that it can cause to trees. Anthracnose is caused by a fungus, and among vegetables, it attacks cucurbits.

Anthracnose can survive on infected plant debris and is very easily spread. Like rust, it thrives under moist and warm conditions and is often spread by watering.


How to Identify Anthracnose

  • On leaves, anthracnose generally appears first as small, irregular yellow or brown spots. These spots darken as they age and may also expand, covering the leaves.
  • On vegetables, it can affect any part of the plant.
  • On fruits, it produces small, dark, sunken spots, which may spread. In moist weather, pinkish spore masses form in the center of these spots. Eventually, the fruits will rot.
  • On trees, it can kill the tips of young twigs. It also attacks the young leaves, which develop brown spots and patches. It can also cause defoliation of the tree.

Control and Prevention

How to Control Anthracnose

  • Remove and destroy any infected plants in your garden. For trees, prune out the dead wood and destroy the infected leaves.
  • You can spray your plants with a copper-based fungicide

Posted on: 5/08/19

Boxwoods have always been known to need some TLC when it comes to getting them through the normal northern Illinois winter. Like our needled evergreens, boxwoods and other broadleaf evergreens are very alive all winter. Boxwoods are usually sited with northern or eastern exposures or protected in some way from winter sunlight and winds. Plant breeders have increased their winter hardiness with some cultivars, but certainly not all of them. Protecting them with burlap from the sun or creating a temporary winter windbreak are the common ways to give them what they need. Some gardeners will treat the boxwood with an anti-desiccate before the temperatures fall below freezing and again on a mild day in late winter or very early spring. Anti-desiccates seal the leaves, preventing moisture loss.

The damage this spring has been extensive on old and new plantings alike. If this was a disease, damage would be scattered, and symptoms would have been present last summer. What is happening right now is environmental, primarily the severe cold we experienced over winter. Damage is uniform and to varying degrees based on where they are planted in the home landscape. Take a walk around the neighborhood and those differences are readily seen.

If the damage is minor, only the leaves at the edge of the canopies will have the brown, burnt look. Those leaves will fall away when 2019 growth begins. In many cases, the entire boxwood is browned, and recovery is questionable. If it is just the tips and browning is minor, plants typically will recover like in the past. More damage than that and the 2019 vegetative buds would be killed. Any regrowth will have to come from well within the canopy. Stems and twigs would be the next to go and then the desiccation moves further downward towards the crown. If you take a close look, those stems and twigs will be shriveled.

There is not a problem with replanting boxwood with boxwood. There is a disease known as Boxwood Blight that has been spreading in the United States and so far, has not been detected in Illinois. If possible, buy replacements that have been grown in Illinois. Ask the retailer if the boxwoods have been certified blight-free, if not Illinois grown. When planting, modify the backfill soil with organic matter to increase aeration and drainage. Water them well at planting time and monitor them regularly for water. It will take at least two years to establish, longer for larger boxwood. They will have a limited root system during this time, making them more susceptible to desiccation, especially in the winter.

Richard Hentschel is a Horticulture Extension Educator with University of Illinois Extension, serving DuPage, Kane and Kendall counties. Stay tuned to more garden and yard updates with This Week in the Garden videos at and the "Green Side Up" podcast at The 2019 Kendall County Master Gardener Help Desk is open from 9 a.m. to 12:30 p.m. Monday through Friday at 630-553-5823.

Posted on: 4/5/19

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Posted on: 7/19/18

Perhaps the most serious turf disease likely to occur in northern Illinois is summer patch and necrotic ring spot, two separate diseases that attack grass roots and previously were referred to as fusarium blight. Research continues to look for information on these diseases. Brown patch may also attack turfgrasses. These "patch diseases" are similar in appearance and management in lawns.

Summer patch and brown patch tends to be most active in hot weather, while necrotic ring spot tends to be most active in late spring and in fall. Disease symptoms often show under turf stress in summer, however. Crescent shaped or circular patches of dead grass, often with clumps of green grass inside, are a characteristic symptom (often called "frogeye"). Lawn and other turf areas with advanced disease development may show irregular dead areas and streaks. 

Patch diseases typically develop on turf with stress factors such as excessive thatch, poor soil conditions, sod installed over a poorly prepared site, irregular/excessive nitrogen fertility, and related problems. One typical situation in which these diseases occur is recently sodded lawns (within 2 - 5 years) put down over a clay soil, usually with good care (high watering & fertility) to keep the grass green and vigorous. This condition leads to poor root penetration and development, and also often a problem thatch layer.

Management of these diseases consists of correcting soil problems and implementing proper cultural practices, overseeding dead areas, and possibly fungicide applications. Improving conditions for root growth and reducing problem thatch is critical. Practices such as core aerifying and topdressing, along with sound fertilizing, mowing (avoid mowing too short), and watering are suggested. Spring and fall are suggested times for aerifying, assuming the turf is actively growing. Avoid heavy spring applications of nitrogen fertilizer. Focus most applications on the fall period. Fertilizers containing controlled-release nitrogen are suggested. Overseed dead areas with perennial ryegrass and resistant Kentucky bluegrass cultivars in late August or early September.

These management suggestions may not bring immediate results, but will get the patch disease under control in the long run. Fungicides are an option to help prevent further development on unaffected grass, but will not reverse the factors causing the disease or eliminate the disease. Fungicides treat the symptoms but not the cause of the problem.

Written by Bruce Spangenberg, former Extension Educator, Horticulture. University of Illinois Extension.