From the Pests of Ornamental Series
- John F. Baniecki, Ph.D.
- WVU Extension Service
- Plant Pathology and Entomology Specialist
8/2000
A beautiful lawn takes time, patience, proper care, and a never-ending watchful eye.
The following lawn care tips can reduce many lawn problems:
- Do not over fertilize to promote fast lush growth, especially in hot, humid weather.
- Collect clippings to avoid thatch (layer of living and dead stems, leaves, and roots of
grasses which develops between the layer of green vegetation and the soil surface) where
certain disease causing organisms and insects thrive.
- Maintain adequate soil moisture with infrequent but deep watering. Light, daily
water-rings favor many disease causing organisms.
- Maintain the proper soil pH. If in doubt, obtain a soil analysis.
- Keep the lawn clipped at the proper height. Too short a cut will weaken the grass and
make it susceptible to a disease, and too tall a cut will hold moisture so the grass fails
to dry rapidly.
- Mow frequently so that not more than 1/4 to 1/3 of the total leaf surface us removed
each time.
- Remove thatch when it accumulates to 3/4" or greater.
- Mow the lawn throughout the fall until the, grass stops growing.
Carefully inspect your lawn, periodically throughout the growing season. Be on guard,
when a lawn problem arises. Many problems, if corrected early, can be remedied. During the
growing season keep a watchful eye for:
- 1. Brown or dead spots
- The season of the year in which they appear and previous lawn practices may be clues to
the problem.
- 2. Fertilizer burn
- When was fertilizer last applied? How much? Look for brown spots or streaks where heavy
applications may have been made (around trees, shrubs, etc.). A uniform brown cast may be
fertilizer burn. Fertilizer may burn if applied when the grass is wet and the fertilizer
is not washed off immediately.
- 3. Disease
- Certain species of grass are more susceptible to given diseases than others. Bentgrass
often gets Dollar Spot in May, June, September, and October. Common Kentucky bluegrass is
susceptible to Drechslera Leaf Spot and may be seriously affected; the entire lawn
appearing brown after mowing. Some areas may be more seriously affected than others. A
black Slime Mold may develop on grass during wet weather.
- 4. Insect Damage
- Grubs may kill large areas of a lawn. Worst damage shows up in late summer. In
affected.areas, the sod can be rolled back like a carpet to reveal the grubs. Extensive
bird and skunk feeding are signs of grubs, Sod Webworms live in the sod and feed on the
leaves and stems at night. The worms chew grass blades off just above the thatch line,
pull the blades into their silken tunnels and eat them. Injury appears as circular or
irregular brown patches of close-clipped grass. Where webworms are abundant, numerous
small holes (diameter of one's finger) are often found in the dead patches. These
holes are made by blackbirds seeking out the large sod webworms. Chinch Bugs may be a
problem when the weather is hot and dry. Large brown areas occur in sunny areas. Look for
the bugs in the circle of grass that has turned yellow around these dead patches.
- 5. Annual Bluegrass
- It is the nature of annual bluegrass to die during the summer. Dead annual bluegrass is
often mistakenly called "disease."
- 6. Dry Spots
- Punch the affected spots and adjacent green area with a knife blade or screwdriver. If
the brown spot is hard and the green area soft, a lack of moisture in the brown spot may
be the reason. Local dry spots occur because of poor condition, thatch, fungal growth in
soil, or other unknown causes. Bentgrass patches usually turn brown first in an otherwise
Kentucky bluegrass lawn.
- 7. Gasoline Spillage
- Petroleum products will kill grass.
- 8. Mowers in Poor Condition
- Dull mowers or mowers improperly adjusted may crimp the grass instead of cutting it. The
dead leaf tips will cause a general browning. Mowers in poor condition may cause grass to
fray. The grass will show a white cast and then brown on the tips.
- 9. Female Dogs
- Female dogs may cause green or brown spots on a lawn. The larger a dog, the drier the
soil, and the higher the temperature, the more damage will be done. In or around the
affected spot, the grass not killed will turn green because of nitrogen in the urine.
- 10. Improper Use of Pesticides or Other Chemicals
- Herbicides for controlling crabgrass, insecticides or fungicides can cause burn or brown
spots to occur.
|
