Tips for fighting lawn and garden pests

A variety of pest and disease problems can challenge the home gardener during the summer, said Ron Wolford, a University of Illinois Extension horticulture educator, who offers these tips for dealing with some of the common problems in gardens and lawns.

During July, be on the lookout for grubs hatching in the lawn.

"It takes about eight to 12 grubs per square foot to cause browning of grass," he said. "Browning occurs in August and September. Patches of brown grass that can be pulled up like a rug have most likely been damaged by root-eating grubs."

He suggests controlling grubs as they hatch with insecticides like Grub X or Merit, following all label directions and applying in early July. He added reducing lawn watering during the egg-laying time in June may reduce the number of grubs.

August through September is the best time to repair lawns. Seeding bare spots in the lawn during that time will allow the new growth to have enough time to germinate, grow and harden off before cold temperatures arrive.

"There is less competition from weeds in the fall because a lot of the annual weeds are dying out," he said. "Plus, we are usually blessed with cool temperatures in the fall, which is great for growing grass.

His tips for a good lawn are to dig the soil to at least six to eight inches deep, spread grass seed over the area and tamp it down. Keep the soil moist until germination and also cover with weed-free straw to conserve moisture."

For sod, he says water the new sod several times a day for one to two weeks until it begins to knit or take hold. Be sure that the water goes down through the thick sod and moistens the soil underneath for good root development. Do not let sod dry out.

To limit those pesky mosquitoes and West Nile virus, he said, "Keep your gutters free of debris because clogged roof gutters make great breeding sites. Clean and freshen pet dishes, wading pools and birdbaths. Cut back tall weeds and grass because they can be hiding places for mosquitoes during the day."

More information on preventing West Nile Virus can be found at www.urbanext.uiuc.edu/westnile/prevention.html.

Wolford also suggests keeping a lookout for the emerald ash borer. The adult borer is a one-half inch long, emerald green, bullet-shaped beetle. In June and July, look for the beetle on the leaves and trunks of ash trees. Female beetles will lay eggs. The eggs will hatch in two weeks and larvae will bore through the bark into the cambium.

Then larvae feed for a few weeks and disable the tree's ability to uptake food and water. Initial symptoms include dieback at the top of the tree. The tree will usually die within two years. For information, visit web.extension.uiuc.edu/cook/blogs/eb104/index.html.

August brings yellow jacket season, and Wolford said, "Yellow jackets are responsible for one-half of all human insect stings. They will also sting more than once. They are often confused with honeybees.

"Yellow jackets have very little hair and have bright yellow and black stripes, while honeybees are covered with pale, fuzzy, yellow hairs and do not have sharply defined stripes. Encounters between humans and yellow jackets most often occur around food."

Open cans of pop or open garbage cans attract yellow jackets, as do perfumes and bright clothing. Chemical controls should be avoided because yellow jackets are a beneficial insect.

"They help to pollinate plants," Wolford said. "Instead of chemicals, keep pop and garbage cans covered with lids. Keep rotting fruit under trees cleaned up and avoid wearing brightly colored clothes.

"Above all, do not try to swat them away with your hands and arms. They will only sting if they are disturbed."

Summer is also time to start the annual watch for the dreaded Japanese beetle. These one half inch long, shiny, green-headed beetles love roses and more than 3,000 other plants. They are usually most active during the warmest part of the day from 10 a.m. to 3 p.m.

"The beetle will skeletonize leaves in a short period of time," he said. "Advertised Japanese beetle traps are not recommended. These may actually attract more beetles and increase plant damage.

"The insecticide Sevin will offer some control, but use should be limited since Sevin will kill bees. Read and follow all label directions. An alternative control is to pick them off by hand and drop them into soapy water."

Powdery mildew arrives in August. This is a very common problem, especially during wet summers and at the end of the growing season.

"Powdery mildew leaves white spots on leaves, shoots, buds and stems," he said. "It really doesn't harm the plant, but it doesn't look good. To avoid mildew, space plants properly for good air circulation. Try to avoid wetting the foliage when watering because that can help to spread the disease. Buy varieties of plants that are resistant to mildew."

For details, call (630) 955-1123.