No. 12/August 1, 2017
Syrphid Fly
Large numbers of syrphid, or flower, flies are being seen. They are small flies, usually 1/4 inch or shorter, with yellow and black or brown bands on the abdomen. They hover around your arms when you have been perspiring and land to lap up the sweat. They are called flower flies because they are commonly found on flowers, pollinating as they move from flower to flower. They are called syrphid flies because they are in the fly family Syrphidae.
Chinch Bug
Chinch bug damage is being found throughout Illinois. Numbers of chinch bugs build under drier conditions, allowing bugs to survive which would be killed by fungal disease under higher rainfall. Thatchy turf allows the bugs to escape fungus attack by living in the thatch, not coming into contact with the soil where the fungus is living.
Fall Webworm
Fall webworm is numerous throughout the state, particularly southern and central Illinois. It lives as a group of caterpillars that spin a communal silk web. This silk nest typically encloses the end of the branch and associated leaves. The caterpillars remain in the webbing, feeding on these enclosed leaves. When the leaves inside the web are eaten, the silk webbing is expanded to include more leaves. Webs of mature caterpillars are typically 2 to 3 feet long.
Mimosa Webworm
Mimosa webworm damage is becoming apparent on honey locust throughout the state and on silk tree or mimosa in southern Illinois. The second generation of this insect webs several compound leaves together and then window-feeds on the leaves, causing the leaves to turn brown. This damage is obvious when the webworm is numerous.
Powdery Mildew on Herbaceous Ornamentals
As the season progresses we start to see powdery mildew appear on herbaceous ornamental plants. Common hosts include phlox, peony, bee balm, zinnia, and many more. There are over a thousand species of fungi that cause powdery mildews on a wide range of hosts. Most are fairly host specific.