No. 6/May 29, 2012

Kermes Scale
Kermes scales are occasionally found on pin, white, bur, and other oaks in Illinois. They are most common on or near the branch tips and appear gall-like, so they are commonly misidentified as galls. They also tend to feed in leaf axils, so they are sometimes misidentified as buds. The taxonomy of kermes scale species is uncertain because early work relied heavily on color patterns, which we now know are variable. There are approximately 30 species of kermes that occur in North America, but identification is difficult. This goes beyond academic gymnastics, as different species produce crawlers at different times during the growing season.

Aphids are more noticeable this spring, particularly on linden and tulip poplar, than they have been for many years. Since the late 1990's when multicolored Asian lady beetles became numerous in the state, aphid numbers have tended to be low.

Japanese Beetle
Japanese beetle adults have emerged in Kentucky, so be watchful for emergence in southern Illinois. We continue to see insect emergence about two weeks ahead of schedule throughout Illinois. With emergence in southern Illinois typically occurring around the middle of June, emergence is likely around the end of May.

Hosta Virus X
Hosta virus X (HVX) is a pathogen that has plagued gardeners worldwide. As with most viruses, HVX will not kill hosta; however it can cause a number of undesirable symptoms to appear on the host. HVX is also a difficult virus to pin down because symptoms can often take years to appear in infected hosts, and in some cases no symptoms may ever appear.

Oak Anthracnose
After an abnormally warm, dry spring in Illinois, anthracnose might still be rearing its head. Anthracnose is a disease caused by a variety of fungi, all morphologically similar and with similar symptoms: tan to brown or black lesions on the leaves, stems, flowers, and fruits of various plants. Anthracnose infections occur during rainy, spring weather, and usually subside by mid-summer.

Catchweed Bedstraw -- A Catchy Little Weed
I've had a few queries about catchweed bedstraw lately. Galium aparine is an annual weed that has been quite prevalent this spring. It has a semi-prostrate habit and is commonly found in shaded or wooded areas climbing up over the top of surrounding vegetation. It is primarily found in landscapes, nurseries, small grains, and meadows. It earned the name bedstraw when it was used to minimize matting in mattress filling.