No. 10/June 29, 2015

Crabapple Scab
Apple Scab is an extremely common fungal disease of apple and crabapple caused by the pathogen Venturia inaequalis. Early symptoms of the disease appear as olive green spots on the foliage.  The spots often form along or near the leaf veins, eventually developing a dark, velvety appearance. Infected leaves also may appear curled or puckered. 

Wet Weather Turf Pests
The heavy rainfall this spring is conducive to high numbers of crayfish, millipedes, centipedes, sowbugs, springtails, fungus gnats, slugs, and earwigs. All of these animals are more numerous in areas with high amounts of dead organic matter and moisture.

Millipedes are elongated, many-legged, hard-shelled, brownish, slow-moving insect relatives that feed on decaying plant material in moist situations. They have two pairs of legs per segment, totaling over one hundred legs per animal.

Centipedes are elongated like millipedes, but have only one pair of legs per segment and are fast-moving. They have one pair of obvious antennae. The last pair of legs are elongated and extend behind as they move.

Sowbugs and pillbugs look like tiny armadillos and are commonly called roly-polies. Pillbugs roll up into a tight ball when disturbed. Sowbugs are flattened dorso-ventrally, with their upper surface consisting of wide plates connected by the underlying body.

Springtails are tiny, jumping insects associated with turf, mulch, and nearby areas. Most species are one-sixteenth to one-eighth inch long, although there are some giants that approach one-quarter of an inch.

Fungus Gnats
Dark winged fungus gnat larvae, Family Sciaridae, feed on decaying organic matter in the soil. When full grown, they are about 3/8 inch long, slender, wormlike, and clear with black head capsules. In very moist to wet conditions, they sometimes migrate in rope-like masses across turf or pavement to pupate.

Slugs are shell-less snails that feed on dead organic matter in moist environments. They are soft-bodied with two pairs of tentacles. The upper, longer pair are optic tentacles with eyes on the tips. There is also a shorter pair near the ground that are sensory tentacles for feeling and smelling.

Earwigs are about five-eighths inch long and reddish-brown with large pincers called forceps protruding from the posterior end. These insects are turning from nymphs into adults at this time. As adults, they are much more active, becoming obvious in their activities.

Modified Growing Degree Days (Base 50°F, March 1 through June 25)
Insect development is temperature dependent. We can use degree days to help predict insect emergence and activity. Home, Yard, and Garden readers can use the links in this article with the degree day accumulations listed to determine what insect pests could be active in their area.

Phenology Report for June 19, 2015
Several invasive plant experts from around the state are continuing their series of reports focusing on the phenology of invasive plants in Illinois. The intent of these reports is to provide an update on the development of invasive plants across the state of Illinois--what plants are in bloom, leafing out, setting seed, or senescing in different areas of the state.

Illinois Invasive Species Symposium Recordings Now Available Online
Did you miss the Invasive Species Symposium in May? No worries! Recordings of these presentations are now online.

Invasive Species Spotlight: Spotted Lantern Fly
Today's global economy provides ever increasing opportunities for invasive pests to enter and exit our country. One recent and newsworthy example of such an accidental introduction is that of the spotted lanternfly (Lycorma delicatula), a planthopper (Hemiptera: Fulgoridae) native to Asia, being detected in Berks County, Pennsylvania in September of 2014.