No. 2/May 19, 2023

Modified Growing Degree Days
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 below with the degree day accumulations above to determine what insect pests could be active in their area.

Eastern Tent Caterpillar
Eastern tent caterpillars (Maclacosoma americanum) are native North American pests that can be heavy defoliators. They feed predominately on members of the rose family including crabapple, apple, cherry species, hawthorn, peach, plum species and many others. When feeding, the caterpillars chew from the margin of the leaf inward, leaving the midvein of the leaf behind.

Invasive Bush Honeysuckle in Bloom and Easily Noticed
Exotic bush honeysuckle is in bloom now in central Illinois. While the flowers are fragrant and lovely, this plant is invasive. In fact, it’s regulated by the Illinois Exotic Weed Act. While control is not required by law, removing this plant as soon as possible is advised given how easily it can spread and take over. It can be found in most counties and can tolerate a variety of conditions including wetness, dryness, sun, and shade.

Sycamore Anthracnose
Most of the sycamore trees in east central Illinois have sparse foliage compared to other shade tree species. This is due to anthracnose, a fungal disease that occurs almost every spring. Disease severity is dependent on the weather and is favored by cool and wet conditions.

New Requirement for Residential Barrier Mosquito Treatments in Illinois
A new Illinois law, effective January 1, 2023, aims to protect Illinois residents and pollinators from pesticide residues related to residential mosquito control treatments. Barrier treatments target and control nuisance adult mosquitos by leaving a residual insecticide coating on surfaces where mosquitos rest. Illinois Public Act 102-0916 amended the Illinois Pesticide Act to include additional restrictions and requirements for residential barrier mosquitocide applications.

Use of Restricted Use Pesticides Banned Near Schools
The Illinois Pesticide Act has been amended to ban the application of Restricted Use Pesticides (RUPs) within 500 feet of any school. If the pesticide label is more restrictive, then that should be followed. For specific changes to the Act, please see Public Act 102-0548. While this became effective January 1, 2022, the enforcement rules were recently determined by the Illinois Department of Agriculture.