The recent warm, dry weather may mean more insect pest problems. In central Illinois, many days were in the mid-80s, while the normal high is in the high 60s. The heat is accelerating insect development. A major phenology plant, Vanhoutte spirea, came into full bloom in central Illinois near the end of April; around the third week of May is more typical. In northern Illinois, The Morton Arboretum staff is noticing insect pests appearing early as well. Many of us are just settling into the early spring insect pests such as Eastern tent caterpillar, European pine sawfly, and spruce spider mite. Now, we have to think about bronze birch borer, oystershell scale, and gypsy moth.
The dry weather throughout the state will cause more insect pest problems. A major natural control factor for caterpillars, aphids, beetle larvae, and most insects is fungal diseases. They are more prevalent and aggressive in moist, cool weather. The dry weather allows more insects to survive. The only good thing entomologically is that dryness also in-creases the number of predatory and parasitic insects surviving to attack the pests. The bottom line is to be watchful for insect pests to be numerous and early.