No. 3/May 9, 2011
Weather Effects on Insect Pests
The cool weather that we have had over the past week have kept insects somewhat at a standstill. Most insects do not develop at temperatures below 50 degrees F. They just sit as in suspended animation, not feeding or growing. Although they do feed and develop at temperatures in the 50's, they do so much slower than when temperatures are in the 70's and 80's.
Oystershell scale feeds on a wide range of trees and shrubs, and is very capable of killing them. It feeds on at least 128 host species found in 19 genera in 12 plant families. This scale is most susceptible to crawler sprays, and crawlers are present and susceptible to control at this time of year.
Invasive Species Awareness Month
Did you know that May is Invasive Species Awareness Month (ISAM)? ISAM provides opportunities for all citizens of Illinois to participate in invasive species awareness events around the state. Events and programs are being held across the state and everyone is encouraged to attend and learn more about invasive species.
In the past few weeks I've received a few phone calls concerning the identity of the purple flowers that are abundant in fields, lawns, and landscapes now. Although there are a couple of weeds they could be, odds are that sea of lavender that you see across the state is really henbit (Lamium amplexicaula).
Watch Out For Anthracnose
Rains have been plentiful and temperatures have been cool. This weather has been ideal for the development of anthracnose on shade trees just as tender leaves are first developing. Anthracnose causes water-soaked leaf spots ranging in color from dark green to brown.