No. 3/May 15, 2017
Modified Growing Degree Days (Base 50°F, March 1 through May 11)
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.
Banded Spruce Needles
We received two samples of spruce, one Norway and one White, with a distinctive, brown banding pattern on the needles at the Plant Clinic in the last few weeks. We've seen similar symptoms occasionally over the years, and have never been able to associate the damage with a pathogen or insect pest.
Weather Injury to Plants
Illinois has experienced some interesting weather the last couple of months. March and early April seemed like late spring or early summer. The last couple of weeks have felt more like early spring. Rainfall amounts have hit the double digits for the week ending May 6th in some parts of the state. Needless to say, plants are as confused as we are.
Snakes
Few people like snakes. We might admire them begrudgingly, usually behind an inch-thick piece of glass or Plexiglas. We might attempt to stroke our hands across the snakes back that someone is holding, feeling the coldness to the scales.
Moles
Getting rid of moles is as easy as removing squirrels, and the end result is the same. Once the pesky creature is removed, nature steps in, and nature abhors a vacuum. That means another mole will take its place. Moles are a little different, but somewhat the same. You can battle and battle with the moles, feel you've won, and then find out another moves in.
Insects Susceptible to Control
Insects do not develop at temperatures much below 50 degrees F so they were not developing during the weeks with highs in the 40's and low 50's degree F, but the plants were developing during that time. Although insects were developing somewhat ahead of normal with extra daytime highs above 50 degrees F, they slowed down during the last couple of weeks of abnormally cool weather. They are becoming active at about the same time as in a normal year in northern Illinois, about four days ahead in central Illinois, and about ten days ahead of normal in southern Illinois.
Emerald Ash Borer
Emerald ash borer adults are emerging in southern and central Illinois and will probably do so in northern Illinois in about two weeks. They will continue to emerge over several weeks. Now is the time to apply systemic insecticides to control this pest if emerald ash borer has been found within 15 miles.