No. 6/June 4, 2018
Modified Growing Degree Days (Base 50°F, March 1 through May 31)
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 to determine what insect pests could be active in their area.
Viburnum Leaf Beetles Active in Northeast Illinois
The viburnum leaf beetle, a native to Europe, was brought to North America on infected viburnums. While it is established in several northeastern states, we've only confirmed this pest in a handful of counties in northeast Illinois. If your viburnum plants are showing signs of defoliation, please keep your eyes open for larvae now or Viburnum Leaf Beetle adults during the summer.
Bindweed: The Vines that Bind (to Turf and Ornamentals)
Bindweed is in full bloom in many of the lawns along my regular route. From a distance, it is a pretty little plant. However, if it is growing in your lawn or garden, you may have other less favorable things to say about this persistent and difficult to manage perennial weed.
Rotten Weather and Root Rots
We've received a number of samples with root rot at the Plant Clinic recently. Approximately half have been infected with Pythium, with the other half infected with Rhizoctonia. This is not a huge surprise given the extremely varied weather we've been experiencing.
Suckers and Water Sprouts
Some ornamentals and trees have a tendency to develop numerous epicormic sprouts. These vigorously growing sprouts arise from latent or adventitious buds. Sprouts that form on root tissues are referred to as "suckers," while those that form on stems and branches are termed "water sprouts." The main issues with either of these is that they have poor limb structure, the potential to shade out the main plant, and may even rob the desirable plant tissues of nutrients and water.