No. 5/May 21, 2010

High populations of aphids have been reported in northeastern Illinois. With warmer, drier weather in the forecast, other areas of the state may see high populations as well in the next couple weeks.

Spider Webs
The high winds in the last couple of weeks have resulting in masses of webbing on turf and trees. When spiders hatch, each disperses by spinning out a long strand of silk, which catches in the wind and allows them to float for long distances to new locations.

Plant Bugs
Fourlined plant bug is a pest on mint, lavendar, sage, artemisia, sunflower, and other herbs. It is particlarly a problem on mint, being its most severe pest. Damage appears as contorted leaves with brown to black spots.

Rose Downy Mildew
We have had a few reports of downy mildew on rose. I doubt home growers will see this problem, but it is something to watch for this spring.

Ivy Leaf Spots
There are commonly two types of leaf diseases on English ivy used as ground covers in landscape beds. We see them both fairly frequently in Illinois. The first is caused by one or more fungi and the other is caused by a bacterium.

Know Your Invasives: Learn to Identify Locally Invasive Plants
During a time of year when gardens are being planted, crops are being cultivated, and yards are being adorned with flowers, it is ever so important to be able to recognize what plants are invasive.

On the Watch for Invasives
In today's era of globalization, the risk of invasive plant pest introductions is increasing. While a central geographic location and a superior transportation system afford Illinois a competitive advantage over many other states, these same factors make Illinois extremely vulnerable to accidentally or purposely introduced exotic pests.