Eastern tent caterpillar, freeze effects and gardening calendar

By John Fulton         

[May 07, 2007]  I saw my first small tent from the eastern tent caterpillar this weekend. It happened to be on one of their favorite trees -- an apple tree. Egg hatch may be running as much as three weeks later than normal. Of course, with the crazy "spring" we've had, the insects are probably somewhat disoriented as well.

After hatching, the caterpillars create a white, silken tent in the branch crotches of crab apple, hawthorn, mountain ash, flowering cherry, and other trees and shrubs in the rose family. Eastern tent caterpillar is one of the earliest defoliators. The feeding damage does not kill the tree, but it does use some of the stored energy of the tree.

Control at this time can be accomplished by removing the tents, and the caterpillars inside, and taking them a long way from the tree to dispose of. When caught early, the caterpillars tend to be staying in the nest. As they grow, they will not be in the nest as much. Control with sprays such as Bt, acephate, permethrin and carbaryl will also work.

Effects of the freeze

Some of the effects of the late freeze are easily visible on fruit and shade trees. Trees and shrubs with exposed, tender leaf material (or even swollen buds in some instances) have partially dead leaves. It is common to see leaf tips that are brown on an otherwise healthy leaf. It is amazing there are a few apples set on at least some protected trees. There are even some later blooms coming out. If the bloom centers are brown, it indicates the bloom was damaged and will not set fruit. Some plants had permanently damaged tips, while others are just extremely slow in initiating new buds.

Give things until about the end of May to determine what kind of permanent damage occurred. After that time, dead ends may be trimmed off. Also, keep things as positive as you can for the plants. Water, fertilizer and pest control will probably be as important this year as they have ever been.

Gardening calendar

The gardening calendar shows it is about time, from May 10 to 25, to start in on our tender vegetables. This group includes green beans, sweet corn and tomato plants. It is also time for successive plantings of leaf lettuce, other greens, radishes and spinach. The way the wind has blown, it is probably a good idea to provide some protection for tender transplants for a week or two to let them get established well.

Website

If you haven't checked out our website, give it a look. The site address is www.extension.uiuc.edu/logan. There is an abundance of horticulture information, from local blogs to plant selectors. Most of this is available from the Horticulture and Environment section. This is a good resource to answer questions you might have on many topics. Other sections are available for youth, agriculture, health, money management, kids, teachers and others. There are some great online learning activities for kids, just in time for summer.

[Text from file received from John Fulton, University of Illinois Extension, Logan County Unit]