Web caterpillars build tent for shelter
Q. What are the web caterpillars on my roses and how do I get rid of them?
A. They are probably Eastern Tent Caterpillars. Their eggs are brownish and are laid in clusters that encircle pencil-sized branches. Caterpillars usually appear in the spring as leaves emerge. They are usually found on roses, crabapples, hawthorns as well as other trees and shrubs in the rose family. They have a yellowish stripe down their backs. Larvae will gather in a branch fork and spin a web that they will expand over time. The caterpillars leave the web during the day to feed on foliage and return to the tent to shelter at night, and on cloudy days.
While creepy looking, the caterpillars do not bite. Get a good look at the web and confirm that the caterpillars are still present. If possible, remove the web tent at night or on a cloudy day by pruning or tearing the webs. If the caterpillars are still present, insecticidal sprays containing Bacillus thuringiensis (Bt) may be effective. Break up the tent to get the insecticide onto the caterpillars inside.
Q. Why do some people pinch off some growth on their tomatoes, and what exactly is a "sucker"?
A. There are several reasons why one might prune tomato plants. Pruning or thinning helps to allow maximum light penetration on the leaves and good air circulation within the plant. Another reason is to channel the plants energy into producing larger and earlier fruit, rather then foliage.
There are two types of tomato plants, determinate and indeterminate. Determinate varieties are shorter, heavily branched plants that grow only to a determined height. Indeterminate varieties grow and produce leaves and flowers throughout the growing season.
Be aware that determinate plants require little to no pruning. Indeterminate plants however should be pruned to a limited number of stems, usually two or three. Usually these are the stems just above and just below the first flower cluster. The lower stem that is allowed to develop is a sucker.
Suckers are small shoots that grow between a leaf and the main stem. This place is also called the leaf node. Suckers should be removed when small by pinching them off with your fingers. Be careful not to damage the main stem.
The growth of indeterminate plants is only limited by the length of the growing season. Therefore they need lots of space to support their sprawling vines. Tall cages or stakes will be needed to keep them off the ground.
Determinate plants bear their crop all at once making them suitable for canning. Indeterminate varieties will produce their crop over the entire growing season providing a steady supply of tomatoes to snack on.
- Ann Priest
• Provided by Master gardeners through the Master Gardener Answer Desk, Friendship Park Conservatory, Des Plaines. Call (847) 298-3502 or email northcookmg@gmail.com.