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 Look
for and remove egg masses of tent caterpillars now through spring.
These clusters of eggs look like shiny blobs of mud surrounding the
twigs. Each egg mass contains hundreds and in some cases thousands
of eggs.
The forest tent caterpillar is the most widely distributed tent
caterpillar. It attacks a variety of trees that vary with the
region. Check any sugar maples, aspen, cherries, apples, oaks,
birch, ash, alder, elm, basswood, or water tupelo trees growing in
your landscape.
Trees may suffer damage when large populations of these caterpillars
devour the majority of the tree’s leaves for several years in a row.
This can result in reduced tree growth, top dieback, and tree
mortality. There are several natural predators of this insect pest
so working with nature is a great way to help reduce damage. Remove
the egg masses found on small twigs that are more easily reached on
smaller trees. After the eggs hatch, look for the caterpillars in a
silken mat, not a tent like the other tent caterpillars. Remove the
young caterpillars from branch tips or squash those resting on the
main stem in the evening or on cool days.
You may also see similar egg masses of the Western or
Eastern tent caterpillars depending on where you live. Their egg
masses look similar to those of the forest tent caterpillar. Remove
the egg masses of these tent caterpillars in spring before the eggs
hatch.
Once the eggs hatch, the caterpillars begin forming a webby tent in
the crotch of the tree. As they feed and grow, the tent expands.
They remain in the tent during the hot part of the day and rainy
weather.
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Knock the tents, caterpillars and all, out of the
tree when the majority of caterpillars are in the tent. Smash or
dump the caterpillars in a can of soapy water.
Do not burn the tents. This old practice is hazardous and the fire
can severely damage the tree, much worse than the insects.
Control is usually not needed on healthy and
established trees. If you decide to intervene, consider using an
organic insecticide with the active ingredient Bacillus
thuringiensis var. kurstaki (Btk). It is effective when applied to
the tents soon after they start to form and when the caterpillars
are small. Just spray the tent and the surrounding 1.5 feet of
leaves. These products only kill caterpillars and will not harm
other insects or birds feeding on these pests.
When working with nature, we have help from predatory insects and
songbirds when managing these and other garden pests. Taking time
this winter for a bit of prevention can go a long way in reducing
damage from tent caterpillars.
Melinda Myers has written more than 20 gardening books, including
the recently released Midwest Gardener’s Handbook, 2nd Edition and
Small Space Gardening. She hosts The Great Courses “How to Grow
Anything” instant video and DVD series and the nationally syndicated
Melinda’s Garden Moment TV & radio program. Myers is a columnist and
contributing editor for Birds & Blooms magazine and her website is
www.MelindaMyers.com.
[Photo courtesy of MelindaMyers.com] |
