Fall Webworm, Bagworm and Tent Caterpillars

 

by Karen Weiland, Advanced Master Gardener

 

 

People have nothing on bugs when it comes to using bags and tents for protection while sleeping.  Some caterpillars have similar methods to protect them from the elements and from the voracious appetites of birds.

The Eastern Tent Caterpillar appear early in the season, usually in late April.   You will find their egg masses, which overwinter in this stage, attached to small twigs, and appear as shiny, dark gray foam wrapped around the twig.  The larvae gather at a fork in a tree and build a web-like tent.  Tent Caterpillars like to feed on wild cherry, crabapple, plum and peach to name a few.  One or two colonies can completely defoliate a small tree.  Since this defoliation occurs early in the season, the plant must expend much energy in setting out new leaves thus enhancing the possibility of weakness.  The egg masses are easy to spot in the fall after the leaves have dropped.  Clip them off the twig and crush or dispose of them.  Nests may be hand removed in the spring by scraping it off the tree and onto the ground where they may be crushed or drop the nest into a bucket of soapy water.  Because most caterpillars will be in the nest, late afternoon or early morning is best to remove them from the tree.

The fall webworm appears on trees in late summer and early fall.  Fall webworms enclose leaves and small twigs in their light gray, silky nests which are usually located at the tips of branches.  These larvae have been known to feed on over 85 different species of trees in the United States.  This pest overwinters in the pupal stage in the ground but can also be found in the debris of old nests and under loose bark.  The adults emerge from late May into July.  Nests can be pruned out of small to medium trees.  Parasites and predators. such as wasps, birds, predatory stink bugs and parasitic flies, may control the worms biologically in larger trees where you can’t reach.  If using insecticidal sprays, keep in mind that the spray will be detrimental to the natural predators of the webworms.

Bagworms pass the winter as eggs and hatch in early June.  Bagworms prefer juniper, spruce, arborvitae, pine and cedar but have been known to attack deciduous trees.  Bagworms mature in late August or early September. The caterpillars feed for about six weeks, enlarging the bag as they grow.  Older larvae strip evergreens of their needles and devour whole leaves of deciduous species leaving only the larger veins.  When abundant they can defoliate a plant and heavy infestations over several years, especially when coupled with other stresses such as drought, can kill that plant.  Bagworm caterpillars make 1 ½ to 2 inch spindly bags which are sometimes mistaken for a pine cone or other plant structure.  If only a few plants are affected, handpicking and destroying the attached bags by placing them in a bucket of soapy water may provide sufficient control.  If an insecticide is needed, the best time to apply it would be in the early stages while the larvae are small, usually in early July.  Young bagworms are hard to see at first.  Look for small upright bags that look like tiny ice cream cones made of bits of plant matter.

 

As always, Happy Gardening!

 

More information about gardening and related subjects is available online at http://www.hort.purdue.edu/ext/garden_pubs.html  The Purdue University Cooperative Extension Service can be reached at 499-6334 in LaGrange Co., 636-2111 in Noble Co., 925-2562 in DeKalb Co. and 668-1000 in Steuben Co.

 

Scenic Fall Drive in Shipshewana, Indiana

Typically when you roll into Shipshewana, you’re greeted by endless farms and open fields. It might be surprising to hear of the beautiful fall foliage that can be seen this time of year. The natural beauty here in LaGrange County can often be underappreciated, many people not knowing about hidden gems like the Pigeon River …

Read More >

Caring for your Christmas Cactus

The Christmas Cactus is a popular holiday gift and also a subject of discussion amongst gardeners as to how to care for it and what it takes to make it bloom.  It always helps to know the origin of a plant to understand what makes it tick. This plant is a succulent, tropical type of …

Read More >

Stokes Aster Flowers

When giving some thought recently about fall-blooming, perennial flowers the ever-popular chrysanthemum or mums as they are usually called, was the first to come to mind. However, there is another flower that is a fall bloomer called Aster. There are many different kinds with varying heights and flower colors. They are easy to grow and …

Read More >

Get your official copy of our

Destination Guide

Request Printed Guide

View E-Guide

Stay informed and sign up for the

EMAIL-Newsletter

Sign Up