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Tent Caterpillars

Les Harrison
Ag & Natural Resources Agent
County Extension Director
UF/IFAS Wakulla County Extension

The recent cold snap in Wakulla County has brought the insect and bug population to a standstill.

The mosquito activity is all in south Florida where a fresh batch of northern tourist is available daily for feasting.  It is safe to stroll outside, in most area locations, without fear of needing a blood transfusion.

Though at a momentary standstill, the signs for next spring’s insect outbreak are evident now. Eastern Tent Caterpillar nest are dropping from trees and being distributed by wind, animals and people.

These native caterpillars build large, thick nests in the forks and crotches of many kinds of trees, especially cherry. The silky tent shaped nests are easy to identity on the upper branches of host trees.

The caterpillars which emerge in the spring of 2013 were laid in the spring of 2012. The adult moth lays her eggs in a single batch in May to July in Wakulla County. There are 200 to 300 eggs laid in the group.

The mass of eggs are shiny, reddish-brown and look like dried foam.  They are ordinarily about six inches back from the tip of a thin twig in host tree.

In approximately three weeks the eggs contain fully formed caterpillars, but the small caterpillars remain in the eggs until the following spring.

In late-February to mid-March they chew their way through their egg shells ready to eat as their host tree is in spring bud.

The voracious larvae immediately infest and, if in sufficient numbers, defoliate oak, plum and poplar. Normally the trees recover after a few weeks, but weakened or diseased trees may die.

When not eating the newly hatched caterpillars construct their silk tent. The caterpillars use a pheromone trail to guild them back home when feeding is done.

A social insect, the eastern tent caterpillars congregate at their specific tent during the night and in rainy weather, expanding it to accommodate their growing size.  These caterpillars do not feed within their nests, keeping it clean and neat.

The caterpillars disperse colonize new areas when maturity is reached.  They construct cocoons in protected places once they have sufficiently scattered.

Birds are not attracted to these hairy caterpillars.  If they have a heavy concentration of black cherry leaves in their diet, the caterpillars will have a bitter acrid taste.

Parasitic wasp and weather are the two most common causes of caterpillar death.  These caterpillars are especially susceptible to cold weather once they have emerged from their eggs.

About two weeks later an adult moth emerges to begin the process again.  Mating and egg laying commonly occur within 24 hours of the moths emerging from their cocoons

The moths are nocturnal and are encountered inflight only at night.   The females die soon after the eggs are deposited.

Contact your UF/IFAS Wakulla County Extension Office at 850-926-3931 or http://blogs.ifas.ufl.edu/wakullaco/ to learn more about Wakulla County’s Eastern Tent Caterpillars.

 

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