Caterpillar

Spongy moth (Lymantria dispar), formally known as the gypsy moth, is still in its feeding frenzy stage in NW Ohio. Caterpillars can very evident when populations increase, and the leaves and needles of host plants disappear as the hungry caterpillars cause defoliation.

Whenever I hear that the naturally occurring biological insecticide Bacillus thuringiensis var. kurstaki (Btk) is not killing caterpillars, the first thing I try to find out is whether or not the "caterpillars" are actually caterpillars. Btk products (e.g. Dipel, Thuricide, etc.) only kill caterpillars, they do not kill sawfly larvae.

The accumulated Growing Degree Days (GDD) that predicts eastern tent caterpillar (ETC) (Malacosoma americanum) egg hatch is 92.  Cincinnati has reached 89 GDD meaning that ETC eggs are poised to begin hatching in southwest Ohio.  ETC spends the winter in shiny, blackish-brown egg masses wrapped around twigs on their host plants.  A close examination will reveal that the eggs are encased in a structure that resembles bubble-wrap.

 

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