Gypsy moth caterpillars on the march

Not all things that hatch out during the spring season are welcome. During early to mid May, gypsy moth caterpillars hatch and emerge from their egg masses. These tiny larvae are very small, about three to five mm, when they first hatch. When they first emerge from an egg mass, they can frequently be seen clustering around the bottom of it.

As these caterpillars grow, they make their presence known by munching on tree leaves and leaving their droppings on the ground, decks, parked cars, etc. In heavily infested areas, the droppings can sound like rain. Trees that are heavily defoliated can usually withstand two to three successive defoliations without dying. However, they will be weakened and susceptible to other pests and weather extremes. New, smaller leaves usually grow by July on recovered trees.

State or county spraying programs, using bacterial agents such as Bacillus thuringiensis var. kurstaki, or BT, vary by region. New York has no spraying program for 2008. In Pennsylvania, Department of Conservation and Natural Resources sprayed 14,025 acres in Pike County last month. More information can be found on the DCNR web page at www.dcnr.state.pa.us/forestry/gypsymoth/index.aspx.