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Controlling Forest Tent Caterpillar in Limited Acreage Maple-producing Woodlots 2006

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Project Leaders: P. Smallidge, Extension Forester, Director of the Arnot Forest, Cornell University; P. Weston, Department of Entomology, Cornell University; S. Childs, NYS Extension Maple Specialist, Cornell University

Cooperators: S. VanderMark, St. Lawrence CCE Canton Research Farm; A. Barensfeld, Arnot Reserarch Forest; D. Weed, Schoolyard Sugarbush

Many maple producers operate woodlots smaller than the 15 acres normally required by aerial pesticide applicators to treat for forest tent caterpillar.  Only tolerance-exempt pesticides are legal in woods used for maple syrup production.  forest tent caterpillar is currently a serious defoliator in many places in New York, and poses a serious threat to maple sugar production (maple producers are advised not to tap heavily defoliated trees).  These woodlot owners need proven techniques to limit defoliation due to caterpillars to avoid losing syrup production and markets.  In 2006 experiments to control forest tent caterpillar damage in the sugar bush were attempted at three different locations in New York State, all with limited success. 

Since the forest tent caterpillar are known to move around in the tree during periods of eating then congregating, Tanglefoot sticky traps were placed on the trunks of sugar maple trees.  This technique showed a reduction of about 22% defoliation by restricting the caterpillar movement. 

Caterpillars have been found to follow a pheromone trail when moving between eating and congregating sites.  Several experiments attempted to disrupt movement by placing this pheromone on strings and on the trunks of trees.  The pheromone had no observable effect on caterpillar movement. 

Caterpillars stop eating and pupate at about the same time as when the maple tree growth stops and terminal buds are set. One sixth acre areas of sugarbush were fertilized in early May with 25 and 50 pounds of nitrogen to see if growth could be forced and trees immediately re-foliated beyond the caterpillar damage.  Because of the earlier timing of pupation and sufficient moisture in the woods this summer most trees quickly re-foliated with fertilizer plots showing only small improvement.

Pheromone traps were also used to capture adult moths but not enough were collected to make a serious difference to woodlot populations. 

In conclusion, none of our attempts to control the forest tent caterpillar with sticky traps, trail pheromones, fertilization or attractant pheromones resulted in enough reduction in defoliation to make a positive recommendation for control to a limited acreage maple producer.