COLUMBUS, OH -- Surveys conducted this winter at Mohican-Memorial State Forest by Ohio Department of Natural Resources (ODNR) foresters reveal tree-damaging concentrations of the non-native gypsy moth. To counteract the threat posed to the forest's unique ecosystem by the invasive moth, affected areas will be treated this spring with a naturally occurring compound that attacks the gypsy moth caterpillar.
A cooperative gypsy moth suppression effort with the Ohio Department of Agriculture (ODA) and the U.S. Forest Service will focus on state lands in the Mohican area at risk of experiencing damaging outbreaks of the insect. Research has shown that repeated years of tree defoliation can lead to oak tree mortality rates as high as 50 percent.
The treatment compound, known by the initials B.t., was first used at Mohican in 1991, and again in 2000, to protect the region's forest resources from defoliations caused by the voracious gypsy moths. While this approach succeeded in protecting trees in infested areas, weather conditions allowed the insect to rebuild its numbers and to once again pose a threat to the forest.
B.t.k., the strain of B.t. used for gypsy moth control, is an approved product for organic gardening and has been widely used for many years as a treatment for gypsy moth infestations. This particular strain of B.t. used is effective in controlling gypsy moth and certain other caterpillars. It is harmless to humans, birds and other animals.
During the past 10 years, the ODNR Division of Forestry has been closely monitoring gypsy moth populations in the area. A naturally occurring fungal pathogen has helped to keep gypsy moth numbers in check in the region's forests, but the fungus has not been effective during the last two years. Hot and dry weather conditions in 1999 limited fungal activity and allowed the gypsy moth to build its numbers to outbreak levels.
Areas targeted for treatment will include those with high gypsy moth concentrations, highly susceptible forest types, and high levels of visitation.
B.t. treatments will not kill all the gypsy moth caterpillars but will protect trees from foliage loss and will maintain tree health.
Managing the gypsy moth will also maintain quality tourism experiences, protect stream quality, and minimize impact to the surrounding private properties.
Questions and input from the public are welcomed. Opportunities for public input will be announced in the near future.