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The Gypsy Moth Problem in Yellow Springs

"Remember, the Gypsy Moth is a Tree problem, not just a forest problem. Street trees, yard trees, park trees, nursery plants (not just trees, but about 500 plants in the Eastern U.S.) etc., are all potential hosts and food sources for the Gypsy Moth larvae and caterpillar." 

Jim Mickey, Ohio Department of Agriculture

The Gypsy moth is a relatively new problem in Ohio. It is native to Europe and Asia and was introduced into the US in 1860 when several caterpillars escaped captivity in Boston. It quickly became established in Massachusetts . and is now found in many parts of eastern and mid-western US. It has colonized Ohio on two fronts, spreading from Pennsylvania in the east and from Michigan in the northwest. It is unrealistic to expect to eradicate the gypsy moth, but programs such as Slow the Spread (STS) have been very successful. (23) Ohio currently has 39 counties that are under quarantine because of Gypsy moths, 4 of which were added in 2001. Green County is only 2 counties away from Licking County which is one of the quarantined counties. (21)

The Gypsy moth feeds on leaves of more than 300 species of trees and shrubs. The favorite food source is the oak. However they also feed on aspen, birch, lindens sweetgum, crabapple, mountain ash, cherry, hawthorn, pine, spruce and willows. In 1999 approximately 50,000 acres were defoliated. One egg mass (1-1/2" long) can hatch 500-1000 caterpillars. The egg masses can be laid in any outdoor crevice - wood piles, underside of vehicles, outdoor furniture, playground equipment, and permanent trash heaps like junk cars.

The STS program focuses on the transition zone or those areas between the infected and non-infected areas. As the moths spread south and west across Ohio, traps have been placed in areas ahead of the spread. If a specific number of male moths are found in the traps, these areas are called "hot spots." We had some "hot spots" in Clark and Greene counties last year. It has been shown in other parts of the state that if these "hot spots" can be treated and the moths killed or prevented from mating effectively, the spread of the pest can be slowed substantially. The areas that have been targeted are 1.163 acres near Springfield, 207 acres near Clifton, and 3,973 acres in and around Yellow Springs.

Process for determining a problem exists

- Populations should be well delimited (i.e. at least 9 traps per square mile)

- Area is tested with traps for several years to check trends

- If the number of moths found in a trap are greater than 5 it is considered a hot spot (16)

How do they determine the treatment area with pheromones?

- Traps should capture no greater than 30 moths per trap with an average of less that 15 per trap in the year before treatment. Pheromones do not work on large populations of moths because in areas of large infestation the males will find the females regardless of the luring away with pheromones. (8) The Yellow Springs/Glen Helen area meets these requirements with the exception of one trap which captured 38 male moths in 2000. Jim Mickey, Ohio Dept. of Agriculture, told me that he thought one of the hot spots in Yellow Springs was along the creek next to the Bryan Center.

- The treatment should extend at least 5 miles from a source of large numbers of migrating male moths. (22)

- Treatment areas should be large enough to offset male migration. (2500 feet on a side). (22)

Ohio Department of Agriculture Suggested Treatment

- Disrupt II is an aerially applied controlled release product that emits disparlure, a synthetic gypsy moth sex pheromone. Disparlure is incorporated into plastic laminated flakes designed to release the pheromone over a period of 3 to 4 months, during the time of male moth flight. When applied as directed to the tree canopy, the product saturates the air in the treated area with a low but effective concentration of the artificial pheromone. The pheromone emitted by the tiny flake (1/32" x 3/32") effectively disrupts the communication between the female and male gypsy moths and prevents the males from finding and mating with the female moths. The quantity released is approximately equivalent to 1 cup of flakes per acre or the equivalent of 4-5 flakes per square foot. (18)

- The flakes are mixed with diatomaceous earth (3% by weight) to prevent clumping. (7)

- Release of the flakes is closely regulated based on wind speed and direction, rainfall and temperature. The release is scheduled to take place in early July. It is released at daybreak, from a plane flying 50 feet above the tree line.

What Happens If We Do Not Slow The Spread?

Defoliation does not always kill the trees. As a rule, a healthy tree can tolerate three years of defoliation before it is killed. Defoliation does decrease the energy reserves of the tree and reduces its ability to resist disease and insect pests. Defoliation also makes the tree much more susceptible to the effects of drought. Evergreens are frequently killed with only one severe defoliation. (1)

Yellow Springs is in the transition Zone. It is predicted that if we do not Slow the Spread, most of Ohio will be infested by the moth by 2005. By implementing the STS management program the territory invaded by the gypsy moth is expected to decrease by 60% or approximately decrease from 15,600 square miles per year to 6,000 square miles per year. (11)

Negative effects of the Gypsy Moths on Humans and the Environment

- Gypsy moth outbreaks have been associated with adverse human health effects including skin lesions, eye irritation, and respiratory reactions. (USDA 1955, Vol. II p4-9)(6)

- They also have a negative effect on the Northern Tiger Swallowtail butterfly. (3) There is also the problem of inhaling feces droppings in areas of large infestation.

- It is recommended to wear gloves when collecting the egg masses, as people's skin is often irritated by the fine hairs covering the egg sacs. If using the burlap on trees it is recommended to use forceps or wear rubber gloves when collecting the caterpillars.

Here are our reports on [pheromones], [fungus], [virus], [wasps], [bacteria], [pros and cons] .

The Village Manager Rob Hillard spoke on his experience using wasps to reduce Gypsy Moth populations.

We have placed our research information in the Yellow Springs Library to aid you in coming to your own conclusion.