Gypsy Moth Status Report -- 1994

The gypsy moth situation in Iowa in 1994 was another good-news-bad-news story.

Good news. The good news is that 10 very small infestations (1 to 10 acres each) discovered in 1992 and sprayed with Bt in 1993 had no caterpillar or moth captures in 1994. This adds to the Iowa Department of Agriculture and Land Stewardship string of successful eradications of the small, isolated infestations of gypsy moth that result from transport into the state on vehicles and nursery stock.

The 10 infestations treated in 1993 were located in north central Iowa (Worth, Hancock, Cerro Gordo, Franklin and Butler counties) and in Polk County (Des Moines and Saylorville). These infestation resulted from the importation in 1991 of infested blue spruce trees from a Pennsylvania nursery.

Possibly good news. An infestation of gypsy moth caterpillars discovered in SE Polk County (Ivy, IA; 6 miles E of Des Moines) in 1993 was sprayed 2 times by helicopter and ground equipment in spring, 1994. This infestation was the result of gypsy moth transport on a private recreational vehicle. Only 1 gypsy moth was captured in 500 traps placed within the 30-acre treated area. This moth was caught very late in the season and the significance of this capture is unknown. At this time, the Department of Agriculture anticipates repeating the high density moth trapping program in 1995, but caterpillar spraying in this area is questionable.

Bad news. This years gypsy moth trapping survey captured 143 moths in 31 different counties. Follow-up investigation by state inspectors lead to the discovery that Iowa had received over 22,000 pieces of infested nursery stock from Zelenka Nursery, Inc. of Grand Haven, MI. The plants were infested with gypsy moth egg masses at the 1 to 5% rate. Infested white pine, Colorado blue spruce and black hills spruce trees were sold in Iowa to large retailers and a large number of independent nursery stock dealers. Sale of some stock had already occurred prior to discovery of the problem, but sales areas and as many out-planting sites as possible were inspected. Some spot treatments of infested nurseries will be done in spring, 1995, and trapping efforts will be increased in counties where infested stock was received in order to detect any new establishments that occurred as a result of this unfortunate event.

Good news with which to finish. The Iowa Department of Agriculture has budgeted for the coming year to increase the number of gypsy moth trappers/inspectors from 12 to 18. They also are in close contact with counterparts in other states to increase compliance and effectiveness of reciprocal inspection agreements and other regulatory actions to prevent future entry of the gypsy moth into Iowa. Dedication and vigilance by state and federal specialists, and the use of a highly successful pheromone trapping program have kept Iowa free of gypsy moth. The departments deserve our support to keep it that way.

Gypsy Moth Captures, 1994

This article originally appeared in the November 11, 1994 issue, pp. 11, 1994 issue, pp. 151-152.


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