Mating-Inhibition Field Tests Using Disparlure, the Synthetic Gypsy Moth Sex Pheromone12

Abstract

Disparlure-treated hydrophobic filter paper was distributed by aircraft in 40-acre plots at the rate of 20 mg/acre (about 5400 pieces 1/4-in-square/acre, each piece containing about 4 µg of disparlure). For 6 days this treatment almost completely prevented released males of Porthetria dispar (L.) from locating traps baited either with a single live virgin female or with 10 µg of disparlure. Three weeks after applying the lure-treated paper, captures of released male moths in the treated areas, when compared with captures of released moths in untreated areas, were depressed 93 and 67% in plots containing traps baited with live females and disparlure, respectively. The disparlure-baited traps consistently attracted more males than those baited with live females. Traps placed at a height of 1 m generally caught more moths than those placed at a level of 4 to 5 m. Captures of male moths were recorded 1 and 24 hr after release of the males; most captures were made within the 1st hour. The data indicate that the use of disparlure in this manner to prevent gypsy moth mating in very light infestations shows high promise, hut that a disparlure formulation of greater persistence is needed if mating is to be depressed adequately for an entire season with a single application.