In the plot treated with pheromones-impregnated hydrophobic paper, none of the released males was recaptured in releases as long as 25 days after treatment.

Similarly encouraging results were obtained in subsequent pre-season tests on Cape Cod, Massachusetts, this time using virgin female moths as bait in some traps and pheromones in others (Stevens and Beroza 1972). However, field tests in naturally infested areas of eastern Pennsylvania in the summer of 1971 failed to demonstrate suppression of mating through application of pheromones on either the hydrophobic paper or on granular cork. It is probable that study sites supported gypsy moth populations which exceeded the upper level at which the disruption technique may eventually be shown to be operational (Cameron 1971). In addition, these tests convinced us that we needed much more knowledge of behavior of adults of both sexes of the insect.

Following further successful pre-season testing on Dauphin Island in 1972 by USDA personnel, larger field tests of the disruption technique were undertaken in central Pennsylvania during the normal flight season in the summer of 1972. Wild insects were placed in 100-hectare study areas, treated with pheromones-impregnated granular cork applied by aircraft, to simulate incipient populations. Approximately 622 g cork, containing either 7.5 or 25 g pheromones, were applied per hectare. In all tests, the proportions of female moths fertilized were reduced, and in two of the four tests these reductions, compared with untreated check plots, were statistically highly significant (Cameron 1973). However, because of the reproductive pheromone potential of the gypsy moth, the reductions were not considered to be biologically significant since they would not cause a downward trend if a natural population of the same size had been allowed to persist through another year.  Learn about the sexiest pheromone perfumes |

Late in August, yet another test of the disruption technique was conducted. A microencapsulated formulation of pheromones was aerially applied to two 100-hec- tare test plots at a rate of 5 g pheromones per hectare*. A sticker was incorporated into the formulation to achieve stratification of the microcapsules throughout the vertical profile of the forest. Laboratory-reared pupae were placed as before to simulate an incipient infestation. During the 12 days of the test, we were unable to detect evidence that even one female in a treated plot was mated. When compared with results from the untreated check plots, these differences were both statistically and biologically significant. Post-season tests with microencapsulated pheormone formulations on Cape Cod by USDA personnel gave similarly encouraging results. Tests in 1973, using both laboratory-reared and wild insects, and applying microencapsulated dis- parture at rates of 2.5-15 g per hectare, substantiated results obtained during 1972 (Cameron et al. 1973a; Schwalbe et al. 1973).

Behaviorally, we know far too little about adult gypsy moths of both sexes. At this point, we do not understand the mechanism by which disruption of response. Learn more about pheromones at

* The formulation was developed by M. Beroza. using a microencapsulation process developed hy the Capsular Products Division of National (Tush Register Co.. Miamisburg, Ohio 45342.