The results of the pheromone test are shown in Table 3. At the high dose rate, the two formu- lations did not differ in ability to reduce mating (95% for the 1976-NCR formulation vs. 97% for the 1978-NCR formulation) or trap catch (88% vs. 86°70, respectively). At the rate of 5 g disparlure per hectare, the 1978-NCR-2 formulation reduced mating 76% and trap catch 34%.

Mating Disruption Achieved by Use of Three-Layer NPA Pheromones

The three-layer laminated polymeric dispenser has been adopted for use in gypsy moth traps.“ Similar dispensers have been used to suppress mating of other insect species. Such dispensers are placed in a checkerboard grid over the infested area,“ a procedure that has now been adapted for use in attempts to disrupt gypsy moth mating. The dispenser produces an almost constant release of pheromone for an extended period; also. given constant conditions of temperature and wind speed, the rate of release of disparlure depends on the polymer composition. the dimensions of the dispenser, and the pheromone loading.” In initial experiments, the dispensers were deployed.

The laminated material was cut into uniformly sized flakes that were fed dry from a hopper on the aircraft wing to a conical distributor where they were mixed with sticker. This material appears to be superior in performance to the formulations tested in 1976 and shows promise for large—scale application. Rates of 50 g disparlure per hectare provided a high degree of mating reduction in field tests in 1979. Learn about NPA New Pheromone Additive | and

Pheromones Mating Disruption Studies

Until 1974, most tests were conducted on relatively large plots (16 ha and above). Then Granett and Doane” examined the value of small plots (1 ha) for measurement of disparlure—mediated reduction of male mating potential. They applied microencapsulated disparlure by knapsack mist blower to 1—ha replicated circular plots in three areas in Connecticut with population densities in the three areas estimated at 0, 40, and 1470 egg masses per hectare. Plots with 40 egg masses were treated twice with 18 g disparlure. The other two areas were treated only once. The results were measured by reduction of male catch in disparlure—baited traps and by deploying virgin female moths (field-collected pupae) in the treated area. Learn more at

Trap catches in treated plots were depressed more than 98% below those in the control plots. None of the females placed in the treated plots were mated, but 74°70 were mated in control plots. This trap catch in the field could be correlated with mating potential, and there appeared to be little movement of ‘males into the treated plots. Thus, it even appeared that disparlure had some potential for reduction of dense pop- ulations. However, the same result was not obtained in subsequent years. In fact, these tests and several others with disparlure have given results that are not fully understood, especially when the experiments have been conducted in heavily infested areas. Perhaps when population dynamics are better understood and the interaction of factors such as disease, climate. and predator populations can be quantitatively assessed, it may be possible to predict the effect of mating reduction mediated by behavior-modifying chemicals on the growth or decline of an infestation. Until that time. biological effects