Abstract: 【Aim】To develop an efficient mating disruption technique for Helicoverpa armigera and to explore the changes of the calling and mating behaviors, number of eggs laid and egg hatching rate of H. armigera under high-dose sex pheromone environment. 【Methods】 In the laboratory wind tunnel, an active aerosol dispenser was set up to release high-dose sex pheromones at regular intervals. Four treatments were provided, including the complete sex pheromone blend of H. armigera (Z11-16∶Ald∶Z9-16∶Ald=10∶1) and single sex pheromone components Z11-16∶Ald, Z11-16∶OH and Z9-16∶Ald. The complete sex pheromone blend of H. armigera was sprayed once at the intervals of 20, 10 and 5 min, and the spraying interval of the three single sex pheromone components was 5 min. The total duration of sex pheromone spraying treatment was 12 h (from 16:00 to 4:00 of the next day). The calling and mating behaviors of female H. armigera moths, the number of eggs laid and their hatching rates were observed and compared. 【Results】In the high-dose complete sex pheromone blend environment, the calling onset time of female H. armigera moths was delayed in both day-old age and circadian rhythm, and the proportion of female adults extending ovipositor also decreased, as compared with those in the control (in the environment without sex pheromone). The duration of ovipositor extrusion of female moths significantly differed only at the 5-day-old when the complete sex pheromone blend was sprayed at the intervals of 10 and 5 min, but the onset time of ovipositor extrusion of female moths significantly differed at the 1-day-old when the complete sex pheromone blend was sprayed at the intervals of 20, 10 and 5 min. The average mating rate in the control group without sex pheromones was 84.0%±2.1%, as compared with that (5.0%-17.5%) in the complete sex pheromone blend treatment group. The onset age of mating in the complete sex pheromone blend treatment group was also delayed by 1-5-2-day-old as compared with that in the control group. In the experiment of single-component sex pheromone tests, the mating rate of the control group was 88.0%±3.7%, while the single sex pheromone components Z11-16∶Ald and Z11-16∶OH had significant effects on the mating rates, which were suppressed to only 14.0%±4.0% and 14.0%±2.4%, respectively, while the inhibitory effect of Z9-16∶Ald on the mating rate was minor, with the mating rate of 73.3%±3.3%, and  Z11-16∶Ald delayed the onset age of mating by 1.5-day-old, and the effect of Z11-16∶OH and Z9-16∶Ald on the onset age of mating was not obvious. Both the complete sex pheromone blend and single sex pheromone components significantly inhibited the number of matings of female moths (resulted in reduction by 1.3-1.5 times). In the high-dose sex pheromone environment, the egg-laying time of female moths was significantly delayed by 2 d and the average number of eggs laid by mated female moth decreased, but the egg hatching rate of the mated female moths showed no significant change as compared with those in the control. 【Conclusion】The high-dose sex pheromone environment significantly inhibited the calling and mating behaviors of female moths of H. armigera, which further confirmed the autodetection ability of female moths to sex pheromones. By inhibiting calling and mating, sex pheromones delay the mating and oviposition day-old age of female moths of H. armigera, resulting in decreases in the number of eggs laid and hatching rate. The synthetic sex pheromone released by the active aerosol not only prevents the behavioral orientation response of male moths of H. armigera to female moths, but also affects the calling of female moths, and inhibits and delays the mating with male moths, resulting in a decrease in the number of egg laid. Therefore, it may have the potential for higher control efficacy when used in the field.

Key words:  Helicoverpa armigera, high-dose sex pheromones, calling, mating, oviposition