Methods for sex pheromone monitoring and trapping of Apolygus lucorum in apple orchard

Abstract: 【Objective】The occurrence of Apolygus lucorum in apple orchard is increasing. It tremen- dously affects the growth and output of apple trees. A. lucorum can absorb the juice of apple leaves, flowers and young fruits and damage apple leaves and flower buds, and cause fruit deformity or even shedding, resulting in serious economic losses. The application of insect sex pheromone in biological control of insect pests has attracted more and more attention due to its advantages of strong specificity, environmental friendliness, high sensitivity and safety to natural enemies. Rational use of synthetic in- sect sex pheromones for pest control is of great significance in the reduction of the use of pesticides. At present, A. lucorum has been controled using insect sex pheromone mainly by trapping the adult pests. The male adults of A. lucorum are trapped by the traps in the field, reducing the ratio of male to female and the number of adults in the field, thus decreasing the population base of the next generation. Al- though numerous researches have been conducted, there has been no report on the application of insect sex pheromone on A. lucorum in apple orchard. We explored the monitoring technology for A. lucorumby sex pheromone and determined the growth and decline rules of A. lucorum. The best combination of insect sex pheromone and trap was screened out, so as to realize the green control of A. lucorum in ap- ple orchard.【Methods】The insect sex pheromone was used to monitor the occurrence dynamics of A. lucorum in apple orchard and the trapping effects of different hanging heights (1.0 m, 1.5 m, 2.0 m), types of traps (triangle, convex, concave), density of traps (45 per hm2, 90 per hm2, 135 per hm2) and colors of traps (red, yellow, white) on A. lucorum were evaluated. Traps were hanged up on the outside  of the apple tree, and the number of A. lucorum captured in each trap was recorded weekly. The posi- tions of the trap were changed periodically to reduce the error caused by the different insect population density in the orchard.【Results】Three occurrence peaks of A. lucorum in the middle and late growth stages of apple were found on August 12, September 21 and November 4 respectively. During the course of the experiment of the seasonal dynamics of A. lucorum, 19 pests were captured by a single trap on November 4. It reached the second peak on September 21 and then decreased gradually. In the middle and last ten days of October, it flew to the apple orchard to lay eggs for overwintering, and the number increased gradually. After the middle of November, due to the decline of temperature, the num- ber of A. lucorum decreased sharply, and kept stable until the end of November. They were mainly ac- tive in the evening and night. There were 9.92, 9.25 and 12.44 pests trapped by convex, concave and tri- angular traps, respectively. Through statistical analysis, the trapping number of triangular trap was sig- nificantly higher than that of concave trap, while no significant difference was found between the num- ber of pests trapped by the triangular trap and the convex trap (p<0.05). The number of target insects varied with the heights of the traps. The number of target insects was 7.33 when the trap was 1.5 m and 2.0 m above the ground. Their trapping capacity was more than that of the trap set at 1.0m above the ground (p<0.05). When the density of traps was set at 90 per hm2, and the maximum number of pests captured by a single trap was 9.67. There was no significant difference between 90 per hm2 and 45 per hm2, but when the trap density was 135 per hm2, the trapping effect was lower. The trapping amount of 90 per hm2 was significantly higher than that of 135 per hm2 (p<0.05). The colors had no significant ef- fect on the trapping amount of A. lucorum.【Conclusion】The convex traps could be used to monitor theA. lucorum in apple orchard. The proper hanging height of the trap was 1.5-2.0 m and the proper densi- ty of the traps was 90 per hm2 in apple orchard., The results of this study would provide a guidance for the scientific application of A. lucorum sex attractants in apple orchard.