Field assay of sex pheromone of Dendrolimus punctatus Walker was conducted,using ship-shaped traps and rubber septas in forests.In the first year,the average trapping rate was 30.6%,and the average catches were 0.475.In the second year,the test by tripping moth in the forests was carried out with the same batch of sex pheromone septas which stored at low temperature in the refrigerator,the average trapping rate was 25.9% and the average catches were 0.7,showing no influence on the trapping efficiency of the...