Field Observation on the Use of Sex Pheromone to Control Spodoptera litura on Soybean in Indonesia

Abstract

The Agricultural Technical Mission-Republic of China to Republic of Indonesia (Surabaya) introduced a total of 35,000 lures of sex-pheromone from the Taiwan Agricultural Chemical and Toxic Substances Research Institute to test and demonstrate the use of sex-pheromone for controlling Spodoptera litura in soybean field in East Java, Indonesia. The field observation and demonstration activities were carried out in 1989-1992. The comparison test of pheromone + chlorpyrifos and chlorpyrifos alone was employed in 1989 at Jombang. Both treatments had very good results on the controlling S. litura, but the application of chlorpyrifos was decreased from 7 times to 4 times when pheromone was used together with chlorpyrifos. The leaf damage by insect was about 15-16% for both treatments. Large scale field observation test was conducted at Gresik and Lamongan in 1991, and Ngawi and Jombang in 1992 with a total acreage of about 270 ha. Three sex-pheromone traps were installed one week after seeding and renewed about 35 days later. An average of 417-615 insect/ha were attracted and killed by these sex-pheromone traps. About 65-75% of insects were captured in the first 5 weeks after sex-pheromone trap installment. The test on the effects of number of traps was employed in 1992 at Jombang. It was found that the insects killed increased from 289 insect/ha in the treatment of 2 trap/ha to 1044 insect/ha in the treatment of 10 trap/ha. The economic analysis also indicated that the use of sex-pheromone could significantly reduce the input of pesticides on soybean production. The cost of pesticide was decreased from NT$ 869/ha of check farmers to NT$ 599/ha of demonstration farmers. The net income on the sex-pheromone demonstration farmers was about 15.7% higher than that of the check farmers.