Action thresholds of Empoasca terminalis (Homoptera: Cicadellidae) on soybean in South Sulawesi, Indonesia

Abstract

Empoasca terminalis Dist. (Homoptera: Cicadellidae) is a new but increasingly important pest of soybean in South Sulawesi province of Indonesia. Farmers are dependent mostly upon insecticide use for the control of the leafhopper. Insecticide is applied on a schedule basis, usually once in 2-3 days and not on the basis of action thresholds. Action threshold is used to prevent over-treatment and under-treatment of the intended crops. Therefore, the purpose of the current study was to determine the action thresholds of E. terminalis on two varieties with different levels of resistance to the insect: Mahameru (susceptible) and Gepak Kuning (resistant). Besides that, it was also sought to know the number of insecticide applications required for each action threshold on each variety. Results showed that the action thresholds of E. terminalis were 10 and 5 nymphs per 16 leaves for resistant and susceptible cultivars, respectively. On Mahameru and Gepak Kuning the numbers of insecticide applications necessary to maintain the action thresholds were 5-7 and 1-2 times during the season, respectively. Therefore, total number of insecticide applications based on the action thresholds can be reduced substantially in comparison with the farmers practice which is one application for every 2-3 days or up to 16 applications during the season.