Kesesuaian Ekstrak Piper spp. (Piperaceae) untuk Meningkatkan Toksisitas Ekstrak Tephrosia vogelii terhadap Ulat Krop Kubis, Crocidolomia pavonana

Abstract

Crocidolomia pavonana is one of major pests of Brassica vegetable crops. One of the viable control alternatives against this pest is the use of botanical insecticides. This study was conducted to determine the suitability of extracts of Piper spp. (P. aduncum, P. betle, P. cubeba, P. retrofractum, and P. sarmentosum) to increase the toxicity of Tephrosia vogelii leaf extract against C. pavonana larvae. Plant materials were extracted separately with ethyl acetate and the resulting extracts were tested against second instar larvae C. pavonana using a leaf-dip feeding method. Extract-treated cabbage leaves were provided to the test larvae for 48 hours then the larvae were fed untreated leaves for the following 48 hours. The number of dead larvae was counted daily until day 4 then larval mortality data were subjected to probit analysis. At 96 hours after treatment (HAT), LC50 of T. vogelii, P. aduncum, and P. retrofractum extracts was 0.046%, 0.105%, and 0.125% respectively. The treatment with extracts of P. betle 1%, P. cubeba 0.6%, and P. sarmentosum 1% caused low larval mortality at 72 HAT, i.e. 16.7%, 10%, and 34.4%, respectively. LC50 and LC95 of mixtures of T. vogelii extract with P. aduncum and P. retrofractum extracts were smaller than those of each extract tested separately and the mixtures had synergistic joint action against C. pavonana larvae. Addition of P. sarmentosum extract 0.2% or boiled P. betle aqueous extract 10% somewhat increased the toxicity of T. vogelii extract. Thus, P. aduncum and P. retrofractum extracts are potential to be used in mixtures to increase the toxicity of T. vogelii extract, especially for controlling C. pavonana.