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The brown planthopper, Nilaparvata lugens Stål., is a major insect pest causing serious damage to the rice crop in many rice-producing countries. The aim of the study was to determine the inheritance characteristics and realized heritability of resistance to imidacloprid in N. lugens from Banyumas, Central Java Province, Indonesia. The five generations of selection increased the resistance ratio (RR) from 46.20-fold at generation 45 (G45) to 150.39-fold (G49) compared with the laboratory-susceptible population. The LC50 values of imidacloprid for the progeny of reciprocal crosses, F1 and F1’, showed no significant differences, indicating that imidacloprid resistance was inherited autosomally in N. lugens. The degree of dominance (D) values for F1 and F1’ were 0.65 and 0.64, respectively, suggesting that imidacloprid resistance in N. lugens was expressed as an incompletely dominant trait. Chi-square analysis based on the monogenic hypothesis indicated that imidacloprid resistance in N. lugens was polygenic. Furthermore, the estimation realized heritability value (h2) was 0.0893. These results would be useful to determine an effective resistance management strategies in N. lugens.

We have introduced an entomopoxvirus gene encoding a virus enhancing factor (EF) into rice, which resulted in high-level accumulation of the EF in the transgenic plants. The introduced gene was stably inherited in the progeny of the primary transformants, as shown by analysis of their genomic DNA. Bioassays for insect susceptibility to baculovirus infection showed that armyworm larvae feeding on the transgenic rice had increased susceptibility to a Nucleopolyhedrovirus. Thus, introduction of the EF gene into plants can be used as a strategy to increase the effectiveness of baculoviruses in insect pest management.

Many parts of the Calotropis gigantea plant are known to contain bioactive compounds, but leaves contain the most. This study aimed to determine the toxicity and antifeedant activity of C. gigantea leaves against Plutella xylostella. The study was carried out from November 2019 to July 2020. Toxicity was tested using the leaf dipping and spraying methods. Antifeedant activity was tested using a no-choice test and a choice test. Identification of the compound composition of the leaf extract of C. gigantea was carried out at the Integrated Research and Testing Laboratory, Gadjah Mada University. Extract toxicity data obtained were analyzed by Probit analysis. The results showed that the antifeedant activity of C. gigantea leaf extract a no-choice and with choice at each concentration had a significant effect on the consumption of P. xylostella larvae rations. The toxicity (LC50) of the leaf extract of C. gigantea to P. xylostella by the dipping method was 2,958 µgl-1 while the spraying application was 3.944 µgl-1. The composition of chemical compounds contained in the leaf extract of C. gigantea is saponins, alkaloids, flavonoids, tannins, phenols, terpenoids. With the composition of these chemical compounds, the leaf extract of C. gigantea has the potential as a source of vegetable insecticide compounds against P. xylostella.

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