Keefektifan Kitosan terhadap Penekanan Infeksi Bean common mosaic virus dan Vektornya, Aphis craccivora Koch., pada Tanaman Kacang Panjang

Abstract

Aphis craccivora is one of important pests on yard long bean. It can cause direct damage and also indirect effect as vector of Bean common mosaic virus (BCMV). The research was done to test the effectiveness of chitosan in suppressing BCMV transmitted by A. craccivora and also its effect on aphids population growth and feeding preference. Chitosan with concentration ranged from 0.1-1% was applied as leaf spraying at 1 day before BCMV transmission. BCMV was transmitted by viruliferous 3 aphids per plant. The incubation period, disease incidence and severity, was observed up to 4 weeks post BCMV transmission. BCMV accumulation was detected serologically at 4 weeks post viral transmission. The effect of chitosan on population and feeding preference of A. craccivora was conducted in laboratory trial using similar chitosan concentrations. Generally, plants treated by chitosan showed lower severity and milder symptom, lower disease incidence and reduced BCMV accumulation significantly in compared with untreated control plants. All treatment plants showed better growth than untreated plants significantly. The chitosan treatments either on the leaves or plants suppressed the population and feeding preferences of A. craccivora significantly in compare to that of untreated ones. These showed the positive effects of chitosan on either suppressing BCMV or A. craccivora population and feeding preference. The suppression of BCMV infection transmitted by aphid might correlate with the antifeedant effect of chitosan on ability of A. craccivora. Based on obtained data, among chitosan concentrations tested, chitosan with concentration 0.9% was the most effective concentration in suppressing BCMV and its vector A. craccivora.