Kerentanan Plutella xylostella dari Kejajar Dieng, Kabupaten Wonosobo, Jawa Tengah lterhadap Lima Jenis Insektisida Komersial dan Ekstrak Buah Piper aduncum

Abstract

Plutella xylostella is an important pest of Brassicaceae vegetable crops that can reduce crop production significantly. In general, farmers use syntethic insecticides intensively to control the pest. However, this control tactic has some negative impacts including resistance in target pests. This study was conducted to determine the susceptibility of P. xylostella from Kejajar Dieng District, Wonosobo Regency, Central Java to five commercial insecticides, i.e. chloranthraniliprole, deltamethrin, emamectin benzoate, profenofos, and spinetoram, as well as Piper aduncum fruit extract as a botanical insecticide for alternative control means. The commercial insecticides and P. aduncum extract were tested against second-instar larvae P. xylostella with a leaf-dip feeding method in which the feeding treatment was given for 48 hours. Larval mortality was counted at 24, 48, 72, and 96 hours after treatment (HAT) and larval mortality data was analyzed with a probit method. Based on LC95 at 96 HAT, deltamethrin and profenofos had low toxicity on P. xylostella larvae. LC95 of these insecticides were 2030 and 8462 mg a.i./L, respectively, which were 203 and 11.3-fold higher than their respective recommended field rates. Meanwhile, P. xylostella larvae were still susceptible to the other three commercial insecticides and P. aduncum extract. LC95 of chlorantraniliprole, emamectin benzoate, and spinetoram were 23.07, 2.59, and 0.90 mg a.i./L, respectively, which were 1.73, 3.86, and 13.33-fold lower than their respective recommended field rates. On the other hand LC95 of P. aduncum extract (2288.39 mg/L) was lower than that of profenofos but was higher than that of the other four commercial insecticides. Meanwhile, LC50 of P. aduncum extract was much lower than that of deltamethrin and profenofos. Thus, P. xylostella from Kejajar Dieng District were not susceptible to deltamethrin and profenofos but still susceptible to the other three commercial insecticides. In addition, P. aduncum extract can be used as an alternative insecticide for the control of P. xylostella. In the treatment with three lowest concentrations, all test insecticides could kill P. xylostella larvae but did not inhibit pupation and adult emergence significantly in the surviving larvae.