Efficiency of the mixed biocide GCSC-BtA against vegetable pests of different arthropod orders in the south-eastern China†

Abstract

The present paper deals with the efficiency of the mixed biocide GCSC-BtA against vegetable pests of five orders of arthropod insects in the south-eastern China, i. e., diamondback moth, Plutella xylostella (L.); green peach aphid, Myzus persicae (Sulzer); yellow-fanded flea beetle, Phyllotreta vittata Fabricius; vegetable leaf miner, Phytomyza nigricornis Macquart; and vegetable spider mite, Tetranychus neocaledonicus Andre. The results show that the mixed biocide GCSC-BtA has a higher efficacy of control against all of the five pests than the commercial biocide B.t. and insecticide Diazinon. GCSC-BtA gave a higher mortality value of 92.18 % against P. xylostella as compared to the biocide B.t. with a value of 64.70 % and Diazinon with a value of 50.00 %. Similar mortalities were obtained with the other four pests regarding the efficacy of the three products tested against them.

The concentration-mortality regression equations were calculated by the probit analysis, from which the average mortalities were calculated. The values calculated for GCSC-BtA were 81.13 % for P. xylostella, 75 % for M. persicae and T. neocaledonicus, 69.23 % for P. vittata, and 61.03 % for P. nigricornis as compared to those caused by Diazinon: 33.33 %, 27.42 %, 66.31 %, 44.54 %, 19.65 % for P. xylostella, M. persicae, P. vittata, P. nigricornis, and T. neocaledonicus, respectively. Based on LC₅₀, P. xylostella was most susceptible to GCSC-BtA with a LC₅₀ value of 0.3445, followed by B.t. with a value of 0.8404 and Diazinon with a value of 1.3160. The LC₅₀ value of GCSC-BtA for M. persicae was 0.4660 which was about three times less than that of Diazinon. LC₅₀ value of GCSC-BtA for P. vittata was 0.3954 which was about the same as that of Diazinon. P. nigricornis and T. neocaledonicus were also much more susceptible to GCSC-BtA than to B.t. and Diazinon. It is concluded that GCSC-BtA kills more target pests than B.t. and is more effective than Diazinon in controlling the vegetable pests.