Influence of mixed biocide GCSC‐BtA on the pupae and adult stages of Apanteles plutellae Kurd. (Hym., Braconidae) and its host. 
Plutella xylostella (L.) (Lep., Plutellidae)

Abstract

This paper deals with the influence of the mixed biocide GCSC‐BtA on the pupal and adult stages of Apanteles plutellae Kurd. (Hym., Braconidae) and its host, Plutella xylostella (L.) (Lep., Plutellidae). The results show that mortalities of the pupae of P. xylostella in the direct‐dip bioassay were 84.67 %, that of the adults in the residue bioassay at 1.2500 mg/ml concentration of GCSC‐BtA were 78.00 % which were significantly higher than the mortality values for the pupae with 54.62 % and adults with 48.13 % of A. plutellae. In contrast, cypermethrin showed extremely high toxicity to the pupae with 94.58 % and adults with 86.00 % mortality values of A. plutellae as compared to the low mortality values of 42.14 % for the pupae and 32.11 % for the adults of P. xylostella, with the same concentrations and bioassay methods. The LC50 values of GCSC‐BtA were 0.3402, 0.5516 and 1.2405, 1.9480 mg/ml for the pupae and adults of P. xylostella and A. plutellae, respectively, while the LC50 values for cypermethrin were 1.5652, 2.3471 and 0.1096, 0.1152 mg/ml, respectively. GCSC‐BtA was found more toxic to the pupae and adults of P. xylostella and safer to the pupae and adults of A. plutellae than cypermethrin. The possibilty of using GCSC‐BtA against P. xylostella under partial control by A. plutellae in vegetable fields is discussed.

Investigations on side‐effects of the mixed biocide GCSC‐BtA on different predators of Plutella xylostella (L.) (Lep., Plutellidae) in southeastern China

“…The results of the bioassay experiments showed that GCSC‐BtA had high efficacy in controlling the pest P. xylostella and relatively low toxicity to its predators A. longispinosus, E. graminicola, O. similis and C. septempunctata . High efficacy of GCSC‐BtA against P. xylostella and low toxicity to its parasitoid, Apanteles plutellae Kurd has been reported earlier ( Sengonca and Liu , 2001; Sengonca et al., 2001). However, selectivity of GCSC‐BtA to the predators has been evaluated for the first time in the present experiments.…”

“…A new idea of multiple‐toxin has been worked out to conjugate the toxin of Bacillus thuringiensis (B. t.) with the toxin of Abamectin, which is produced by fermentation of Streptomyces avermitilis, to form a new type of mixed biocide called GCSC‐BtA. It has resulted in enhancing control efficacy in a wide host range of target pests ( Sengonca and Liu , 2001). Efficiency of GCSC‐BtA in controlling vegetable pests in different insect orders has been proved ( Sengonca et al., 2001).…”

Conjugation of δ‐endotoxin from Bacillus thuringiensis with abamectin of Streptomyces avermitilis as a new type of biocide, GCSC‐BtA, for control of agricultural insect pests

“…preparation (HD‐1) under the same conditions ( Sengonca et al., 2001). Comparative research in cabbage fields gave full proof of the efficiency of GCSC‐BtA in controlling P. xylostella (83.60 %) and Brevicoryne brassicae (L.) (Hom., Aphididae) (97.05 %) ( Sengonca and Liu , 2001). Investigations on side‐effects of the biocide GCSC‐BtA on different predators of P. xylostella revealed that the component had high efficacy in controlling the pest with less impact to its predators ( Liu and Sengonca , 2002).…”

Conserving the efficacy of insecticides against Plutella xylostella (L.) (Lep., Plutellidae)

“…These findings suggest that C. plutellae is equally effective in controlling Bt ‐resistant DBM on genetically modified Bt plants and wild‐type plants ( Schuler et al., 1999, 2003, 2004). A mixed biocide GCSC‐ Bt A ( Bt toxins + Abamectin) was found toxic to DBM (92.18% mortality) in the south‐eastern China and safer to pupa and adult stages of C. plutellae ( Sengonca and Liu , 2001; Sengonca et al., 2001). The recommended field concentrations (1200 mg a.i./l) of commercial Bt ‐insecticides (e.g.…”