Novel Toxicity of Bacillus thuringiensis Strains against the Melon Fruit Fly, Bactrocera cucurbitae (Diptera: Tephritidae)

TY - JOUR

T1 - Novel Toxicity of Bacillus thuringiensis Strains against the Melon Fruit Fly, Bactrocera cucurbitae (Diptera: Tephritidae)

AU - Shishir , Md Asaduzzaman

AU - Akter, Asma

AU - Bodiuzzaman, Md

AU - Hossain, M Aftab

AU - Alam, Md Musfiqul

AU - Khan, Shakil Ahmed

AU - Khan, Shakila Nargis

AU - Hoq, M Mozammel

PY - 2015/6/30

Y1 - 2015/6/30

N2 - Bactrocera cucurbitae (melon fruit fly) is one of the most detrimental vegetable-damaging pests in Bangladesh. The toxicity of Bacillus thuringiensis (Bt) has been reported against a few genera of Bactrocera in addition to numerous other insect species. Bt strains, harbouring cry1A-type genes were, therefore, assayed in vivo against the 3rd instar larvae of B. cucurbitae in this study. The biotype-based prevalence of cry1 and cry1A genes was calculated to be 30.8% and 11.16%, respectively, of the test strains (n=224) while their prevalence was greatest in biotype kurstaki. Though three indigenous Bt strains from biotype kurstaki with close genetic relationship exhibited higher toxicity, maximum mortalities were recorded for Btk HD-73 (96%) and the indigenous Bt JSc1 (93%). LC50 and LC99 values were determined to be 6.81 and 8.32 for Bt JSc1, 7.30 and 7.92 for Bt SSc2, and 6.99 and 7.67 for Btk HD-73, respectively. The cause of toxicity and its variation among the strains was found to be correlated with the synergistic toxic effects of cry1, cry2, cry3 and cry9 gene products, i.e. relevant Cry proteins. The novel toxicity of the B. thuringiensis strains against B. cucurbitae revealed in the present study thus will help in developing efficient and eco-friendly control measures such as Bt biopesticides and transgenic Bt cucurbits.

AB - Bactrocera cucurbitae (melon fruit fly) is one of the most detrimental vegetable-damaging pests in Bangladesh. The toxicity of Bacillus thuringiensis (Bt) has been reported against a few genera of Bactrocera in addition to numerous other insect species. Bt strains, harbouring cry1A-type genes were, therefore, assayed in vivo against the 3rd instar larvae of B. cucurbitae in this study. The biotype-based prevalence of cry1 and cry1A genes was calculated to be 30.8% and 11.16%, respectively, of the test strains (n=224) while their prevalence was greatest in biotype kurstaki. Though three indigenous Bt strains from biotype kurstaki with close genetic relationship exhibited higher toxicity, maximum mortalities were recorded for Btk HD-73 (96%) and the indigenous Bt JSc1 (93%). LC50 and LC99 values were determined to be 6.81 and 8.32 for Bt JSc1, 7.30 and 7.92 for Bt SSc2, and 6.99 and 7.67 for Btk HD-73, respectively. The cause of toxicity and its variation among the strains was found to be correlated with the synergistic toxic effects of cry1, cry2, cry3 and cry9 gene products, i.e. relevant Cry proteins. The novel toxicity of the B. thuringiensis strains against B. cucurbitae revealed in the present study thus will help in developing efficient and eco-friendly control measures such as Bt biopesticides and transgenic Bt cucurbits.

KW - Bacillus thuringiensis

KW - Biopesticides

KW - Insecticide

KW - Endotoxin

KW - Cry protein

KW - Synergistic toxicity

KW - Pest management

U2 - https://doi.org/10.4265/bio.20.115

DO - https://doi.org/10.4265/bio.20.115

M3 - Article

SN - 1884-0225

VL - 20

SP - 115

JO - Biocontrol Science

JF - Biocontrol Science

IS - 2

ER -