Abstract: 【Aim】 The biological activity of benzothiazole on Bradysia odoriphaga Yang et Zhang was assessed in the laboratory. 【Methods】 The biological activity of benzothiazole against adults, eggs, larvae and nymphs of B. odoriphaga was detected with fumigation method, the inhibition of benzothiazole on the respiratory rate of B. odoriphaga adults was tested with an Oxytherm system, and the behavioural response of B. odoriphaga adults to benzothiazole was measured with Y-tube olfactometer. 【Results】 The results showed that the LC50 values of benzothiazole against female and male adults were 0.186-0.052 and 0.163-0.039 μL/L at 0.5-2.0 h after treatment, respectively. After fumigation with 0.01-0.13 μL/L benzothiazole for 24 h, the egg hatching rate of B. odoriphaga at 6 d after treatment was 4.83%-82.39%, while that of the control was 96.97%. The LC50 value of benzothiazole against the 4th-instar larvae at 6-72 h after treatment was 1.247-0.248 μL/L. After fumigation with 0.01-0.09 μL/L benzothiazole for 24 h, the eclosion rate of pupae was 8.17%-69.63% at 5 d after treatment, and that of the control was 96.23%. After the female and male adults were treated with 0.052 and 0.039 μL/L benzothiazole for 2.5 h, respectively, their respiratory rates were higher than that of the control group first, then decreased to the comparable level of the control group, and finally were significantly lower than that of the control group. Benzothiazole also showed good luring activity to adults, and the attraction rates to female and male adults were 88.33% and 78.33% at the dose of 0.5 μL at 0.5 L/min air velocity, respectively. 【Conclusion】 Benzothiazole has strong fumigation toxicity to B. odoriphaga at various developmental stages and distinct luring activity to its adults.

Key words:  Bradysia odoriphaga, benzothiazole, fumigation toxicity, respiratory rate, olfactory response