Toxic activity of Tripterygium wilfordii ethanol extract and its bait against Solenopsis invicta

Objective To study the toxic activity of root bark extract of Tripterygium wilfordii and its bait against Solenopsis invicta worker ants.

Method The active substance was extracted by ethanol from the root bark of T. wilfordii and the bait was prepared. Toxic activities of T. wilfordii ethanol extract and its bait to red imported fire ants were obtained by water tube method.

Result and conclusion After 10 days of treatment, the workers mortality were 6.67%, 30.00%, 56.67% and 70.00% at the extract concentration of 0.023 9, 0.047 8, 0.239 0 and 0.478 0 g·L^-1 respectively, which were significantly higher than that of the mortality of control. The results tested by bait method showed that, unlike the large ant workers, the mortality of small workers was seriously affected by the concentration of the extracts. Treated by 0、0.0478 and 0.095 6 g·L^-1 bait for 10 days, the workers attack rates were 90.00%, 66.67% and 70.00%, grasping rates were 83.33%, 60.00% and 56.67%, climbing rates were 93.33%, 73.33% and 73.33% respectively. The root bark extract of T. wilfordii and bait have good insecticidal activity against red imported fire ants under indoor conditions, which can inhibit the activity ability of red imported fire ants. T. wilfordii is expected to become a new chemical agent to control red imported fire ants.