larval dipping method was adopted for
the toxicity bioassay of B. longissima. The formulated
insecticides were diluted with acetone water (1
19 by volume). The Þve concentrations series in geometric
grade ranging from no effect to 100% lethal
concentration were set after range Þnding experiments.
Approximately 15 3-d-old fourth-instar larvae
from the populations were dipped in serial solutions
for gentle shaking 5 s. The larvae were taken out on