EFFECTS OF SUB-LETHAL CONCENTRATION OF PHOSPHINE ON THE EGGS AND PUPAE OF RED FLOUR BEETLE: TRIBOLIUM CASTANEUM (HEBST)

The development and mortality of the eggs and pupae of Tribolium castaneum (Hebst)exposed to sub-lethal concentration of phosphine were studied in lab. Treated with low concentrations of phosphine (5 mL/m 3 and 10 mL/m 3), the eggs can hatch and develop, the development time becomes longer, but the mortality of the unhatched eggs is lower than the normal ones. At the little higher concentrations (more than 20 mL/m 3 and 40 mL/m 3) the eggs can't hatch, the death rate is significantly slower than the contrast group. The endurance of the pupae to the phosphine concentration is weaker than that of eggs at sub-lethal concentration, at the same concentration, the mortality is larger and the rate is faster.