BIOLOGICAL ACTIVITY OF FOUR MINOR NUTRIENT ELEMENTS AGAINST THE NEWLY HATCHED LARVAE OF THE PINK BOLLWORM , PECTIONOPHORA GOSSYIPELLA (SAUND.) LEPIDOPTERA : GELECHIIDAE

The biological activity of four minor nutrient elements, Manganese(Mn) ,Copper (Cu) ,Iron (Fe) and zinc (Zn) was evaluated against the newly hatched larvae of the pink bollworm , Pectionophora gossyipella in a laboratory experiment. The newly hatched larvae were allowed to contact with a residual film at different concentrations of each mineral element until the pupation. The first element Manganese (Mn) was the most toxic one against the newly hatched larvae. The LC50 value was 62.5 ppm , while the fourth element, zinc (Zn) was the least toxic one. Its’ LC50 value was 1200 ppm. The biological activities of the treated larvae were affected. The four tested elements had a similar effect in elongation the larval duration comparing with the control ,while Manganese only significantly increased in the pupal duration and pupal malformation percentages . Whereas, the two treatments, Manganese and Copper showed higher effect than other treatments on most of another biological parameters . Therefore , the pupation and the adult emergence percentages were depressed, and the pupil weight was decreased .Also, the adult fecundity , eggs fertility were inhibited ,and the adult longevity was shortened .While the adult malformation percentages were more pronounced with the copper treatment. On the other side, the Iron treatment had the highest effect on the sex ratio of both adult males and females, it occurred males decreased and female increased, as compared to control, while the copper had an vis versa effect, it gave males increased and decreased in females as compared to the untreated ones.