Activity of deltamethrin on different surfaces against Plodia interpunctella larvae (Lepidoptera Pyralidae).

The knockdown activity after 1, 24 and 48 hr and mortality after 24 and 48 hr against 4 th instar larvae (female, male) of Plodia interpunctella, were evaluated on glass, ceramic tile and porous tile. Groups of 20 larvae were placed for 5 or 15 minutes in an artificially lighted environment at 25±2°C and 60±10% RH. Tests were carried out 24 hr after the treatment. Five replicates were carried out for each test as well as for the control. The highest mean percentages of the knockdown activity were observed, for both sexes, after 1 hr from the contact with the different surfaces. After 15 minutes the highest mean percentage of mortality was observed in female larvae rather than in male (glass: 23% female, 20% male; ceramic tile: 16% female, 10% male).