L. D. White

Pheromone trap height effect on field catch of codling moth, Cydia pomonella (L.)

Abstract Traps baited with synthetic codling moth, Cydia pomonella (L.), sex pheromone, were positioned at two heights in apple trees, 1.6–2.0 m and 3.5 m, to determine if height significantly influenced trap catch. To eliminate intertrap competition between traps at different heights, the traps were placed alternately high for a week, then low for a week, over an eight week period. Our results showed that the position of the trap in relation of the tree canopy was critical. The trap must be inside the tree canopy. In the absence of intertrap competition between high and low traps, there were no significant differences between catches in traps positioned in the top of the tree or traps at head height. Traps for monitoring codling moth in pest management programs will provide the same information when located where it may be easily reached, as when in the top of the tree.

Control of tropical spotted cutworm, Amathes c‐nigrum (L), by gamma radiation

Abstract The longevity of adult male tropical spotted cutworm, Amathes c‐nigrum (L.) was not significantly affected when irradiated with 20, 30, 40 or 50 krad in air, and 50, 60 or 75 krad in nitrogen. However, the longevity of treated females was significantly increased at 40–50 krad in air and 50–75 krad in nitrogen. Fecundity was significantly reduced when males or females were treated with 20 krad or above in air and 50 krad or above in nitrogen and then crossed with untreated adults. Oviposition by untreated females, mated with treated males at 50 krad in air or 75 krad in nitrogen, was reduced by about 53%, while in treated females crossed with untreated males it was about 96%, at either dose levels or irradiation atmosphere. Per cent egg hatch was significantly reduced at 20 krad or above in air and 50 krad or above in nitrogen when the treated males or females were paired with untreated adults. Complete sterility (no egg hatch) was induced in treated males at 50 krad in air and 75 krad in nitrogen...