ABSORPTION AND RELEASE OF PHEROMONE OF EPIPHYAS-POSTVITTANA (LEPIDOPTERA, TORTRICIDAE) BY APPLE LEAVES

The absorption and release of the pheromone of Epiphyas postvittana (L epidoptera: Tortricidae), E 11-14:OAc and E,E9,11-14:OAc (95:5) by app le leaves was studied using electroantennograms (EAG) and sticky traps baited with pheromone-treated leaves. Leaves exposed to an airstream containing pheromone reached a constant level of pheromone release wit hin 3 min. Release occurred over a period greater than 24 hr, followin g removal of leaves from the pheromone-saturated environment. Pheromon e-treated leaves were effective as lures in sticky traps for at least three nights, although the average catch per night decrease logarithmi cally with time. In the field, pheromone was detected by EAG on leaves harvested from up to 25 cm away from a central point source of pherom one. The shape of a surface representing equal pheromone re-release fr om leaves around a central point source was defined by interpolation f rom a three-dimensional transect. Leaves harvested from 5 cm under the dispensers showed the highest pheromone release rate. Leaves downwind of the dispensers also had higher releases of pheromone. In a treated orchard, significantly higher EAG measurements were recorded in the r ows of trees that contained dispensers, compared to grass interrows or untreated trees. The implications of foliar pheromone adsorption and release on atmospheric concentrations and insect behavior require furt her investigation.