Influence of Weather and Time of Day on Plum Curculio (Coleoptera: Curculionidae) Tree Canopy Entry Behaviors and Evaluation of Traps for Predicting Fruit Injury

In the spring of 1997, tree canopy entry behaviors of adult plum curculios, Conotrachelus nenuphar (Herbst), were estimated by three types of traps examined five times each day from 24 May (bloom) until 15 June in an unmanaged apple orchard. In addition, presence of plum curculios in the canopy, ovipositional injury to fruit, and local weather conditions (temperature, barometric pressure, relative humidity, and wind speed) were monitored. The principal means of entry into apple trees by plum curculios appeared to be direct flights from outside the canopy into the canopy. However, the major means of tree entry on days when large amounts of oviposition occurred appeared to be crawling up or flying onto the trunk. Ovipositional injury to fruit was correlated with high temperature and low barometric pressure. The greatest amount of tree entry occurred between 1800 and 2100h. The strongest correlation found between daily trap captures and daily occurrence of injury was between captures by flight interception traps placed just outside the canopy and injury occurring the following day. Based on this, captures by flight interception traps just outside the canopies of fruit trees may have potential for predicting episodes of plum curculio damage to fruit.