Modeling the phenology and monitoring the activity of the plum curculio Conotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae) with novel methods and technology

Increasing legal restrictions on chemical pesticide use in stone and pome fruit orchards have stimulated research into developing better management and monitoring tools for the northern strain of the plum curculio, Conotrachelus nenuphar (Herbst).;Plum curculio larvae may be targeted with management tactics as they emerge from fruit, so existing models for larval emergence from fruit were evaluated for accuracy while examining the effect of multiple larvae and fruit type upon emergence timing. Larval emergence timing, quantified as degree days (base 11.1°C), was recorded in tart cherries on trees, and emergence timing was recorded in multiple apple varieties both in cyclical field conditions and in constant laboratory conditions. Adult emergence from pupation in soil was recorded in the laboratory and compared with existing model predictions. Model predictions did not always accurately reflect the timing of larval or adult emergence. Colder conditions and changing host fruit type had no significant effect on larval emergence timing but changing host fruit type correlated with a shorter pupation interval. Results suggested that females preferred to oviposit on multiple fruit rather than lay multiple eggs in one fruit. More larvae per fruit resulted in a significantly longer emergence period in apples.;Incorporating camera systems into insect traps potentially benefits not only plum curculio monitoring, but insect phenology modeling, non-lethal insect monitoring, and research into the automated identification of traps counts. Cameras originally for monitoring mammals were adapted to monitor the entrance to pyramid traps designed to capture adult plum curculios. With field tests, two new trap designs (v.I and v.II) traps were evaluated on the basis of battery power, ease-of-maintenance, adaptability, required-user-skills, cost (including labor), and accuracy-of-results. The v.II design surpassed five of the six criteria used to evaluate success. Significantly more adults entered the camera traps between six in the evening and midnight. When compared with conventional pyramid traps, the v.I traps collected a similar number of adults. Two observed but not significant trends were that the v.I traps collected twice as many adults as the v.II traps while at the same time the v.II traps collected more than twice as many photos per adult as the v.I traps.;The responses of adult plum curculios to contrasts in color and illuminance were assessed in field and laboratory conditions. Results from four field sites showed that significantly more adults exhibited positive taxis towards traps with woods behind than to traps in an open field. Laboratory tests showed that significantly more females and males exhibited positive taxis towards areas of black. The color black correlated with lower reflected illuminance (<110 lux), and when environmental lux was reduced to ten or less, the significant adult positive taxis towards black was not evident. The combined results suggest that adults will move towards the largest areas of low illuminance in the environment. Low illuminance should be the standard for future plum curculio traps, and applications of materials reflecting illuminance to an orchard could be explored as a means to manipulate adult behavior.