The role of pheromones and larval behavior in the management of the tufted apple bud moth, Platynota idaeusalis (Lepidoptera: Tortricidae) in apples

The research investigated various aspects relative to the integrated management of the tufted apple bud moth, Platynota idaeusalis, including mating disruption, modeling of fruit injury by pheromone trap capture, and larval behavior. Mating disruption trials were conducted to test the efficacy of sprayable pheromone and microsprayers to manage populations. Fruit injury due to tufted apple bud moth ranged from 2.53% to 15.54% for sprayable pheromone treatments and from 2.66% to 8.65% for microsprayers over the three years of the study. The percent trap capture reduction ranged from 14 to 56 for the sprayable pheromone treatments and from 40 to 86 for the microsprayers. Trap catch and fruit injury indicated that the Phase II formulation was the most effective sprayable pheromone, but it was unclear which microsprayer formulation was more effective.; It was determined that mixing sprayable pheromones had the potential to lower the attractiveness of individual pheromones to their target species. Oriental fruit moth pheromone became significantly less attractive when tufted apple bud moth pheromone was added to it. All pheromones tested were most attractive when not mixed with the exception of Oriental fruit moth pheromone which became more attractive when mixed with codling moth pheromone. The fungicides captan, benomyl and ziram did not lower the attractiveness of tufted apple bud moth pheromone when mixed.; Models were constructed to predict egg mass deposition and fruit injury from early season trap capture. The best model to predict egg mass deposition used cumulative trap catch through 15 May as the independent variable and a square root transformation of the number of egg masses found per 5 min count as the dependent variable, calculated separately for each brood. To predict fruit injury, the best model used cumulative trap capture through 16 June to predict total harvest injury due to the tufted apple bud moth. The model was “percent harvest injury” = 0.14 + 0.046CumulativeCatch16June,” r2 = 0.24, p = 0.006.; Observations determined that tufted apple bud moth larvae construct leaf shelters through a series of behaviors: sustained walking, casting in the air, silking, and cutting the leaf petiole, but the percent of time engaged in particular behaviors varied among instars. Larvae released onto fruit began silking behavior significantly sooner than larvae released onto foliage. Observations also revealed that larvae can create more than one leaf shelter during development and that larvae feed extensively outside of leaf shelters on green tissue. Once a leaf shelter is constructed, the probability of remaining in the tree and containing a live larva decreases from 68% in the week after it is created to 23% two weeks later and to 0% in the following week. At the same time the probability of the shelter falling from the tree rose from 5% in the first week to 63% in the sixth week.