Sprayable Microencapsulated Sex Pheromone Formulations for Mating Disruption of Four Tortricid Species: Effects of Application Height, Rate, Frequency, and Sticker Adjuvant

Several application parameters of microencapsulated (MEC) sex pheromone formu- lations were manipulated to determine their impact on efÞcacy of disruption for codling moth, Cydia pomonella (L.); oriental fruit moth, Grapholita molesta (Busck); obliquebanded leafroller, Choristo- neura rosaceana (Harris); and redbanded leafroller, Argyrotaenia velutinana (Walker). Depending on the experiment, the formulations evaluated were those formerly manufactured by 3M Canada (Lon- don, ON, Canada) or those that are currently available from Suterra LLC (Bend, OR). The efÞcacy of MEC formulations applied by air-blast sprayer evenly throughout the entire canopy of 2Ð3-m-tall apple (Malus spp.) trees was equivalent to treatments in which targeted applications of MECs were made to the lower or upper 1.5 m of the canopy (at equivalent overall rates) for oriental fruit moth and both leafroller species. The realized distribution of deposited microcapsules within the tree canopy corresponded well with the intended heights of application within the canopy. The additional coapplication of the pine resin sticker Nu-Film 17 increased efÞcacy but not longevity of MEC formulations for oriental fruit moth; this adjuvant had no added effects for codling moth or leafroller formulations. Increasing the rate of active ingredient (AI) per hectare by 20 Ð30-fold (range 2.5Ð75.0 g/ha) did not improve the disruption efÞcacy of MECs for codling moth or either leafroller species when both low and high rates were applied at equivalent frequencies per season. A low-rate, high-frequency (nine applications per season) application protocol was compared with a standard protocol in which two to three applications were made per season, once before each moth generation for each species. The low-rate, high-frequency protocol resulted in equivalent or better disruption efÞcacy for each moth species, despite using two-fold less total AI per hectare per season with the former treatment. The low-rate, frequent-application protocol should make the use of MEC formu- lations of synthetic pheromone more economical and perhaps more effective.