Use of traps for monitoring adult leafrollers in apple orchards

Abstract

Port wine bait traps placed in Canterbury apple orchards caught leafrollers, trapping more female than male moths (with the extent of this difference varying with species). Most of the trapped females had mated, as shown by the presence of spermatophores in their bursa copulatrix. Mating frequency was related to moth population density and species. At lower population densities, mating was reduced. Greenheaded leafroller (Planotortrix excessana (Walker)) females mated more frequently than either brownheaded leafroller (Ctenopseustis obliquana (Walker)) or lightbrown apple moth (Epiphyas postvittana (Walker)) (LBAM) females. By comparison, an increase in pheromone trap catches of LBAM coincided with the beginning of oviposition by each flight. Bait trap catches were low during the second flight in January and February, whereas pheromone trap catches of the third LBAM flight were reduced (possibly by competition from the greater numbers of female moths present). A significant relationship between the numbers of LBAM caught by bait and pheromone traps inside orchards was found only when additional traps were placed along orchard borders.

Keywords:

• leafrollers
• moths
• traps
• pheromone
• bait
• apple orchards
• mating