Oriental fruit moth phenology in North Carolina apples and ecdysone agonist activity on oriental fruit moth and codling moth

Oriental fruit moth, Grapholita molesta (Busck) and codling moth, Cydia pomonella (L.), are internal fruit pests of apple. Codling moth is recognized as a pest of apple, but until the last several years, oriental fruit moth was considered primarily a pest of peaches. Elimination or reduction of organophosphate insecticides and their replacement with reduced-risk insecticides has created the need to evaluate the activity and efficacy of these newly introduced insecticides. The purpose of this research was to evaluate the activity of the ecdysone agonists tebufenozide and methoxyfenozide for codling moth and oriental fiuit moth and to develop management strategies for early season control of the two pests. Methoxyfenozide had greater activity than tebufenozide on codling moth and oriental fruit moth eggs and was active for at least 28 d. Residue breakdown of the two ecdysone agonists was similar, with 60 and 80% decline at 14 and 28 d after application, respectively. Effects of sublethal exposure to methoxyfenozide on the population dynamics of oriental fiuit moth was studied in single tree cages and laboratory studies. Population differences were observed between treated and untreated field cages, but could not be directly attributed to sublethal effects of methoxyfenozide; no sublethal effects were observed in laboratory studies. The phenology of oriental fruit moth was studied using egg sampling and pheromone traps to increase the knowledge of the pest in apple. Oriental fruit moth eggs were found on cluster leaves early and on fruit late in the season, predominantly on the top leaf surface and calyx end of the fruit. A degree-day model for oriental fruit moth oviposition was developed and the start of second-generation oviposition was predicted to occur at 507 DD (7.2 C base temp) after peak trap catch. Spray timing of methoxyfenozide was varied for control of codling moth and oriental fruit moth; two applications applied at 21-d spray intervals provided high levels of control for both pests.