1a. Objectives (from AD-416)
Pear ester has been identified as both a larval and adult attractant for codling moth. Management strategies utilizing pear ester are being developed along several avenues. Both basic and field studies are needed to optimize the rates of pear ester and blends with sex pheromone to achieve effective levels of control. 1. Characterize the emission rate of pear ester over time from field-aged microencapsulated formulations (MEC). 2. Examine larval behavior on host plants treated with various rates and deposition patterns of pear ester MEC. 3. Evaluate the effectiveness of adding pear ester to various insecticides to increase larval mortality including the role of crop and cultivar on activity. 4. Evaluate the interactions of pear ester and sex pheromone combined in various blend ratios on moth orientation responses. 5. Examine the effect of pre-exposure to various rates and blends of pear ester and sex pheromone. 6. Evaluate the effectiveness of various dispensers loaded with blends of pear ester and sex pheromone on male captures by virgin female-baited traps.
1b. Approach (from AD-416)
1) Volatile recapture methodology will be used to quantify the emission rate of pear ester from the MEC formulation aged on apple foliage over a 35 d period. 2) Larval observations will be conducted using several cultivars of apple, pear, and walnut foliage treated with the MEC formulation. 3) Field bioassays will be conducted with a select group of new insecticides registered for codling moth to examine whether the pear ester MEC can enhance insecticidal activity. These studies will focus on the apple cultivar Granny Smith. 4) A piezoelectric sprayer will be used to examine the subtle interactions of pear ester and sex pheromone on adult orientation behaviors. 5) Moth antennal responses following pre-exposure to sex pheromone and pear ester blends will be examined using an EAG and flight tunnel tests will examine moth orientation behavior following exposure. 6) Dispensers loaded with various blends of sex pheromone and pear ester will be evaluated in replicated field plots using virgin female-baited sticky traps.
3. Progress Report
This project is an extension of research on the management of insect pests of temperate tree fruits and addresses objective 3 of the related in-house project. This project relates to NP 304 2B, Protection of Agricultural and Horticultural Crops Control, because it aims to improve control of codling moths that damage apple and pear by integrating natural attractants with pesticidees and using natural attractants to determine when control is needed. Research is being conducted to utilize the behavioral activity of pear ester for both larval and adult codling moth to improve grower’s ability to manage this pest with reduced levels of insecticides. There are three primary objectives in this project. First is to improve the performance of supplemental insecticide sprays by tank-mixing a microencapsulated pear ester formulation with insecticides to enhance larval wandering and increase larval exposure to toxic residues before they attack the fruit. Second is the addition of pear ester to sex pheromone either in dispensers or as a spray of microencapsulated formulation of pear ester to enhance the disruption of male and female moth communication and thus reduce mating and subsequent egg laying. Third is to use pear ester in combination with sex pheromone and a food lure to improve monitoring of both sexes. Studies accomplished each of the objectives. Replicated plots were treated with experimental hand-applied dispensers loaded with combinations of sex pheromone and pear ester or sex pheromone alone. Sub-plots there then treated with the use of either insecticides alone or insecticides plus the microencapsulated pear ester. Significantly fewer wild mated female moths were captured on interception traps and fewer virgin female-baited traps caught males in plots treated with sex pheromone and pear ester versus sex pheromone alone. In addition, levels of fruit injury were lower in the sex pheromone plus pear ester-treated plots. The addition of an acetic acid co-lure to traps baited with the pear ester plus sex pheromone lure were more attractive and female catch was 7-fold higher. In addition, within plots treated with pear ester plus sex pheromone dispensers the use of the acetic acid co-lure increased levels of female moth catch 15-fold. The significantly greater catch of female codling moth aids the development of a precision management approach where growers can reduce their total use of insecticides by targeting sprays to only portions of orchards where moth catch exceeds a threshold. This approach was implemented with two growers on 300 acres and reduced growers’ management expenses for codling moth by 60%. Monitoring of activities and progress in this report was accomplished by direct supervision of on-site employees, and use of site visits, email and telephone to communicate with off-site collaborators.