Development of a robust, multiple-species pheromone-based control strategy to support organic apple and pear production systems

Project code: PRR03-260

Project Lead

Gary Judd - Agriculture and Agri-Food Canada

Objective

To expand the efficacy of pheromone-based mating disruption tools by developing a multi-species control using a novel delivery system

Summary of Results

This research project proposed to expand the efficacy of pheromone-based mating disruption tools by developing a multi-species control using a novel delivery system. The research team had already demonstrated that codling moth and economically important leaf rollers can be controlled using a generic multi-component pheromone blend. The incorporation of this generic pheromone blend into a delivery system would allow it to be economically applied in commercial settings. To this end, research was undertaken to investigate the use of varied sprayable formulations which would allow incorporation with other management practices.

This project has provided proof-of-concept that monitoring larval codling moth (CM) with a newly-identified pheromone is feasible as a means of risk-rating pome fruit orchards before application of pheromone-based mating disruption as a control tactic. This trapping method also improves opportunities for control of CM using mating disruption by reducing overwintering populations prior to applying pheromones. This project resulted in the development of a new and improved lure for monitoring adult, codling moths. This new lure based on combining acetic acid (feeding attractant) and pear ester (host-plant kairomone) is by far the most attractive non-pheromone based lure yet developed for this pest. This lure is particularly attractive to mated, female codling moth, and is the most robust technology yet developed for monitoring adult codling moth in pheromone-treated orchards. When fully commercialized, producers will have the ability to selectively monitor the reproductive status of females (mated vs. non-mated) within an orchard to (a) determine the success of pheromone-based control tactics during the season, and (b) monitor potential immigration of already mated females into a pheromone-treated orchard; both of which undermine use of selective controls like pheromones. For the first time, producers will have the knowledge to intervene and apply supplemental controls as necessary before damage has occurred if mating disruption is failing for either reason. The project also provided proof-of concept that simultaneous disruption of multiple moth species is feasible with microencapsulated (MEC) pheromones. Laboratory and field trials demonstrated the 21-day efficacy of 3M-MEC-LR® against three-lined leafroller, Pandemis limitata, and oblique-banded leafroller, Choristoneura rosaceana, and 10-day activity of Suterra CM-FL against CM when mixed and applied simultaneously as a multiple-species pheromone-based control. This study demonstrated that inherent shortcomings of MEC pheromones, high initial pheromone release rate that quickly drops to low levels within several days, and microcapsules with poor retention on foliage under various environmental stresses such as rain and UV light, could be improved when MEC pheromones were formulated with horticultural oil, e.g. Purespray Green®. Oil formulation or tank mixing oil and pheromone improved release-rate characteristics of pheromone and retention of micro-capsules on leaves. Laboratory assays showed that the addition of 2% oil to MEC pheromone moderately increased communication disruption of both leafroller species but not codling moth. In small-plot field studies, MEC-oil formulations provided significant communication disruption for greater than 42 days, whereas MEC-water formulations were active for only 21-days. In addition, foliar residues of MEC + 2% oil significantly reduced female reproductive output, and topical oil applications to egg masses caused 99% egg mortality, whereas water-based MEC formulations had no such effect. At this application rate no phytotoxicity was seen on apple leaves. Results demonstrate the compatibility of formulating a MEC pheromone with horticultural oil, and suggest that this strategy could fit well into an integrated management programme against tortricid pests in apple agro-ecosystems. Implementation of results requires development of commercial release technology for the lures shown to be effective for codling moth larvae and adults. Lures need to be made available for national testing. Use of MEC pheromones and horticultural oils as pest control products for summer use against leafrollers and codling moth requires commercial companies willing to market these technologies in Canada before national tests.

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