Brief Summary of Minutes of Annual Meeting

The agenda was divided into major categories of discussion topics: pesticide resistance in key tree fruit pests; insect behavior and biology; pheromone delivery technology and assessment; new pests; biological control issues and options; organic research and biological pesticides; next meeting timing, location and topics. Discussion focused on short reports of current activities and concepts or issues that are shared by different researchers. The intent of the meeting format was to bring out discussions of common problems, approaches to researchable issues (methods discussion), and new problems that offer new opportunities for research. The following summary is organized by agenda topic and captures the essence of discussions that occurred. Pesticide resistance in key fruit pests. Codling moth (CM) resistance to organophosphate (OP) insecticides has been noted in all western states and in most eastern states. Levels of resistance are variable and do not usually confer complete field failures in orchards relying primarily on these products for CM control. CM was adequately controlled with several insecticides, including an OP, in one orchard showing signs of OP resistance (moderate levels) in 2003. One report indicated that OP resistant CM populations had a different phenology, delayed development, than populations that were not resistant. A survey of obliquebanded leafroller (OBLR) tolerance to several insecticides showed that resistance to OP insecticides remained high and that cross-resistance between OPs and an insect growth regulator was present in every population tested (8). For the first time a shift in tolerance was detected in OBLR to spinosad, a relatively new insecticide in use for only 5 years. Every population tested showed an increase in tolerance of from 3 to 11-times relative to a susceptible colony. Some evidence of OBLR resistance to an insecticide not yet registered in tree fruit raised concerns about cross-resistance between OP insecticides and new chemistries. Insect behavior and biology. CM phenology was discussed in detail. In many situations the degree day model that has been used for many years to predict CM development and to time control activities was not providing accurate representations of the pests biology. Several possible reasons were considered but a general consensus was that we simply had not addressed this issue with good research. Some possible research approaches were discussed and experimental procedures were debated. No consensus was reached in the meeting about what teams might be formed to address this issue. OBLR was found to have a 4 to 5 fold higher reproductive output than CM. Delay of mating in OBLR and CM were shown to have a significant impact on both insects reproductive output. The age of either the male or female has an affect on reproductive output. A delay of 4 days in mating can result in a 60-70% reduction in egg production. Longer delays almost completely eliminate production of viable eggs. This information helps explain why we capture mated females in pheromone treated orchards but we do not necessarily observe significant crop losses. Vertical wind tunnels were used to examine the effects of CM or OBLR density on mating. For CM, in the absence of pheromone, having multiple males present in the tunnel did not increase the percentage of calling females that mated, but did decrease the time required to mate. When pheromone sources were added (lures with 0.01x, 1 or 10x load rates) mating decreased dramatically and tended to occur primarily in the situations with multiple males present. For OBLR, the peak mating in non-mating disruption conditions occurred with two males. When mating disruption conditions were being simulated, except in the lowest dose, mating only occurred in the situations with 2 or 3 males present. Adding more OBLR males decreased the time required to mate under both mating disruption and non-mating disruption conditions. When CM female equivalent dispensers (flakes) were placed around a virgin female there was a direct relationship between dispenser density and male attraction. There was some discussion about CM behavior and how pheromone sources interact with mate location and this discussion was continued in the next section. New information on phenology models for OBLR and another leafroller species, Pandemis pyrusana, were presented. This information adjusts thresholds for OBLR and provides instar specific development for both species. Vince Jones presented a new method of marking field populations of insects with proteins. The method is being used to assess movement of moths, leafroller parasites and general predators of pear psylla. The technique appears to provide a powerful method to enhance our understanding of movement of natural populations of pests and their natural enemies. Pheromone delivery technology and assessment. There were several reports on different kinds of new technology for delivering pheromone for control of CM and OBLR. A new method of delivering a microencapsulated pheromone formulation showed promise in control of CM. A fiber pheromone formulation showed promise for managing CM populations in low to moderate pressure orchards when supplemented with insecticides, however, aerial applications of this technology met with some difficulties. A new flake type pheromone delivery technology was evaluated for longevity and retention in trees. This technology is adapted from that used in the gypsy moth control program. A wax-based pheromone formulation being developed by MSU was evaluated in small plots to determine the effect of wax droplet densities on the mating of Oriental fruit moth (OFM). Results showed an increased orientation disruption to tethered virgin female moths as the density of pheromone emitting wax droplets increased. The hypothesis was that this provided evidence for competitive attraction as the mechanism, but some debate about this conclusion resulted. A method of assessing pheromone release from hand-applied dispensers was presented and its value in assessing release of pheromone from different kinds of formulations was discussed. A detailed discussion on mechanisms of mating disruption took place. Some interest in members of the group to form a working group around this topic has resulted in new research projects being submitted to commodity commissions, private groups and other agencies. There was considerable discussion about monitoring CM in pheromone treated orchards. A non-pheromone attractant that has been evaluated for several years was shown by some researchers to have value as a monitoring tool while other researchers indicated difficulty in repeating research results or to understand how the attractant worked. Some new research on other non-pheromone attractants for CM, especially b-farnesene, was discussed. The area of non-pheromone attractants for CM was identified as an area of interest. Biological control issues and options. The effort to enhance biological control of leafrollers by habitat manipulation was discussed by Tom Unruh. Wild rose gardens established at different orchard locations and seeded with the strawberry leafroller and a key leafroller parasite, Colpoclypeus florus, have shown promising results at some locations but challenges at others. At some locations growers have over sprayed gardens and thus eliminated the alternate host for C. florus, the strawberry leafroller. In some locations natural reduction of strawberry leafroller densities have occurred but the reasons for this are not apparent. Vince Jones discussed the phenology of leafrollers and biological control agents, parasites, and how different degree-day intervals can be used in sampling to assess the presence and impact of these agents. Peter Shearer discussed the effects of several insecticides in natural enemies in peach orchards, especially effects on Chrysopa sp. New pests. An update on the stink bug, Halyomorpha halys (Heteroptera: Pentatomidae), was provided by Peter Shearer. This insect was first detected in Allentown, PA in 1996 but not correctly identified until 1999. It has its origin from eastern Asia. It is unclear how it entered the US. It has a wide host range and feeds on numerous horticultural and agronomic crops including apples, peaches, pears, grapes, vegetables, ornamentals, and soybean. It also is considered as a nuisance pest when it overwinters in large numbers inside homes. Shearer presented some of his ongoing research including pheromone trapping and laboratory efficacy studies. Organic research and biological pesticides. John Dunley reviewed progress on the areawide organic pear project in Washington. In the third year organic or very soft products easily managed the densities of CM and pear psylla. The cost of organic pest control was the same or is less than conventional practices. Growers in the project have formed a marketing group and are getting higher ($2/box) prices for their product, due mainly to assurances of zero pesticide residues. Several researchers reported on experience with different CM granulosis virus formulations. Lerry Lacey talked about the stability of different formulations. The main virus used in orchards is Cyd-X and it was used on almost every acre of organic production in WA and OR in 2004. There was a good deal of discussion on how to implement the CM virus in conventional CM control programs as a long-term strategy to suppress populations and create a more favorable situation for mating disruption. Results of studies with the organic formulation of spinosad, Entrust, showed that it was as effective against leafrollers and CM as the conventional formulation, Success. Entrust used in conjunction with CM virus and mating disruption have been used to bring serious CM problems in organic orchards under control in one generation at two different locations. These examples demonstrate the power of combining multiple tactics against a key pest to bring populations to the point where maintenance can be achieved by mating disruption and virus only. Entomopathogenic nematodes were shown to be a viable tool for control of the overwintering stage of CM. High rates were needed to achieve high levels of control but lower rates might provide enough control along with other soft tactics to provide maintenance of CM at acceptable densities. The combination of different in-row mulches used for weed control and water management was demonstrated to also be beneficial to nematodes. Research on insecticide-baits was conducted for control of apple maggot and blueberry maggot. The baits sprays reduced infestation in both fruit relative to an untreated control. Behavioral observations showed that the flies were not strongly attracted to the baits but became arrested and searched more on foliage with droplets. Research into enhancing the attactancy of baits is being conducted in MI and WA. Next meeting location, time and topics. There was considerable discussion about the proliferation of meetings that researchers are asked to participate in. The traditional timing of the WCC043 meeting had been late October. This is getting to be a more and more difficult time of year for people to meet and it coincides with industry meetings of eastern researchers. The participation of eastern research and extension personnel in the WCC043 meeting is valued because of the depth and scope it brings to the discussions. It was decided to hold the next meeting just prior to the Western Orchard Pest and Disease Management Conference (WOPDMC) in 2006. This meeting is held annually in January in Portland, OR at the Hilton Hotel. Since many researchers and extension personnel who attend the WCC043 meeting also participate in the WOPDMC the combining of two meetings was considered an efficient use of everyones time and resources. The meeting WCC043 meeting will be held on Tuesday and half of Wednesday of the week the WOPDMC is held each year. An organizing committee headed by Peter Landolt was appointed to establish a meeting theme for 2006. The intent of the group was to focus on specific issues of importance and to conduct a meeting around problems, concepts, experimental designs, and cooperative projects.

The most important accomplishment of this year's meeting was the exchange of information on results of different studies involving methods for managing pests in orchard ecosystems. The sharing of information on use of different pheromone technologies has resulted in the formation of a team of researchers that are proposing significant changes in research direction to challenge current assumptions on how this technology works against CM. This may be one of the most important accomplishments of the meeting. Growers have a high interest in use of pheromones for CM control but are concerned that it does not always work as well as it should, pointing to a lack of understanding either how the technology works or of the limits under which it should be expect to work. In either case a better understanding of CM behavior and effects of pheromones and other plant volatiles on mating success is needed. Much of the research on alternatives to OP insecticides discussed at the meeting is being shared with growers and crop consultants. There is a great need, especially in WA, to help the fruit industry understand how to use OP alternatives more effectively due to regulatory demands on cholinesterase testing and worker re-entry intervals. A presentation at the Washington Horticulture Association meeting will focus on alternatives to OP insecticides and several presentations will be given at industry meeting throughout the winter (2004-05). A manual on producing apples without use of OP insecticides is under development and a web-based version should be available prior to the 2005 growing season. Reducing dependence on OP and other broad-spectrum insecticides can be accomplished by continued research on CM viruses, Entrust, and entomopathogenic nematodes. These products and organisms have the potential to provide enough additional mortality of CM to allow for more stable, effective, and less costly soft or organic programs. The introduction of the CM virus into the conventional apple and pear pest control programs will initiated and followed to determine its value in reducing CM densities over several generations. Biological control has always been a component of IPM programs in the western US. Integrated mite control was one of the first and has been the most stable biological control programs in agriculture. Growers know that biological controls can help them combat pests but must fit into the demands for high quality fruit and low pest damage. The effort to establish or manipulate selected native habitats near orchards for the express purpose of providing refugia for natural enemies is new to the orchard industry. By combining use of pesticides that do not negatively affect natural enemies and habitat that conserves natural enemies, biological control of even direct fruit pests like leafrollers is possible. Growers are very interested in projects where habitat manipulation can be incorporated into their normal practices, if it can be shown to have benefit.

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