WERA043: Developing Sustainable and Organic Pest Management Programs for Western Orchard Systems
Statement of Issues and JustificationApple and pear are grown on 300,000 acres in five states (WA, OR, ID, UT, CA) and the region accounts for 70% of the fresh market apples sold in the US and 90% of the total pear production. In addition, walnuts are produced on nearly 200,000 acres in CA. Organophosphate (OP) insecticides have historically been the most widely used class of insecticides in pome fruit orchards in the western US. Most of these insecticides have been targeted at control of Codling moth (CM), Cydia pomonella L., and leafroller species (Beers and Brunner 1991, NASS 1992, NASS 1994, NASS 1996, NASS 1998, NASS 2000, NASS 2002, NASS 2004, NASS 2006), both key pests of western pome fruit production (Beers et al. 1993). Resistance to OP insecticides has been documented in the key pests of pome fruit, codling moth and leafrollers, throughout the western US (Varela et al. 1993, Knight et al. 1994) as well as in other fruit producing regions (Reissig et al. 1986, Lawson et al. 1997, Waldstein et al. 1999, Ahmad et al. 2002). Many secondary pests, such as aphids, leafhoppers, and leafminers, have also developed high levels of resistance to OP and carbamate insecticides.
The impact of the Food Quality Protection Act of 1996 (FQPA) has been to cancel registrations of or limit the availability of OP insecticides in many crops, including tree fruits and nuts, because apple and pear are important foods in the diets of infants and children (NAS 1993). While the Environmental Protection Agency (EPA) has continued regulatory actions continue against older insecticides they have registered several new insecticides and miticides classified as reduced risk and/or OP replacements for use on pome fruits. These new insecticides generally offer much greater safety margins for humans and the environment compared to products they replace. There is concern and some evidence (Dunley et al. 2006) that resistance development in key pests will develop in a few years if the newly registered insecticides are not managed appropriately. The availability of new pest control tools in several different chemical classes (IRAC 2007) provides an opportunity to develop sound resistance management strategies to conserve new products. However, having more chemical control choices also makes management decisions more complex, especially when differences of timing, stage specificity, and increased demands of operational factors (spray coverage) of the new products are considered.
The widespread adoption of CM mating disruption (CMMD) in western apple and pear orchards resulted from efforts of the Codling Moth Areawide Management Project (CAMP) - 1995-1999 (Calkins 1998, Brunner et al. 2001). The same group of scientists involved in CAMP conducted two additional projects, IFAFS (Building a multi-tactic pheromone-based pest management system in western orchards) and RAMP (Enhancing pheromone mating disruption for lepidopteran pests in western orchards), which helped stabilize and extend the benefits of CAMP through research and educational activities. Results of the latter two grants expanded the use of CMMD in apple and pear (c.a. 70% of acres in WA by 2005) and helped establish a foundation for adopting new chemical control technologies in apple and pear pest management programs.
The traditional mechanisms of delivering pheromone to orchards for purposes of pest control have been to hand apply dispensers at densities of 200-400 per acre. New delivery systems have been developed in attempts to improve the efficacy of pheromone treatments and automate delivery or reduce costs. These new systems include microencapsulated formulations (Knight and Larsen, 2004, Il'Ichev et al. 2006, Stelinski et al. 2007b), flake of fiber technologies (Doane 1999), wax-based formulations (DeLame et al. 2007, Stelinski et al. 2007c), meso-dispensers (Doane 1999), and puffers or misters (Isaacs et al. 1999, Knight 2004, Stelinski et al. 2007a). Results with these alternative pheromone delivery systems have been variable across pest species (Gut et al. 2004) but the research activity in this area has brought some challenges to the classical thoughts on mechanisms of pheromones when used as controls for agricultural pests (Miller et al. 2006a,b). In addition, the discovery that the CM was able to detect and respond to a kairomone, pear ester, (Light and Knight 2005, Knight et al. 2005, Knight and Light 2005, Michell et al. 2008) has opened up new areas of research on this and similar kinds of chemistries for use as monitoring devices or as controls.
A major impact of the IFAFS and RAMP grants was insights on the effect of reduced risk and OP replacement insecticides on certain biological control agents. These newly registered insecticides were initially considered of lower risk to biological control agents but studies have demonstrated sublethal impacts that have resulted in disruption of important natural control systems relied upon for years.
The proposed new coordinating committee broadens the focus of the previous committee. The new coordinating committee will provide a vehicle to continue and enhance the coordination of research projects and exchange of ideas and information that exist within the region and to expand the focus to crops other than pome fruits. It will coordinate activities and possibly hold joint meetings, with committee participants from the eastern US working on similar kinds of issues associated with deciduous tree fruits.
The proposed coordinating committee will address issues of transitioning IPM programs to reduced risk or OP replacement insecticides, development of new methods of pheromone delivery for mating disruption, development and evaluation of kairomone-based or pheromone-kairomone monitoring methods, determination of the impact of reduced risk or OP replacement insecticides on natural enemies, evaluation of how modification of orchard habitats and nearby natural habitats can enhance biological control, and information transfer to pest management decision makers. All of these issues are of critical importance to the western orchard industry. New knowledge generated from these activities will provide greater stability of "soft" pest control programs allowing growers and crop consultants to implement multi-tactic programs with a greater degree of confidence. The transition to reduced risk or OP replacement insecticides will reduce risk of negative environmental impacts of pest management practices, a benefit to all citizens living in the western region. However, the group most directly benefiting from this transition will be farm workers.
Stakeholders (fruit growers, packer-shippers, farm workers) consistently identify insect injury to the crop or products used to control them as being among their top priorities. In the western US the codling moth, leafrollers, pear psylla and western cherry fruit fly are annually among the highest priority for research funding by commodity commissions. Market access is more and more being determined by pesticide residue issues as much as fruit quality. Insecticides, especially the older broad-spectrum products, are those marketers are scrutinizing on fruits and vegetables. The western US exports a significant portion (30-35%) of tree fruit crops each year. The threat of closure of foreign markets due to contamination of export shipments by pests is an increasing concern to the tree fruit industry. For example, the apple industry estimated that closure of the Taiwan apple market in 2004 cost the industry $25 million in lost revenue due to the discovery of codling moth larvae in three fruit shipments.
The group of scientists who have and will again participate in the WERA-43 coordinating committee represents a group that has been collaborating for several years and represent individuals from CA, OR, UT, and WA. This group has successfully written and acquired competitive federal grants based on ideas and synergy arising from past WERA-43 meetings. The CAMP, IFAFS, and RAMP projects are excellent examples but not the only ones. In addition, many research and extension personnel from the mid-west and east coast who work in tree fruit crops regularly attend WERA-43 meetings and contribute to discussion and also are collaborators on research projects. The research objectives and procedures in this proposal are in most cases on-going activities that the WERA-43 participants are already involved with. Therefore the technical feasibility of proposed research activity is well established.
The negative impact on biological control agents of newer insecticides through sub-lethal effects represents a challenge to the future of "soft" pest control programs in orchard systems. This information has, however, allowed scientists to realistically classify new insecticides and their effects on biological control agents and this will help growers make better selections of products and how to use them in their pest management programs.
A large cooperative project, the genesis of which was a previous WERA-043 meeting, has contributed much to the discussion on understanding mechanisms of pheromone mating disruption and how to stabilize programs using this technology. This project developed baseline data on behavior and electro-physiology of codling moth that will be used to address future questions of resistance development to pheromones. Additional advances in pheromone mediated pest control would be expected as a natural part of the new project. Research into alternative methods of delivering pheromones will lead to products that are less expensive and more effective than current products. This will result in lower costs to growers, increased use of pheromone technologies as well as increased use of safer pesticides.
The promise that kairomones may be useful to enhance pheromone mating disruption is being more carefully evaluated and critical questions have arisen out of past meeting discussions. The interactions at the 2007 WERA-043 meeting stimulated interest and intentions by several researchers to pursue further this avenue of investigation. Additional advances on the use of kairomones and associated technologies could enhance pheromone mating disruption of provide better monitoring tools to help stabilize pheromone-based systems.
The threat of resistance development to newly registered insecticides has raised interest in scientists contributing more of their resources to this area and will likely result in formation of collaborative working groups in this area. Concerns over resistance from the WERA-043 group will help shape pest management recommendations toward sound resistance management strategies for growers.
Phenology models for codling moth are being re-examined in light of biological data indicating a shift in pest life histories over time. A group within WERA-043 is looking at ways to make model output easier to use as tools in pest management through the development of a Decision Aids System (DAS) (http://entomology.tfrec.wsu.edu/das/). This latter system integrates weather data, model output, pest management recommendations and negative effects of pesticides on natural enemies in real time via the web. Systems like DAS can be shared across regions to make real-time on-line pest management decisions available to more in the fruit industry.
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