Apple Production Without the Input of Neuroactive Insecticides

Apple Production Without the Input of Neuroactive Insecticides

Summary

Objectives

1. Determine the densities of arthropod pests and associated natural enemies and the level of crop loss due to arthropods in apple orchards using control tactics that do not include the use of neuroactive insecticides.
2. Determine the impact of augmentative and/or inoculative releases of selected parasites on the control of codling moth and leafrollers and their compatibility with non-neuroactive insecticides used for pest control.
3. Determine the economics of producing fruit without neuroactive insecticides and the potential for specialty markets or any value added to apples produced in this way.
4. Compare the level of neuroactive insecticides on fruit and in the soil in orchards using these products and those in the project not using them.
5. Determine the changes in soil fauna composition through time in orchards using neuroactive insecticides and those not using them.
6. Demonstrate and educate members of the apple industry via field days, popular journal or trade journal articles and presentations at grower meetings on the advantages and disadvantages of producing apples without the input of neuroactive insecticides.

Abstract

This project anticipated a new era of pest management in agriculture. The concept of the project was developed prior to the passage of the Food Quality Protection Act of 1996 (FQPA). Regulatory implementation of FQPA has and will continue to alter drastically the way pest management is implemented by banning or severely restricting use of certain pesticides in apple production. The project demonstrated that it is possible to produce apples without the input of broad-spectrum insecticides, that is, those that act on mammalian and insect nervous systems. However, whether this approach is practical and economical depends upon the pace at which novel pest control chemicals are registered, the appearance of new pests, and the discovery of new soft insecticide pest control tools.

This final report summarizes results collected over three years, 1995-1997. At six orchards, five in Washington and one in Oregon, insect and mite control using “soft” (non-neuroactive) insecticides was compared with conventional pest control programs. Control of key pests, codling moth and leafrollers, was maintained at acceptable levels without intervention of broad-spectrum insecticides at most locations. The use of mating disruption (pheromones) was a key to the control of codling moth in the soft insect management program. Supplementing mating disruption with soft insecticides was necessary at four locations in almost every year. In the initial year (1995), horticultural mineral oil was used to supplement codling moth mating disruption at four locations. At two locations mating disruption plus oil was not sufficient to prevent significant crop loss, greater than 4 percent. Confirm® (tebufenozide, Rohm and Haas Corp.), a new insect growth regulator, was used as a supplement to mating disruption in 1996 and 1997 and greatly reduced crop losses from codling moth and also helped to suppress leafroller populations.

In 1995 leafroller injury to fruit at harvest exceeded one percent in four of six sites using the soft insect management program. Use of Bacillus thuringiensis (Bt) products was not sufficient to keep leafroller densities from increasing at these locations. In 1996 and 1997 the use of Confirm suppressed leafroller densities and injury to acceptable levels in all sites using the soft insect management program. Conventional pest control programs were successful in preventing significant fruit injury in 1995 in five of six sites and at all sites in 1996 and 1997.

Other arthropod pests were generally at low levels in orchards using the soft insect management program. Natural enemies contributed to the suppression of mites, aphids and western tentiform leafminer in each year. However, the white apple leafhopper, green apple aphid and western tentiform leafminer, reached population densities that required intervention with insecticides in one or two of the orchards using conventional pest control programs.

Changes in arthropod community biodiversity were measured by taking samples in the orchard ground cover and soil. Results of pit fall trapping revealed some consistent differences in biodiversity between soft insect management program and the conventional program. Of greatest interest was the significantly higher numbers of carabid beetles in the former orchards. These data appear to support the hypothesis that highly mobile insects, especially general predators, were more at risk in the conventionally managed orchards, probably because they were exposed to higher levels of insecticide residue.

Project findings are being shared through conferences, workshops, field days, trade journal articles, and presentations at grower meetings. A presentation on the results of the project appears on the WSU-TFREC web site and may be accessed at the following address: http://entomology.tfrec.wsu.edu/jfbhome/reports.html.

Potential Benefits

The research project will definitely have an impact on the adoption of new and highly selective new technologies for pest management in Washington apple orchards. The project has demonstrated that products like tebufenozide and Bt products have a place, even in today’s production systems, and tomorrow’s systems are going to be more restrictive as regulations limit the use of most traditional pesticides in apple and pear production. Within five years, 2004, NNAI-type pest management systems using products like tebufenozide will be the norm instead of the exception in Washington apple production.

Sampling methods used in the SARE project have become fruit industry standards for assessing certain pest densities in other applied implementation projects such as the Codling Moth Areawide Management Project (CAMP), the Yakima Valley Pear IPM Project, and Wenatchee Valley Pear IPM Project.

The SARE project challenged the traditional fruit chemical thinning programs because no carbaryl (Sevin), a carbamate insecticide, could be used in the non-neuroactive insecticide (NNAI) plots, even though the intent of these treatments would have been for horticultural, not insect, management. Alternative chemical fruit thinning products new to the marketplace were used and somewhat successfully to reduce costs of hand labor for thinning excessive fruit from trees. One result of FQPA will likely be the loss of or restriction on use of carbaryl as a chemical in apple production.

Farmer Adoption

Many producers have adopted certain aspects of the technology introduced by this project. The primary technological adoption has been mating disruption for codling moth control and use of Bacillus thuringiensis (Bt) products for leafroller control.

Reactions from Farmers and Ranchers

The initial reaction from fruit growers and crop consultants to the proposed project, Apple Production without the Input of Neuroactive Insecticides, was that it would not work. Skepticism came from a lack of confidence in newer technologies and uncertainty about their reliability over time. The relative success of the project has helped change practices and minds concerning mating disruption, use of Bt products, and new insecticide technology like Confirm.
Implementation of the FQPA has resulted in a large increase in the adoption of mating disruption for codling moth control.

Future Recommendations

This project was extremely ambitious, especially based on the complexity of the apple production system and high value of the crop. A key to getting cooperator involvement in the initial year was the involvement of the Washington Tree Fruit Research Commission and, more importantly, their willingness to partner by putting up crop loss insurance. Though the insurance was never paid out, it gave the cooperators comfort that if insect control completely broke down in the NNAI orchards there would be some compensation. In projects where high risk technology is being implemented it would be valuable to have a crop loss insurance component associated with the project. How this is accomplished will differ depending on the project and the partners.

The impact of FQPA on tree fruit pest management will be more dramatic than on many other crops because apple, pear and peach represent such a large portion of infant and children diet. The SARE project has demonstrated that certain components of the conventional program could be changed with minimal effect on the production system.

This summary was prepared by the project coordinator for the 2000 reporting cycle.

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