|This was the second year in a three-year development project of an areawide organic pest management program for pears. In 2002 our lab began monitoring pest and predator densities in the the Peshastin Creek Areawide Organic Project. In 2003, we continued our pursuit of the two main objectives:
- Development of organic or soft pest management practices in an areawide context
- Comparison of pest densities, natural enemy densities, crop damage and cost effectiveness between pest management strategies categorized as:
- Organic (certified Organic management practices),
- Soft (organic techniques used when possible but also includes IGR’s and other selective pesticides), and
- Conventional (organophosphates and other non-selective insecticides used ).
We used beating trays to sample for adult pear psylla and predatorsin the orchards, and we collected spur and leaf samples for in-lab evaluations of psylla nymph and egg densities, and mite densities (Two-spotted spider mite, European red mite and Pear rust mite). We placed a Delta trap with pheremone lure in each block to monitor codling moth flight, and evaluated codling moth fruit injury at mid-season and just prior to harvest.
In 2003 we more than doubled our sampling effort over 2002, increasing sampling frequency and the number of sampling sites. This allowed us to provide the growers with information about the densities of pests--particularly Pear Psylla and Codling Moth--in their orchards throughout the season. The weekly pest monitoring information was published on this web site, as well as on a public information billboard at the Nicholson fruit stand, located at the northern junction of Campbell Rd. and Hwy 97 in the Peshastin Creek valley.
Pear psylla densities—adults, eggs, and nymphs—were much lower in all three programs in 2003 relative to 2002. There were greater adult pear psylla densities in the Organic program relative to the Soft and Conventional programs, although the difference occurred near harvest. Pear psylla nymphs, the damaging stage of pear psylla, were kept below the economic threshold by all three programs.
Pest pressure from spider mites was low in 2003, and management was consistently effective. However, pear rust mites were problematic in the Soft and Organic programs, as there are no effective Organic tactics for post-bloom control of pear rust mite. Inadequate early-season (prebloom) pear rust mite control led to severe economic damage in three related Organic blocks. The lack of available postbloom interventions for pear rust mite remains a limitation to selective programs.
Codling moth pressure was remarkably high in several Soft and Organic blocks. In Soft blocks, the use of Intrepid in combination with mating disruption was successful in controlling the pest. For Organic blocks, Entrust was used in combination with codling moth virus (Cyd-X) and mating disruption. This tactic proved very effective in controlling very high pressure.
The implementation of Organic and near-organic Soft pest management strategies over a two year period has been successful in managing pests relative to Conventional strategies. Further analyses are currently being conducted to determine the effects on fruit yield and quality, cost and return, and grower satisfaction. Results from these analyses as well as a third year of study will provide better determination of the feasibility and benefits of implementing organic and soft programs on an areawide scale.