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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 ).
Methods
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.
Back to top Discussion
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.
Back
to top Conclusion
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.
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| Peshastin
Creek Areawide Organic Project
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