The Peshastin Creek Project (3 years)
Pear psylla densities were lower in all three programs in 2003 and ’04 relative to 2002. PP pressure was slightly higher in 2004 than in ‘03. PP densities tend to be in higher the ORG program than SOFT and CONV.
Predator densities increased in late-season in the ORG and SOFT programs, which followed increases in PP densities. Predator densities were higher in ’04 than in ’03, as were PP levels. Overall, the low levels suggest orchards managed for PP will never see large numbers of predators; low PP damage thresholds may restrict the prey base to levels too low to sustain substantial predator populations.
Pear rust mites were problematic in the SOFT and ORG programs in 2003. There are no effective organic tactics for post-bloom control of PRM, and inadequate early-season (prebloom) PRM control led to severe economic damage in three related ORG blocks. The lack of available postbloom interventions for PRM remains a limitation to selective programs.
2003 codling moth pressure was high in several SOFT and ORG blocks. In SOFT blocks, Intrepid and Avaunt with mating disruption was successful in controlling the pest. For ORG blocks, Entrust and codling moth virus (Cyd-X) with mating disruption proved very effective in controlling very high pressure. CM densities were much reduced in 2004.
Costs for pest control were similar for all programs, but SOFT programs tend to be more expensive than ORG programs. SOFT programs are also the most variable in cost, possibly due to their higher flexibility.
Over a three year period, Organic and near-organic Soft pest management strategies have been successful in managing pests, and initial results suggest chemical costs for Soft and Organic to be competitive with Conventional. Further analyses are in progress to determine the effects on fruit yield, quality and grower satisfaction. Results from these analyses as well as another year of study will provide better determination of the feasibility and benefits of implementing organic and soft programs on an areawide scale.