2012 Annual Report
1a.Objectives (from AD-416):
The objective of this cooperative research project is to conduct collaborative small fruit research of mutual benefit to ARS and Washington State University and to coordinate grower field trials complementary to the small fruits research programs at USDA-ARS Horticultural Crops Research Unit.
1b.Approach (from AD-416):
Studies will involve insect collections using sticky cards and water pan traps which will be used throughout the season to establish the phenology of insect development and dispersal. There will be trap plants for virus transmission studies placed in field trials throughout the growing season to determine when viruses are being moved in the field. Plots of raspberry with mixed virus infections will be established at the Mt. Vernon research station. There will also be nematode sampling over the season to study nematode populations after cover crop trials and chemical control trials.
During 2011-12, this project supported research on mixed virus infections in red raspberry and studies on the life cycle of the large raspberry aphid. The large raspberry aphid is the primary vector of two of the viruses in the mixed virus infection studies. The work with the aphid has shown there is a single aphid flight in late June, which provides growers with a means to control the aphid with a single or possibly two sprays rather than multiple sprays throughout the growing season. The mixed infections studies have shown that raspberry bushy dwarf virus together with Raspberry leaf mottle virus has the greatest impact on plant growth. At the same time Raspberry bushy dwarf virus in mixed infections with Raspberry latent virus has the greatest impact on fruit quality, leading to a severe crumbly fruit that makes the fruit unusable the high value fresh or whole frozen berry markets. This work is being followed up with experiments using aphid control based on population peaks to determine how effective this can be in limiting spread of the aphid transmitted viruses. This research was conducted in support of objective 3B of the parent project.