The Rootstock Working Group is comprised of researchers from plant pathology, genetics, horticulture, pomology, plant breeding, germplasm, cooperative extension, and economics. With this vast knowledge and experience we are using a multi-faceted approach to understand the interactions of soil borne root diseases and pests with perennial nut rootstocks and to disseminate this information to stakeholders while also selecting promising rootstock materials for further evaluation and future release.
A major impetus for assembling this working group is the changing availability of fumigants to combat soil borne diseases. Soil fumigants, such as methyl bromide, were used to reduce the impact of soil borne pests and pathogens prior to planting. However, they were found to have negative environmental effects and then phased out of regular use with few alternatives. Rootstocks with improved tolerance or resistance to the major soil borne pest and pathogens is the most sustainable alternative to soil fumigation. All the major woody perennial fruit and nut crops, such as walnut, almond, and grape, experience significant yield losses in the hundreds of millions of dollars annually due to soil borne diseases. Losses due to disease combined with the reduced availability of soil fumigants has triggered an urgent need in the industry for new rootstock genotypes with resistance to the key soil borne pathogens.
