SPEAKER: Dr. Tobin Northfield - Assistant Professor, Dept. of Entomology,

Washington State University, Tree Fruit Research & Extension Center

Wenatchee, WA

Abstract: Fruit trees often rely on pollinators for fruit production, and natural enemies of pests to reduce fruit damage. The ground cover can provide sources of food for beneficial insects in each of these groups but can also serve as sources of pests that reduce fruit quality or production. Here, I discuss two tree fruit systems that differ in the impacts of ground cover habitat on fruit production. In Australian cacao farms, increasing organic matter in ground cover improved each, pollination and abundance of predators, ultimately increasing yields. Thus, providing ground cover habitat may have simultaneously increased two ecosystem services: pollination and natural pest control. However, in US cherry farms, broadleaf plants in orchard ground covers serve as primary hosts for leafhoppers that vector X-disease phytoplasma, an untreatable pathogen that reduces fruit quality. Here, reducing groundcover access to leafhoppers by covering drive rows with reflective horticultural fabric reduced vector abundance, potentially reducing disease spread and ultimately improving fruit quality. These two systems provide examples of the different roles ground cover can play in ecosystem services and disservices.