THE USE OF INTERPLANTED COVER CROPS FOR PEST MANAGEMENT IN STRAWBERRIES

Abstract

Non-chemical methods for weed management are becoming important as fewer herbicides are labelled for use and as the market demands pesticide-free produce. We have studied the use of interplanted cover crops in strawberry plantings as an alternative/supplement to chemical weed management. Several different cover crops (tall fescue, marigold and sudangrass) were seeded between rows of newly planted strawberries in late June as runnering was commencing. An additional seeding of sudangrass was made in late July. For comparison, untreated plots and diphenamid treated plots were included in the experimental design. Measurements were taken throughout the season of soil moisture, light levels, crop nutrient concentrations, nematode numbers in soil and crop roots, runner biomass, and weed composition and biomass. Cover crops were incorporated in late fall and the planting was mulched. The following spring, crop nutrient concentrations, nematode numbers in soil and crop roots, weed composition and biomass, yield, individual fruit size, and aboveground strawberry biomass was assessed. The marigolds were too competitive for moisture to be an effective companion cover crop. The early planting of sudangrass was too tall, and fescue was too competitive for nutrients. The untreated plots contained many more weeds than other treatments, nematode levels were higher in the strawberry roots in these plots, and harvesting fruit was very difficult. The late seeding of sudangrass, however, provided significant weed control while not reducing yield relative to herbicide-treated plots.