Plant 'Em high: to help keep your red raspberry plants from rotting, plant them in raised beds and let those roots breathe

摘要

Root diseases caused by soil-borne species of the Phytophthora fungus are especially difficult to control, and the root rot of red raspberries is no exception. Damage is often more severe either in low areas of fields where water collects, on sites where the soil is heavy, or where the soil is poorly drained. Because of that, it makes sense to plant the berries in raised beds, says Peter Bristow, a plant pathologist at Washington State University's Puyallup Research and Extension Center. Bristow notes that University of California-Davis researchers have demonstrated that the activity of the Phytophthora fungus in the soil is severely impaired when the water content of the soil drops below saturation. In saturated or waterlogged soil (and when the temperature is favorable) Phytophthora forms a spore-producing structure called a sporangium, says Bristow. Drying the soil only slightly by lowering the water table just 8 to 10 inches reduces the formation and germination of sporangia.