An Investigation of Seed Treatments for the Control of Crow Damage to Newly-Sown Wheat

Abstract

Seed treatments for the control of crow damage to newly-sown winter and spring wheat were evaluated in field trials from 2004 to 2007. Treatments included six fungicides, three insecticides, a product marketed as a bird repellent and three possible repellents. Various rates of selected compounds were investigated. Winter wheat was sown in December and spring wheat in late-January to mid-February. Sowing depth was 2 to 4 cm while some selected treatments were also sown at 5 to 9 cm deep. Crow damage was assessed by recording plant density and grain yield. Severe damage by crows was recorded. The plant population for untreated spring wheat seed in 2004, 2005 and 2006 was reduced by 59%, 72% and 89%, respectively. The corresponding reductions caused by crows to winter wheat sown in December 2004, 2005 and 2006 was 97%, 89% and 96%. Best control of crow damage was provided by the fungicide Thiram. Increasing the rate of Thiram applied to seed improved the control of crow damage by increasing plant density in the range 42 to 70% and 36 to 57%, respectively, for spring and winter wheat when compared with untreated seed. Anchor, which contains the fungicides Thiram and Carboxin, also gave reasonably good control. The commonly used fungicide product panoctine gave poor control of crow damage. Other treatments investigated were ineffective in controlling damage. Increasing the sowing depth to more than 4.6 cm significantly reduced damage to both treated and untreated seed when compared with similar treatments sown less than this depth.