interaction of annual weed and white mold management systems for dry bean production in Canada

• Published in: Canadian journal of plant science Vol. 91; no. 3; pp. 587 - 598
• Main Authors: Pynenburg, Gerard M, Sikkema, Peter H, Robinson, Darren E, Gillard, Chris L
• Format: Journal Article
• Language: English
• Published: 01.05.2011
• Subjects: annual weeds; beans; boscalid; costs and returns; crop production; cyprodinil; disease severity; fludioxonil; growers; imazethapyr; management systems; metolachlor; Sclerotinia sclerotiorum; seed treatment; thiamethoxam; trifluralin; vigor; weed control; Ontario
• ISSN: 0008-4220; 1918-1833
• DOI: 10.1139/CJPS10127

Annual weeds and white mold (Sclerotinia sclerotiorum) are serious pests in dry bean, and can cause substantial yield losses. The proper management of these pests is essential for profitable production. A 2-yr study conducted at three field locations in Ontario examined the effects of two pre-plant incorporated herbicide programs on weed management and three foliar fungicides on white mold development. In addition, thiamethoxam was evaluated for its ability to alleviate stress caused by annual weeds and white mold. Interactions among disease severity, weed control, agronomics and economic returns were examined. Thiamethoxam seed treatment had inconsistent benefits with respect to plant emergence and vigour, harvested weight, seed weight and economic returns. There were no benefits for the other parameters measured. The premium herbicide program (s-metolachlor plus imazethapyr) reduced weed ground cover, white mold severity and pod drop, and increased 100-seed weight, harvested weight and net economic return compared with the economic herbicide program (trifluralin). The foliar fungicides reduced white mold severity and pod drop, while increasing 100-seed weight, harvested yield and net economic return. Fluazinam resulted in the lowest white mold severity, and the highest yield and treatment return, when compared with cyprodinil/fludioxonil and boscalid in some environments. High weed pressure in the presence of white mold increased disease severity. Where treatment differences occurred, the premium herbicide program and fluazinam foliar fungicide resulted in the highest net economic return to growers.