Contrasting responses of T-2, HT-2 and DON mycotoxins and Fusarium species in oat to climate, weather, tillage and cereal intensity

Analysis of survey data from 804 spring-oat fields divided into five climatic regions suggested that low inoculum level of Fusarium langsethiae was a major limiter of T-2 + HT-2. A 30-year climate with a cool and rainy 10-day period preceding estimated mid-anthesis and a warm 3-week period following anthesis were positively associated with T-2 + HT-2 contamination. In 12 survey years, warm weather from 4 weeks before GS65 until harvesting increased T-2 + HT-2, except in the 1–2 weeks preceding mid-anthesis, when the requirement for high humidity dominated. F. langsethiae and F. sporotrichioides were consistently promoted by high temperature from mid-anthesis onwards. A positive response of T-2 + HT-2 to high humidity peaked 5–10 days earlier and was shorter and weaker than the responses of DON and F. graminearum . The probability of high concentration and regional mean concentration of T-2 + HT-2 tended to be lower under ploughing than under non-ploughing, and they tended to increase with increasing cereal intensity. T-2 + HT-2 was positively associated with zero tillage when compared with minimum tillage. The responses of F. langsethiae and F. sporotrichioides to ploughing and cereal intensity varied by region. In contrast to T-2 + HT-2, DON was the same or higher under ploughing than under non-ploughing, not consistently affected by cereal intensity and not associated with zero tillage. F. graminearum was consistently more common under ploughing than under non-ploughing, and decreased with increasing cereal intensity in four regions. Also, F. culmorum and F. poae tended to be more common under ploughing. F. culmorum increased with cereal intensity in three regions.