Over the last three years mycotoxin-forming ear diseases have been dominated by Fusarium graminearum and Fusarium culmorum. Monitoring by Fera this year is showing that both species are being found on upper leaves and therefore increasing the risk of these diseases reaching the ear.
F.culmorum tends to develop during the spring on wheat plants on the stem base and leaves – early plant infection correlates with later ear infection. F.graminearum can arrive rapidly at ear emergence as it is more easily wind dispersed. T3 fungicides on quality wheats will therefore be targeting these diseases with product choice being based on co-formulations of prothioconazole and tebuconazole.
Both triazoles are very active on Fusarium species with prothioconazole offering greater persistence. Flowering is the main risk period for infection with wet weather increasing the risk so treatments need to be applied at full ear emergence to cover the flowering period. Otherwise foliar diseases are generally low although recent rainfall – some of which has been intense – will encourage late septoria development. If conditions remain cooler then yellow rust could also appear so varieties with a yellow rust weakness may also be targeted for a top-up fungicide at T3.
Orange wheat blossom midge are being found regularly in both crops and traps. Population levels are always difficult to assess accurately but some pheromone traps in the eastern region have reached threshold. Large acreages of Oakley help to take the pressure off spraying insecticide for midge but it seems that many crops will need protecting again this year.
Bruchid beetle spraying is likely to be completed in the next week or two with the second insecticide spray being applied 7 – 10 days after the first treatment. A run of hot days last week coincided with early pod set in winter beans. Spring beans will mostly have reached the early pod set stage this week. Downy mildew is also appearing in beans and fungicide treatments are being included with the bruchid beetle insecticides to cover chocolate spot, downy mildew and later rust.