Decisions to be made at T3 treatments

With many wheat crops suffering from drought and reduced yields predicted as a consequence of this, fungicide inputs at T2 have, in many cases, been lower than usual and growers face a difficult decision on what to do for the best at T3.

"The T3 treatment targets ear diseases and also at keeping the top two leaves free from disease. Cutting back on fungicide inputs at T2 will mean that any rainfall between now and harvest or any cereal aphid infestation will encourage ear disease and subsequent risk to grain yield and quality. With reduced crop height and a tight top crop canopy, any disease could easily spread quicker than usual, given suitable weather conditions. Because of reduced crop potential, it is inevitable that growers will be considering their T3 options more carefully and will want an effective but realistic option in the context of a difficult season. Wheat is still a very valuable crop and, even if overall yields may be down, growers will want the assurance that their grain quality can be maintained," says Dr David Stormonth, Technical Manager for Interfarm UK Ltd.

David points out that mancozeb is regarded as the original and classic ear treatment and it is still the realistic option to consider today. "Mancozeb, either as a straight in Quell Flo or as a coform with chlorothalonil in Guru, was re-registered this year. The new efficacy data from the re-registration packages shows that its disease spectrum extends beyond Septoria protection to include robust protection from ear diseases, including Fusarium, Microdochium and sooty moulds, mildew, brown rust and yellow rust. Quell Flo is not only a low cost option, but also a highly effective option, alone or in mix with a low rate triazole or strobilurin, depending on disease pressure or final grain markets."

David advises growers to assess their disease and mycotoxin risk when deciding on their T3 treatment and timing. "Bread making wheat needs more comprehensive protection against Fusarium species in order to prevent mycotoxins. These crops may also require a T3 to be applied earlier between full ear and the start of flowering."

"The re-registration of Quell Flo and Guru means that growers can still integrate effective low cost multi-site fungicides into their disease programmes and be assured of strong protection against the key ear diseases," concludes Dr Stormonth.