In wheat well-timed T0fungicides have helped keep septoria and rust in check until the application ofT1. Later-drilled crops or others not receiving a T0 should be closelymonitored until a well timed T1 fungicide is applied during the emergence offinal leaf 3.
It’s too early to assess the full impact of April’s weather ondisease development this season. However, all varieties are showing septoria lesions on their lowerleaves, and yellow rust threatens susceptible crops.In some crops large yellow rust focideveloped before the T0 application was applied, hence latent infection maycause the problem to look worse before activity of the T0 becomes apparent.
Mildew infection is low due to the cold weather, but don’t allow the disease to establish in areas or varieties with a knownrisk.The T1 fungicide timing for winter wheat is approaching; many crops will be ready for treatment during the last week of April. In lots of crops the gap between T0 and T1 will be 2-3weeks, which is usually ideal. Until T1 keep monitoring yellow rust prone varieties e.g. Robigus and Oakley to ensurethe crop has adequate protection.
T1 fungicides are usually applied during the emergence of final leaf 3, this usually coincides with GS 32.However, it’s always best to check leaf emergence by peeling back leaves.In some crops particularly those that are late-drilled or backwards the plant may “drop a leaf” and consequently leaf 3 emergenceoccurs at GS 31.T1 product and dose should be selected according to disease risk and varietal susceptibility, don’t forget many widely grown varieties are susceptible to eyespot.
Other crops are growing well;check bean crops for pea and bean weevil damage, many winter beans are alsoshowing early chocolate spot symptoms which will require timely treatment. Start planning sclerotinia sprays inrapseed; accurate programming of these will depend on the combination oftemperature and rainfall at early petal fall.