East: T1 wheat fungicide choices imminent

This part of East Anglia received no more than 4mm of rain in March so the best input for crops – especially spring crops – would be some decent rainfall.  Nevertheless, crops have been growing and developing rapidly during the last couple of weeks of warm weather.

Most wheat crops had a good T0 fungicide, which included a triazole component. Decisions on T1 fungicides will depend on weather conditions in the run up to leaf 3 emergence and forecast conditions shortly after.

Strobilurins are likely to feature at T1, especially on rusty wheats, second wheats and milling varieties. UAP trials since 2000 have shown that strobilurins improve utilisation of nitrogen, thereby increasing yield and grain protein.

Oilseed rape crops, apart from a few backward ones, are into early flowering stages and will shortly be sprayed with their first protectant fungicide aimed predominantly at sclerotinia.  Sclerotinia pressure seems low at the moment, but it can build rapidly even in dry conditions, as 2007 proved. 

Although pollen beetle appeared comparatively early this year and at high populations, most insecticide treatments worked well – even pyrethroids in many cases in an area of high resistance risk. Backward crops and uneven crops may well need a follow-up insecticide treatment as pollen beetle numbers are increasing again in warm conditions. 

These situations are more likely to warrant a neonicotinoid insecticide where thresholds are breached as previous pyrethroid use will have selected for resistant individuals.

Spring beans have emerged well with sufficient moisture available after drilling. Weevil have been treated once and may need treating again if pest pressure is high.

Spring barley and sugar beet are variable, depending on seed-bed conditons at drilling and how well moisture was retained during cultivations. Evenly emerged spring barley is being sprayed for grassweeds and will be followed up with a broad-leaved weed herbicide and T1 fungicide in due course.

Sugar beet is at cotyledon stage with areas not yet chitted but weeds are emerging regardless. Post-emergence herbicide programs are underway with desmedipham featuring in present dry conditions. Thankfully, we haven’t lost any beet to windblow in this area.

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