Farmers Weekly Interactive

East: Review of blackgrass contol

Combing peas have received their second fungicide, which included an aphicide plus pyrethroid for pea moth. A second dose of manganese was included for the prevention of marsh spot. Spring beans have, or will be having, their second fungicide, which will include an insecticide for bruchid beetle if required. Vining peas are being monitored for pea midge.

Orange blossom midge did not materialise, even so, there were some prophylactic treatments applied in this area. Pheromone traps were catching large numbers of male midge, but this should not to be used as a threshold to spray, as they are not an indication of what is happening in the crop. They just show that the midge have emerged. It was an interesting result as the yellow sticky traps caught very few female midge. Hopefully HGCA will fund some more research on the use of pheromone traps.

Blackgrass strategies for the season are under review. I  think it is a useful exercise to have blackgrass seed tested for resistance, as once again it is a guide to what is happening in field. Not all poor control may be put down to resistance – a lot may be due to areas of poor crop growth due to  waterlogging caused by compaction or poor nutrient status of the soil.

All these factors need to be looked at. Programmes using triallate seem to be giving the best results and this is being mirrored in trials. It is concerning that programmes are being developed around residual stacking with flufenacet-based products as this is an anilide herbicide, which blackgrass exhibits enhanced metabolism to. This autumn, all my serious blackgrass programmes will include triallate, plus the plough.

As far as wheat varieties are concerned, I’m trying to advise growers not to grow large acreages of wheat that are susceptible to the same races of yellow rust, which is very hard to do when you see the national list. If they do, then they need to grow an acreage that fits the sprayer’s capacity in one day. I will also be recommending the use of a triazole-based seed dressing for those varieties that get seedling yellow rust. This probably goes against the FRAG guidelines for prevention of resistance to septoria, which is still number one disease to contend with in my book.

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