West: Recent rain splashes septoria up the wheat canopy

Hopefully by the time this article is printed the bulk of my T2 fungicides will be applied if the weather plays ball. April’s dry spell, with only 20mm of rain in the whole month, was replaced with a wet start to May. Over 50mm accumulated in the first two weeks, with several rain events of over 10mm.

These events will have caused significant rain splash from septoria infection I was finding on eventual leaf 4, so although at the time of writing the top three leaves of wheat crops are fairly free of septoria lesions, I am sure we have latent infection yet to express itself. Therefore my preferred choice of SDHI/azole will be one that has a robust azole dose, as we must try to prevent resistance dulling the activity of this valuable chemistry.

Grassweed control has been relatively pleasing. Fortunately, I don’t have farms with widespread blackgrass problems, it is mainly restricted to the odd field on some farms, but where Alantis (iodosulfuron + mesosulfuron) has had to be deployed it has worked well. I have even been pleasantly surprised with blackgrass control in some winter barley where I feared the worse, but a robust flufenacet residual followed by some pinoxaden (Axial) and the crop is not a forest of slender foxtail heads. Pyroxsulam usage is more common on my farms for brome and ryegrass control and this season efficacy seems to be pretty good. It can be variable, as it is always a balancing act of weed size and temperature.

Winter Barley crops look to have reasonable potential, with disease control strategies working well so far and most crops have good green leaf area from ear to ground. I remember writing this time last year when barley looked the pick of the cereal crops. They look promising again this year, but the dry April has caused some delay in nitrogen uptake, so that they are not as well tillered as last year. With head number being key to yield in barley, I’m not sure they will perform as well as last season.

Interestingly the hybrid barley crops look significantly better than traditional 2–rows, so I think there will be a bigger difference between them this harvest. However, I have less acreage of hybrids this year with growers not prepared to pay the higher seed and growing costs with current crop prices.

Winter oilseed rape crops look promising. They are holding onto good green leaf area, with light leaf spot control strategies holding up, but they are the most difficult of crops to predict performance. Sclerotinia risk has increased recently in my region, with petal tests showing high levels (93%) positive with inoculum. Recent warmer night time temperatures and with petal stick there is an infection risk my, so my mid-flowering spray I hope will have protected against any recent infection events.

Flowering is coming to an end, so I do not plan for a second flowering spray. With current crop value it is difficult to justify. All the yield is formed post flowering in rape, so we need some good light levels over the next few weeks for these crops to fulfil their potential, otherwise cost of production figures for this crop is going to make unpleasant reading at the end of the season.

Spring cereal crops have really benefited from the recent rains and are now starting to romp away, so fungicide and plant growth regulator programmes are starting, with broad-leaved weed herbicide added where necessary. However, maize emergence has been slow and with some crops looking pale as a result of lower than average temperatures, maize more than other crops needs some warm weather. At least the recent rains should help the pre-emergence herbicides’ efficacy.

We are getting to the time of year when the role of the agronomist is more than ever reliant on Mother Nature. We hope to have set up crops to efficiently capture light levels, but need the big yellow ball in the sky to make an appearance and hope that April was not our only good spell of the summer!

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