South: Crucial to stay on top of septoria at T3

The most advanced wheat crops are starting to boot, but at the time of writing  (May 26) we haven’t got any emerged ears in my area, but they won’t be long coming. Therefore, attention has turned to the T3 fungicide sprays. Disease control to date has generally been good, but this is a high disease year so the risk of septoria and/or rusts coming back in late is high. Where SDHI chemistry has been used at T2 I will be using either epoxiconazole or prothiconazole-based T3 to ensure that we stay on top of the septoria. The real debate will be what to partner with it, as harvest is still a long way off. Where we haven’t already had two applications with a strobilurin, either azoxystrobin or pyraclastrobin would be the obvious choices.

Spring barley is varying between early stem extension and flag leaf emerged, so T2 fungicides won’t be far off. Like the winter crops, they are looking good, so if the weather plays ball the yield potential is good. T2 fungicide will be based around Jaunt (fluoxastrobin + prothioconazole + trifloxystrobin) as net blotch and rhynchosporium are the two main threats.

Winter barley has finished flowering and is starting to fill grains. All are standing at the moment, but some crops won’t need much to push them over before harvest even where highly robust plant growth regulator (PGR) programmes have been used.

Winter oats have ears starting to emerge so are ready for T2 fungicide, and spring oats are at early stem extension. Grassweed control has been patchy on winter crops; some are clean, but some have a lot of blackgrass, whereas the spring crops are all looking quite clean, having benefited from stale seed-beds in the autumn.

Maize is coming up well, but crops are as varied as the drilling date, ranging from 4-5-leaf to not yet emerged. Where pre-emergence sprays have been used, weed pressure is low at the moment so there’s no rush to go through again. However, weeds are emerging as fast as the crops on fields where no pre-emergence was used. These ones will need post-emergence applications at about 3-4-leaf stage. Maize is very uncompetitive at early stages, so yield damage is big if you wait until 5-6-leaf when weed pressure is high.

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