West: Keep an eye out for pollen beetle as weather warms

Since last writing the weather has been very slow to warm up, with temperatures only really rising over Easter weekend. This, combined with more wet weather and very strong winds, has meant that crops have been very slow at “getting away”. The wet and windy weather has also meant that spraying days have been at a bit of a premium.

Most rape crops are now stem extending and at the green bud stage. There has been little or no sign of pollen beetle. As the weather warms, this pest will probably become more evident. The evidence so far would suggest that pollen beetle will not reach threshold levels soon enough to be a problem for most crops. Spring T1 fungicides have generally been applied to the crop. As ever, it is almost impossible to tell whether the crops are full of potential or not, but a lot of crops do seem to have a Green Area Index (GAI) that is close to where it should be.

The wheat crops that were drilled early or on time continue to carry very high levels of septoria, with most of the lower leaves now completely consumed by the disease. Continuing wet weather has meant conditions are still good for the development of the disease. This weather has also meant that a lot of T0 applications have not yet taken place. At the time of writing over the Easter weekend, conditions have been perfect for spraying, so hopefully the opportunity has been grasped and the remainder of the outstanding T0 applications have been made. Because the crops are developing more slowly than last year, hopefully this delay will not prove to be too damaging. The important message to growers now is not to delay the T1 application, no matter how short the interval may be between T0 and T1. The T1 application should target final leaf three as it is emerging (usually GS32).

Barley crops are looking well and nearly all crops have had their T0 application, where one was planned, and are now getting very close to GS31 and their T1 application. Rhynchosporium levels have been high this spring, which has been a function of earlier planting and a mild, wet winter. Brown rust is also showing itself at much higher levels than we have seen for a year or two. The message for the winter barley crops has to be “do not take your eyes of the disease ball”.

I have noticed a lot of maize stubbles in the last week or two that are holding a lot of water on the soil surface, where normally the fields would be fairly free draining. This is indicating to me that there are soil structure issues that need addressing before planting the next crop (at this stage of the season probably maize again). Putting these problems right will be key to the success of the next crop.

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