The dry weather continues. At the time of writing large parts of my area have received less than 25mm of rain this autumn. As such the seedbeds are still relatively open, and the residual herbicides used to date are unlikely to have created as good a chemical seal as last year.
That said, you can see blackgrass being affected by the residuals. The fact the blackgrass emergence has been delayed, combined with earlier drilling and fewer stale seedbeds could result in a challenging year on some farms.
To help control the annual grass weeds this autumn, I am eager to use a contact chemical such as iodosulfuron-methyl-sodium or pyroxsulam. Both these products will need to be applied with a residual partner.
The majority of the grass needs to be emerged before application of such chemistry. Judging by the amount of blackgrass just under the soil surface this may be at least another 14 days. With the soil moisture deficit being high, even if rain does come it is unlikely to make soil conditions so wet that application is not possible. Temperature is also critical, as the grass weeds need to be actively growing for the chemicals to work effectively.
One of our technical team in a recent bulletin described 2011 as “the year of the pest”, judging by the bird cherry aphid counts this can be justified. I am currently recommending all emerged cereals receive a pyrethroid insecticide with the risk of BYDV being so high. I have also seen frit fly damage in wheat, where least expected.
Now is an ideal time to correct any nutrient problems in cereals and OSR. Rooting will be promoted by the use of products such as manganese, phosphite and zinc. If we should happen to have yet another very dry spring the effort put in to getting the nutrient balance right now will be well rewarded.
OSR crops are presently receiving their autumn fungicide, which is mainly flusilazole or prothioconazole based. With disease being slow to develop this year I was hoping to combine this with the propyzamide application. However as warm dry days are detrimental to the efficacy of that herbicide we may have to separate the applications.