North: 6 pointers for agronomy in the north in August

Crop Progress

Wheat is still holding on well in Yorkshire with some green leaf showing at our trials site at Cawood, as this is written. Some winter barley has been cut, and yields, while average, have perhaps been better than expected. Potatoes and sugar beet are both at full canopy development. Virus yellows is being found in lots of sugar beet crops in eastern England, but maybe not quite to the same extent in this area yet.

Adam’s agronomy tips for August

1. Watch out for secondary growth in cereal crops

The rain since the spring drought broke in June has encouraged some secondary tillers to develop in cereal crops, including winter wheat and winter barley, as well as spring barley, which will make getting the timing right for harvest more tricky. That make spraying a pre-harvest Roundup (glyphosate) desiccant more likely this year. Perhaps surprisingly the very late drilled wheats, however, are more even.

2. Use moisture to help get oilseed rape away

A lot of growers are still to make their minds up about whether to plant oilseed rape again. Cabbage stem flea beetle certainly moved further north last season, with even some crops in North Yorkshire being attacked and written off.

Anecdotally, there have been larger differences between hybrids and conventional varieties, with more larval damage in conventional varieties grown at higher seed rates in the spring. That’s similar to the results from our CSFB management survey earlier this spring.

Ultimately I think it is likely to be whether there is moisture around mid to late August that determines how much oilseed rape is planted. Make good use of that, and conserve it by rolling and applying a small amount of DAP starter fertiliser to give the crop as good a chance as possible of establishing.

Our Dekalb Establishment Scheme can also give some extra support if you’re growing one of three hybrids – DK Exstar, DK Extremus or DK Excited. All three have been chosen because of their good autumn development characteristics. To participate in the scheme you register via your seed supplier, and for any crop that is sown before 20 September, which fails before 31 October 2020, you will receive a credit of £100/bag of seed.

3. Follow up initial sugar beet disease control sprays

Initial sprays for foliar disease control in sugar beet are likely to be going on as this is written in late July. Follow up sprays should be no more than 28 days later, but there is some flexibility for Escolta (cyproconazole + trifloxystrobin) rates depending on intended lift dates.

For crops going to be lifted after the end of October, a full dose of 0.35 l/ha should be used, but a half dose could be appropriate before then. In trials the second spray of the programme has lifted yields by a further 5t/ha over just one application.

4. Practice good bolter management, especially in Conviso varieties

Most growers who tried the ALS herbicide-tolerant Conviso Smart sugar beet system did so because of problems with weed beet, and feedback has been excellent from growers, with good weed and weed beet control.

But it is important to continue to follow good practice with the system, and in particular manage and remove any bolters to maintain the benefits of using the system for weed beet infested land.

Where hand-pulling is necessary in any sugar beet crop, not just Conviso ones, make sure you follow the stewardship guidelines introduced in 2018 for recording bolter pulling and protecting workers spending long hours in the field.

5. Incorporate tuber blight control into blight programmes

Blight programmes are ongoing with the crop at full canopy. At this stage of the season you’re looking for a good balance of foliar and tuber blight activity. While there are a number of good actives for the former, with resistance to fluazinam, there are fewer for tuber blight.

Infinito (fluopicolide + propamocarb) is one product that does have good activity against both, as well as providing curative activity against blight.

With an unsettled weather forecast as we head into August, and more highly aggressive strains of blight in the population, it will pay to keep on top of blight programmes.

6. Follow best practice to get weed control pre-cereals off to a good start

Following best practice stubble management will help growers take advantage of the best annual opportunity to control grassweeds. Our research shows that best control comes from two stubble applications of Roundup (glyphosate).

Ideally grassweeds should be at the 2-3 leaf stage, and to avoid repeat applications to surviving weeds, use cultivation to incorporate weeds before a second application, if necessary. As ever, using good application techniques will help keep efficacy high.

There will undoubtably be some growers wanting to drill earlier this autumn after the problems of last season. Delayed drilling remains a good tactic for managing grassweeds, but if you do drill earlier there are two new actives available this season.

Octavian Met and Alternator Met (flufenacet + diflufenican + metribuzin) can be used both pre- and post-emergence in both winter barley and winter wheat. Before the end of September it can be used at a rate of up to 1.0 L/ha; after then it’s up to 0.5 L/ha until the end of November. With the contact activity of metribuzin added, it is helpful against annual meadow grass, poppies, groundsel and cranesbill, which are becoming more problematic to control.

Proclus (alconifen) is for use pre-emergence in wheat only, and will be mixed with Liberator (flufenacet + diflufenican).