Find advice for agronomic tasks in the Midlands this August

Maximise post-harvest period for grassweed control

I’d like to think growers are not going to rush in and drill early this autumn, but after the season we’ve had that looks unlikely, understandably. That does mean the period between harvest and drilling is crucial to maximising control of grassweeds before drilling the crop.

Correctly identifying weed spectrums in each field is important. For example, if you have brome, which species, as you’ll manage them differently post-harvest. Meadow, soft and rye brome should be left untouched for a month to ripen before cultivating, whereas sterile and great brome should be buried immediately to stimulate germination.

But with moisture, even with high black-grass dormancy, it should be possible to encourage a flush, with a shallow cultivation of other grass weeds.

Glyphosate applications, which need attention to detail, are then the last line of defence before drilling.

You might also need to look at soil structure depending on your cultivation methods – has you soil slumped? Do you need to do any remedial activity?

Uneven crops might need desiccating

Cereal crops in Lincolnshire and other parts of the Midlands have been incredibly uneven through the season. In some wheats, part of the field was at T1 and others at T2, so using glyphosate to even maturity for harvest might be with considering.

It can also be a first line of defence for weed management, potentially reducing the viability of some grassweed seeds.

Before using Roundup (glyphosate), remember to check with your end user whether it is allowed – it can’t be used on seed crops or malting barley, for example, and then make sure the timing is spot on. There are various tests you can use such as the thumbnail test into grains – if you can still see the indentation of your nail on 20 grains collected from various areas of the crop, it’s below 30% moisture content.

Soil moisture looks favourable for OSR establishment

While, given the tricky year for oilseed rape, I suspect the area planted might fall again, ironically conditions look relatively decent for the crop heading into August. Lack of moisture doesn’t look like it will be a critical factor for establishment, although cabbage stem flea beetle pressure is pretty much guaranteed at some point during the month.

Prices are a little under the minimum of £400/t I think is needed for risk management currently, but we need break crops and there aren’t a huge number of decent choices. Beans, for example, don’t give you the same level of grassweed control and have fewer good herbicide options.

I might have to eat my own words, but I genuinely think it will be a good year for oilseed rape.

For varieties, look for ones with good autumn and spring vigour and a decent disease resistance package. We have several Dekalb varieties that will fit those criteria, including a new one DK Excentric. It has faster than average autumn development, double Phoma resistance, pod shatter and TuVY resistance, and strong standing power.

It’s available through the Alliance group and United Oilseeds. Other varieties with many of the same traits are available through other distributors.

All DK varieties also come with our establishment guarantee. To qualify you need to sow your crop before 20 September, register it on our website https://cropscience.bayer.co.uk/dkestablishment/# by 30 September, and submit any claim through the participating seed supplier by 31 October. Upon validation, your seed supplier will credit you with up to £100/bag for total establishment failures of blocks of 6ha or more.

New option for sugar beet disease control

Sugar beet crops look really well, despite the late drilling, as we’ve had ideal spring conditions. That could mean three-spray fungicide programmes are an option this season, depending on lifting dates, with rust already being found in some crops.

This season, we have a new – well partly new – option available in Twist (trifloxystrobin). Trifloxystrobin was one-half of previous market leading fungicide Escolta (cyproconazole + trifloxystribin) and will make an excellent partner for other azole-based options, such as mefentrifluconazole.

Keep an eye out for BBRO alerts for Cercospora in August – if it gets into crops, it can spread rapidly. Our other sugar beet fungicide Caligula (fluopyram + prothioconazole) has decent activity against this disease, but note it can only be used from 1 September. In BBRO trials we’ve seen yield increases of 3-7.5 t/ha from the use of Caligula as a third spray in a programme.

Prime blight conditions put pressure on choices

The middle of July turned into prime blight weather, and the early part of the season wasn’t exactly low pressure. Most growers have been on a solid seven day interval programme all season, with some now moving to five-day intervals.

That’s put pressure on fungicide choices with growers also following advice to alternate different modes of action.

With Infinito (propamocarb + fluopicolide) have two modes of action, excellent foliar blight activity and better end user acceptance this season, it’s probably no surprise it has been widely used already this spring.

But it is also one of the few products that provides tuber blight protection, so if you can save an application for one of the last sprays that might be wise. Remember the total dose you can apply is 6.4 L/ha in a season, which works out to be four applications of 1.6 L/ha.