Six more jobs to consider before harvest in Scotland

Crop Progress

Crops in southern part of Scotland are more forward than usual, although further north in Aberdeenshire agronomists are telling me they’re more at a normal stage, with wheat flag leaf sprays recommendations likely for early June. In my part flag leaf sprays are likely to be finished by the end of May.

For those who haven’t applied the flag leaf spray as yet, which could have been pushed back because of some windy weather, prioritise this to get it on as soon as possible.

Do watch out for varietal differences in growth stages – Skyscraper for example is very forward, and it could catch you out for spray timings.

Craig’s agronomy tips for June and July

1. Protect wheat crops from ear diseases

Most wheat crops will be at early to mid-flowering from mid-June which is the best timing for ear sprays, especially those targeting Fusarium and Microdochium ear diseases.

Proline (prothioconazole) at 0.55 L/ha will provide good control of those diseases, and Septoria and other foliar diseases at that timing, but there is a long gap between flowering spray and harvest, which can be in September.

Last year we did see a big difference in Septoria levels in June and July, compared with crops further south which will senesce earlier. Continuing to maintain green leaf area for longer will help build yields, which would be sensible in any year, but especially with current prices.

That could push towards using a SDHI fungicide at T3, if you haven’t used one at T1 or T2. Aviator (bixafen + prothioconazole) at round 0.8 L/ha provides a good option for covering all diseases, plus giving some greening benefits from a mid-flowering spray.

2. Consider a second disease control spray for spring barley

Spring barleys were receiving T1s towards the end of May. Overall the crop is well-tillered and has plenty of potential following rain in May, with feed barley prices of around £300/t encouraging growers to further protect it from diseases with a second spray in mid-June.

Later in the season, Ramularia becomes a consideration. Ascra (bixafen + fluopyram + prothioconazole) is a good option with the fluopyram helping out against it, or there is Siltra (bixafen + prothioconazole) which remains a decent all-round product for barley. There’s also the option to add folpet for additional Ramularia control.

Both Ascra and Siltra are fully approved for malting barley crops, and have more timing flexibility than some competitor products.

3. Plan blight spray programmes

Potato crops are just coming through the ground towards the end of May in Scotland.

When planning blight sprays look at the whole programme over the summer. Infinito (propamocarb + fluopicolide) has both foliar and tuber blight activity, so it can be flexible where it can be used in the programme.

But with fewer options to use against tuber blight it is worth considering saving one or two applications of your four applications for later in the programme to help against that infection source.

Where early blight is a potential risk, such as in susceptible varieties, Caligula (fluopyram + prothioconazole) is also available. It doesn’t have any late blight activity, but is Euroblight’s top rated option against Alternaria.

4. Carefully time oilseed rape desiccation

Oilseed rape crops appear to have good potential and harvest can be made more efficient by a well-timed spray of glyphosate to even up ripening and kill off any weeds in the crop.

Timing is key – don’t go too early as that will limit yield, oil content and potentially increase red seeds which can be a rejection issue. To check timing take around 20 pods from across the field, and if two-thirds of the seeds have changed from green to brown in at least 15 of the pods, then it should be ready for desiccation.

You need a decent rate of glyphosate – around 1080 g/ha for desiccation with annual weeds, while 1440 g/ha if there are perennial weeds.

5. Think about oilseed rape variety choice

Early vigour is a key characteristic Scottish growers usually look for in oilseed rape to get the crop away from slugs, and to a lesser extent cabbage stem flea beetle.

A variety which has slower development initially in the spring, as growing away in March can leave it susceptible to frost damage, is also a good trait to look for, but then it does need high levels of vigour later in the spring so it catches up.

Dekalb has a good range of varieties that meet those and other needs, such as resistance to key diseases like Phoma and light leaf spot, pod shatter resistance and TuYV resistance.

A new one to keep an eye on this summer is DK Expose, which our breeder says is the highest yielding variety in our European network of trials and consistent across a very wide area. It’s a candidate for the AHDB Recommended List, although its later maturity might be masking its true potential, and has all the traits you would expect in a DKK variety, including TuYV resistance.

6. Walk crops before harvest to help plan cereal harvest management

It’s important to walk crops before harvest to make sure you know what weeds are present in your crops. We’re seeing more black-grass so be on the look out for it, and think about mapping in tools such as Climate FieldView.

If areas are particularly bad, consider spraying them off – albeit that’s a massively difficult decision to take when prices are where they are. This needs to be done as soon as possible after the weed starts flowering before seed becomes viable.

Using FieldView can help identify patches through satellite imagery, create application maps which calculate exactly how much glyphosate you will require for the area to be sprayed, and if uploaded into the sprayer make application easier and more accurate especially if you have section or individual nozzle control.

Keep rates up at 1080 g/ha of glyphosate to follow the resistance management guidelines for controlling large grass weeds.

For pre-harvest glyphosate applications which help make harvesting more efficient in our wetter climate, 540 g/ha of glyphosate should be sufficient for desiccation and annual weeds, but increase to up to 1440 g/ha if there are perennials present.

Timing for this application is best done by the thumbnail test – take 20 grains from around the field, and if your thumbnail indentation holds in all of them it is ready for spraying. Harvest interval for cereals is seven days, and again don’t spray crops destined for seed.