How these six agronomy tips will keep your crops on track in June

Crop Progress

Rain in May has made crops take off, which are more forward than usual at this time of year. It’s possible that we could be heading for an early harvest.

With a bit of warmth and the rain disease could take off during June, but generally crops still look to have good potential.

Tom’s agronomy tips for June and July

1. Delay senescence for as long as possible in wheat

With wheat crops rushing through growth stages, don’t get caught out with ear spray timings – there are some varietal differences to be aware of too.

If you’re targeting Fusarium and Microdochium, ear sprays are best applied at early to mid-flowering regardless of whether that is only a short gap from the flag leaf application. If you’re only concerned about topping up foliar disease control there is a little more flexibility with timing.

Keeping leaves green for as long as possible, delaying senescence, has been shown to protect yields, and with the forward crops and high wheat prices potentially this could be vital this season.

That could lead growers to consider an SDHI fungicide at T3, if they haven’t made two applications previously in the programme – for example, by using a fenpicoxamid product at T2.

Aviator (bixafen + prothioconazole) is a good option in this situation. The SDHI element, bixafen, will provide protection against foliar diseases, such as Septoria and rusts and some physiological benefits to the crop, including prolonging greening, while prothioconazole also controls Fusarium and Microdochium, as well as helping against the foliar diseases.

If you’re targeting Fusarium with Aviator, a rate of nearer 1.0 L/ha will be needed to provide the 150 g/ha of prothioconazole needed.

Where two SDHIs have already been applied, then options include Proline (prothioconazole), Prosaro (prothioconazole + tebuconazole) or Firefly (prothioconazole + fluoxastrobin) where the tebuconazole or strobilurin will help against brown rust.

2. Consider second spray for disease control in spring barley

Spring barley crops are growing rapidly after the rain in May, with earlier drilled crops especially looking to have good potential.

At current barley prices, protecting them from the increased disease risk from the wet weather will be important. Most will have applied one spray during May. A follow up application at awns emerging during June of either Siltra (bixafen + prothioconazole) or Ascra (bixafen + prothioconazole + fluopyram) will help cover disease threats.

If you’re particularly worried about Ramularia Ascra is the stronger choice, providing you haven’t used it at T1 as you can only use it once in a programme. Adding folpet is also an option for potentially increasing Ramularia protection.

3. Protect potato crops from both forms of blight

Potato crops add a lot of growth in June and will need protecting from blight. Use the Hutton Criteria and alerts to help guide when there is high risk of late blight and think about how you’re going to structure programmes.

There are fewer options with activity against tuber blight, so it’s worth considering how you will finish programmes, while staying within maximum number of application restrictions.

Infinito (fluopicolide + propamocarb) has good activity against foliar and tuber blight and can be used at any stage of the programme, generally from canopy complete onwards, but you have a maximum of four applications of 1.6 L/ha.

A good strategy is to plan to use Infinito in alternation with complementary fungicides from canopy complete to haulm destruction. Tuber protection can be optimised by building it up from shortly after tuber initiation.

Alternaria or early blight is becoming an increasing threat, thanks to more susceptible varieties, greater occurrence of favourable conditions during early season and withdrawal of products that gave effective control. There is also resistance developing to strobilurin fungicides.

In the past growers were able to rely on incidental control from products targeted at late blight but this is no longer the case. Caligula (fluopyram + prothioconazole) gives very high level, but specific, control of Alternaria and not late blight. It is the top performing product in Euroblight trials.

Apply Caligula at first signs of disease and repeat at a 10-day interval. No more than two consecutive applications can be made, with three in total.

4. Protect untreated sugar beet crops from aphids

The beet industry has successfully applied for an Emergency Authorisation for Movento (spirotetramat) to be used to control aphids transmitting virus yellows, but with some key restrictions.

The key ones are it can only be used on sugar beet crops grown from seed not treated with Cruiser (thiamethoxam), and can only be used as a third foliar spray in the programme after treatment with flonicamid and acetamiprid.

Obviously, it should also only be used if the relevant threshold of one green wingless aphid per four plants up to 12 true leaves, or one per plant between 12 and 16 TL have been reached.

Don’t expect rapid knockdown of aphids – because of its mode of action it might be 3-7 days before you see obvious control.

5. Timing is crucial for oilseed rape desiccation

Uneven ripening of oilseed rape can make it a challenge to harvest efficiently, so a pre-harvest glyphosate application can help make that easier.

It’s important not to go too early as that can not only reduce yield, which isn’t advisable in any year and not least this one with the current commodity prices, but also reduce oil content and increase red seed numbers which can lead to rejections.

Fortunately there is a simple visual test to check whether seeds are at less than 30% moisture content. Look for an area of the field that is representative, take 20 pods at random from an area of canopy that is typical of the field maturity, and then open each pod. If at least two-thirds of the seeds per pod have changed from green to brown in at least 15 of the pods the earliest correct stage for spraying has been reached.

Remember crops that will be used for seed should not be treated, and there is a statutory 14-day harvest interval, although up to 21 days might be required before you can combine.

6. Check out new oilseed rape varieties

With sky high oilseed rape prices currently there’s likely to be a bit more interest in the crop again this autumn.

Dekalb has a wide range of varieties to suit most situations, including DK Expose which will be a candidate for the AHDB Recommended List this autumn, which has been the highest yielding variety in our European network.

It’s a later maturing variety, which is well suited to drilling in early August, and has good disease, pod shatter and TuYV resistance.