How southern growers can look after crops effectively in April

Crop Progress

Early drilled wheat crops are making growers and agronomists think hard about growth regulator programmes. September drilled Extase, in particular, is thick and lush and will need some slowing down.

Our CropCheck national snapshot disease testing in Devon is showing quite a lot of Septoria on Graham in the lower leaves. It’s been a mild winter with plenty of rain events to splash the Septoria around the crop.

Most agronomists are recommending growers to apply a T0 on virtually all crops – the exception being the likes of late drilled Extase. These were due to go on in late March or early April.

Matt’s agronomy tips for April

1. Identify the correct timing for T1

Timing is crucial for T1 applications in wheat, and there’s nothing better for identifying when final leaf three has emerged than getting out a penknife and dissecting plants to count leaf layers. If you apply T1 to leaf four it is a long time to wait until the flag leaf spray with no protection on leaf three.

As well as Septoria and yellow rust, eyespot could threaten this season after the mild winter, especially in second wheats.

Ascra (bixafen + fluopyram + prothioconazole) can cover all those diseases, plus mildew and help suppress stem-based Fusarium making it a good all-round choice.

In a protectant scenario, the dual SDHI chemistry in Ascra are complementary and help protect against Septoria sensitivity shifts, and provide strong efficacy. Ascra more than held up against newer chemistry last season.

In addition the Leafshield formulation helps with rainfastness, quick drying on the leaf and physiological benefits.

2. Reduce risk of winter barley shedding tillers at T1

Yield is set in winter barley by the number of viable ears it produces – filling grain sites is not usually limiting unlike in wheat, so preventing the plant aborting tillers at this time through either lack of fertilisation or disease infection is crucial.

Ascra is now available for the barley crop, bringing extra disease control particularly of net blotch and Rhynchosporium. You can only make one application in barley crops, so there is a choice of either using at T1 to keep crops clean and reduce stress or leave it until T2 where its extra activity on Ramularia could be useful.

My recommendation in most situations would be to use it at T1. Ramularia is expressed once the crop is stressed, so using Ascra at T1 can also reduce stress, as well as give good disease control, through its physiological effects on the plant, such as increasing drought tolerance and helping use nitrogen more efficiently.

Ascra also has winter oats, rye and triticale on its expanded label, making it a good option for T1 rust control in those crops. If you’re growing multiple cereal crops, Ascra makes for an excellent one product solution across the crops.

3. Remember Liberator is pre-emergence only in spring barley

Spring barley drilling was getting going in earnest in late March after a few growers tried to drill some in February. Hopefully it will get some moisture underneath it and away it goes.

If you’re still drilling in April remember Liberator (flufenacet + diflufenican) now has an on label approval for weed control in the crop at 0.3 L/ha, but it is pre-emergence only unlike under the old EAMU.

Disease control might be due towards the end of April depending on how quickly it goes through the growth stages. You’re looking for mid to end of tillering for T1 sprays.

Siltra (bixafen + prothioconazole) is a good option for T1 in spring barley at 0.4-0.6 L/ha depending on disease pressure, leaving Ascra for T2 because of the relatively greater impact of Ramularia on spring barley crops.

4. Take care of oilseed rape during flowering

Oilseed rape has fared pretty well this season in areas where you can grow it without too many attacks from cabbage stem flea beetles.

It was reaching green bud during March and moving on quickly towards flowering. A mid-flowering spray of Aviator (bixafen + prothioconazole) at 0.75 L/ha with its two modes of action will help protect against both Sclerotinia and light leaf spot.

With oilseed rape futures prices so positive it will be worth looking after the crop – at these prices you don’t need much of a yield response to profit from your investment. In Forward Farmer strip trials Aviator yielded on average 0.3 t/ha more than the farm’s standard treatment.

5. Take out weeds early in potatoes

Planting of second earlies and maincrop potatoes will be in full swing during March and April. Early weed control is important to reduce competition with the emerging potato crop.

Our residual pre-emergence only herbicide Emerger (aclonifen) makes for a good base to weed control. Adding in Artist (flufenacet + metribuzin) on tolerant varieties will broaden the spectrum and improve grass weed control.

Timing is critical with Emerger – it needs to be on at least seven days before the potato crop emerges. It works mostly by shoot uptake so you need good even coverage of the potato beds to create a film of protection through which the weed grow, picking up the chemical.