Find out about Bayer’s advice on some agronomic decisions in April

Crop Progress

Good establishment last autumn and mild conditions up until the end of last year resulted in crops looking well. Most continue to look well with the notable exception of oilseed rape where although some crops are okay many forward-looking autumn crops have succumbed to main stem damage by larvae of cabbage stem flea beetle and rape winter stem weevil. In combination with extended hard frosts this has resulted in growers writing off many crops.

Sam’s agronomy tips for April

1. Be careful around your timings of T0s and T1s in wheat

T0s in wheat crops will soon be upon us at the time of writing and despite a number of frosts since December slowing up yellow rust, it will inevitably rear its ugly head. With March so far being wet, as temperatures increase, Septoria tritici inoculum will be bubbling in the bottom of forward crops, even those with good resistance ratings. We haven’t had a wet start to spring, without chlorothalonil, and if it does stay wet, we will need to be on our game.

T0 decisions impact on T1 – correct T1 timing to protect leaf 3 is fundamental and underpins the whole fungicide strategy. Going too earlier for either/both timings can be a recipe for getting it wrong for T2. Avoiding an interval of no more than three weeks between T0 to T1 is important especially for yellow rust susceptible varieties.

Hopefully contact herbicide applications are complete but if there are any outstanding applications feel free to get in touch for any guidance – any late applications are always a concern to avoid crop damage.

2. Target leaf three fully emerged for T1s in wheat

T1 can be the trickiest timing to get right - target leaf three when it’s fully emerged. The only way to identify which leaf has emerged is to dissect plants – get it wrong and disease control will be compromised later.

At this timing you’re looking for broad-spectrum activity to cover Septoria, yellow rust, mildew and eyespot. Ascra Xpro (bixafen + fluopyram + prothioconazole) at 1L/ha minimum provides yellow rust control alongside strong Septoria activity through its dual complementary SDHI loading. In addition, it will also give good protection against stem-based diseases and mildew to complete its all-round broad spectrum profile resulting in best return on investment. Most varieties will have a genetic weakness to eyespot, which unless it goes dry will be at high risk given relatively forward growth due to soil temperatures remaining high into December as well as a wet January and March – especially second wheats which weren’t ploughed.

As with all the Xpro range the Leafshield formulation gives excellent rainfastness in minutes – useful in catchy conditions – and also physiological benefits delivering yield in the absence of disease if it goes the other way and is dry. Remember that bixafen-containing products increase nitrogen reductase activity improving nitrogen use efficiency.

3. Maintain tiller numbers in winter barley with a T1 fungicide

Maintaining tiller numbers in winter barley is more important than in wheat. Maximising the number of ears is what drives yield, and disease infection at this stage will cause the plant to abort tillers limiting yield.

Some crops may well have had a T0 of prothioconazole, but in any case, T1 gives the biggest response to fungicides. 0.6L/ha Siltra Xpro provides an extremely reliable option for most situations. Ascra Xpro at 0.9L/ha is an option also but can only be used at a single timing in barley crops and can bolster net blotch and Ramularia. Both options are suitable for malting crops. 

4. Protect oilseed rape crops that haven’t been written off

Oilseed rape crops that weren’t written-off, eventually started to extend in the second half of March. As a consequence of forward autumn growth and a wet March light leaf spot is easy enough to find and its crucial to keep this off the buds. While Sclerotinia isn’t a big problem most years, when flowering and petal fall coincides with optimum conditions for the pathogen infection it can be a big yield robber.

An application of Aviator (0.75 L/ha) is the best all round option from green bud through to mid-flowering, covering not only Sclerotinia but also light leaf spot. It also provides physiological benefits to the crop in the absence of disease, prolonging flowering. In farmer strips trials it has increased yield by 0.25 t/ha on average versus the farm standard consistently over the last few years.

5. Earlier is better with weed control applications in sugar beet

A wet March will most likely delay sugar beet drilling in East Anglia. When crops go in they’ll most likely come through quickly, but so will weeds. Early weed control is a key priority but at the same time so is avoiding herbicidal crop effects.

Betanal Tandem (phenmedipham + ethofumesate) is a good broad-spectrum option that can be used from expanded cotyledon stage of the beet with a suitable residual. Consider the conditions at application as warm days and cool nights with large diurnal swings can predispose the crop to herbicide damage.

If you’re growing Conviso Smart varieties, remember earlier as opposed to late is generally the right thing - consider the use of a pre-emergence herbicide to buy a little bit of flexibility over the timing of your one and only Conviso One (foramsulfuron + thiencarbazone-methyl) application. Finally, implementing Conviso stewardship is a must.

6. Two early season potato products a must have

The low dose, operator friendly liquid nematicide Velum Prime (fluopyram) provides good yield protection and potato cyst nematode population management and is a useful starting point for all programmes. In low pressure sites it can be used alone as an affordable option, while under higher pressure use in conjunction with a granular nematicide at either half or full rate of the granule.

With application either on-planter in-furrow or as an overall spray and then incorporated it can fit into most systems without too much hassle.

Pre-emergence product Emerger (aclonifen), which provides a strong backbone for weed control in potatoes, ideally should be applied at least seven days before the crop emerges. It gives good all-round weed control, especially of Polygonum, Chenopodium species and nettles. Add a partner, such as Artist (flufenacet + metribuzin) to provide robust grassweed control.

7. Use FieldView to monitor and measure on-farm trials

Doing your own on-farm trials to compare inputs is a great way to see what works for you. Our digital platform FieldView makes that easy. FieldView brings all your data under one umbrella to enable better analysis and interrogation of data for better more informed decisions. If you’re interested in having a demo, please get in touch.