Strobs are key to unlocking your OSR yield potential

Article taken from Agronomist & Arable Farmer

Prudent use of OSR fungicides for controlling sclerotinia, and the canopy management of forward lush crops using nitrogen and plant growth regulators, is a pre-requisite to maximising gross margins this year, says Agrovista agronomist Simon Vaux.

“Don’t treat oilseed rape as a Mickey Mouse crop as the potential is huge.  A 5 tonne per hectare crop is the same in terms of profit as a 10t/ha wheat crop.

“This is easily achievable provided you put in the appropriate level of crop management.

“If you are trying to manage black-grass in rape don’t cut corners – or don’t grow it,” he says.

“Oilseed rape is an expensive crop to grow and we would expect to see fungicides account for about £87/ha of the budget, with herbicides accounting for between £100 to £125/ha, especially where black-grass and cranesbill are the problem.

“Oilseed rape crops could need five fungicides this season – two for phoma and light leaf spot, one PGR at least and two sclerotinia – so I don’t recommend growing it unless you’re prepared to manage the inputs appropriately.”

Optimum Canopy

The key to maximising yield, Mr Vaux, is to build an optimum canopy to maximise photosynthesis efficiency at flowering in order to maximise seed numbers.

“We achieve this by applying Caryx which helps prevent apical dominance.  We are looking for 6-8000 pods/m².”

Unlocking the potential of the crop could lead to higher and more consistent yields.  The theoretical yield is 10t/ha, he says, but currently it is only about 5t/ha with the hyrids and some conventional varieties.  Fungicides play a major part in tapping into this potential, although sclerotinia can take out a least 30% yield if badly timed or ignored.

However, the demise of the cornerstone fungicide flusilazole will see programme costs increase further, Mr Vaux believes, but with the potential for much higher gross margins, oilseed rape needs to be taken seriously in the rotation.

“Sclerotinia is so massively damaging and for the relatively small cost to keep on top of it with a strobilurin fungicide such as Galileo (picoxystrobin) it’s a no-brainer,” he explains.

Robust Programme

Agrovista’s advice is to adopt a robust two-spray programme based on Galileo as a first spray at yellow bud (early flowering) followed by a second spray two to three weeks later in high disease pressure situations with Recital (fluopyram + prothioconazole) for alternaria, late mildew and extra light leaf spot control.

“Strobilurins are also known to give a positive physiological benefit to oilseed rape crops even in the absence of disease,” says Mr Vaux.  “So where Galileo has been applied even in a low sclerotinia year it more than pays for itself, making financial sense to always apply the fungicide.

“Galileo encourages better nitrogen uptake by increasing the plant’s ability to scavenge; it provides early control of sclerotinia; and extra greening makes the plant better able to utilise nitrogen.”

In Agrovista trials picoxystrobin also appears to have some activity on verticilium, which is becoming more of a problem where rotations are tight.


17 March 2014

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