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Strobilurin sprays key to unlocking rape potential

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Strobilurin sprays key to unlocking rape potential

09/04/2015

Article taken from the Anglia Farmer

Prudent use of oilseed rape fungicides against yield-robbing diseases such as sclerotinia, light leaf spot and verticilium are likely to be a prerequisite to maximising gross margins this year.

Autumn applications of Frelizon have given excellent control of phoma and light leaf spot, says Agrovista agronomist Graham Edwards.  But those same fungicides have now run out of steam and crops might need a second application for light leaf spot.

The price of oilseed rape has dropped considerably this year, but crops in the ground with good potential will still need protection.  “Yields of 5t/ha are not unrealistic provided there is an appropriate level of crop management,” says Mr Edwards.

For sclerotinia, control growers should adopt a minimum of a two spray programme that provides cover for the whole of the flowering period, he believes.  In addition, this approach could provide cover for other disease such as alternaria and botrytis.

Galileo (picoxystrobin) is the first spray at early flowering, which is the foundation of the programme.  It should be followed by a second spray two to three weeks later with a fungicide such as Recital (fluopyram + prothioconazole).

Picoxystrobin has a similar physiological benefit on rape as strobilurin chemistry has on wheat.  “Keeping the crop greener for longer adds valuable yield, which can be as high as 0.9t/ha, but importantly providing up to 75% sclerotinia control as well,” says Mr Edwards.

“Oilseed rape is not a cheap crop to grow, however, and with some crops requiring multiple fungicide sprays a season, inputs must be managed appropriately.  With all inputs under scrutiny the one not to cut out is Galileo because in the absence of disease it more than pays for itself.”

Galileo encourages better nitrogen uptake by increasing the plants ability to scavenge.  It provides early control of sclerotinia and light leaf spot – and extra greening makes the plant better able to utilise nitrogen.

Sclerotinia is one disease which Mr Edwards says is very much on his radar.  Tighter rotations and overwintered trash harbouring inoculum have seem sclerotinia trash harbouring inoculum have seen sclerotinia in all major oilseed rape growing areas.  It can take out at least 30% yield if sprays are badly timed or ignored.

“Sclerotinia is so massively damaging and for the relatively small cost to keep on top of it with a strobilurin fungicide such as Galileo,” says Mr Edwards.  “It’s a no brainer.