South: Sclerotinia time approaching

Oilseed rape crops are motoring away, the earliest now showing an even yellow colour. But what has happened to DK Cabernet? I know it is one of the latest flowering varieties on the recommended list, but it seems to lack spring vigour as well.

Most of my oilseed rape crops have recently had a stem extension fungicide applied at yellow bud. Sclerotinia is obviously the next concern. If crops have had a decent fungicide at yellow bud, this will give some protection against an early sclerotinia attack.

My intention now is to apply a proper sclerotinia fungicide two to three weeks after the stem extension spray. If no fungicide was applied at yellow bud then the sclerotinia spray wants timing before the onset of petal fall. Products of choice will be Filan (Boscalid),Galileo (Asoxystrobin) and Topsin (Thiothanate Methyl).

T1 sprays are being applied this week to wheat crops and looking at the weather forecast, they will be applied, except for a few backward crops, by 1st of May. Flag leaves will start emerging from mid May onwards and this should mean a gap of three weeks between treatments which is ideal.

Septoria pressure in the current dry conditions is lower than
in previous seasons, but don’t be lulled into a false sense of security.
Yellow rust is still a major threat.

The cold and dry conditions coupled with recent Atlantis, Pacifica or
Horus applications have certainly pegged growth back and some crops had
the tip of leaf three coming out at late GS 30 rather than GS32! Yet
again this shows the importance of careful crop dissection rather than
growth stage as the decision tool for fungicide timing.

And what of these late herbicide applications? Best advice from
Bayer was to wait until it warmed up. Consequently most people went on
in perfect still warm growy conditions between the 8th and 10th of
April. At the moment these applications don’t appear to be working as
well as they should.

The few people who ignored best advice and sprayed in near
freezing conditions earlier on appear to have got better control. The
only conclusion I can draw from this is that adequate moisture (and a
smaller target) are more important than temperature. Perhaps by the time
all the blackgrass in the country is resistant to Atlantis, we will all
have learned how to use it properly!

See more