With delays to wheat winter harvesting in some parts of the UK now looking set to push back winter oilseed rape sowings too, growers will need to turn to varieties with strong autumn vigour to make up for lost time.
ADAS harvest report 5 reported that by 25th August harvest was only 45% complete, compared to the five year average of 60%. Rate of progress slowed over the last week, with harvest limited to just a few days, mostly in the Eastern region and the East Midlands.
Bayer CropScience product manager for seeds Sarah Middleton says the frequent rainfall experienced in August 2015 could also trigger spore release from old stem cankers and we could be faced with an early Phoma epidemic, which can be damaging to later-sown crops.
Her advice is; “Count the number of days in which rain falls from 1 August to determine when phoma infections are likely to start in oilseed rape. A key driver for phoma is the rainfall pattern in August and September – rain is needed to produce airborne spores. Just 20 days of rain – even as little as 0.1mm – are needed to trigger phoma infections. It’s worth ticking off the days with rain from 1 August and you need to be tuned in to early epidemics. Spores are everywhere in the environment and the consequences of early Phoma infection can be very severe – it is not just what you do on your farm that matters”
Hutchinsons’ technical development director Dr David Ellerton says the delays to winter wheat harvesting are bound to have a knock-on effect on winter oilseed rape sowings. “It’s now highly likely that some growers will have to sow a significant proportion of this autumn’s crops in the second half of September,” he says.
“For plants to reach the ideal eight leaves stage before winter, the autumn vigour of a hybrid such as Fencer will be essential. It offers the flexibility of sowing date that’ll be needed this autumn and has excellent Phoma resistance.
“It’s really hard to control Phoma in late sown smaller plants of a susceptible variety since it takes little time for the fungus to migrate from the leaves into the stem. However the larger, faster growing plants from a resistant variety are much easier to manage.” On the 2015/16 HGCA Recommended List for winter oilseed rape in the East/West region Fencer is unique in combining the leading Phoma resistance score of 8 with market leading oil content of 46%.
Colin Button, Hutchinsons seed manager, adds that over the last two years of trials, Fencer has been the fastest variety for rapid establishment and recommends the variety specifically for these later and more challenging situations.
It’s autumn vigour and ability to retain both seed yield and oil content in late-drilled situations was quantified in an ADAS vigour/variety experiment over the 2013/14 crop year when two Bayer InVigor hybrids – Fencer and Harper – were compared against two Bayer conventionals; Patron and Rinker. The normal sowing date was 9th September and the late sowing date was 17th September.
Fencer rapidly puts on leaves in the autumn and by November had the highest GAI of the late sown plots. Its seed yield was least affected by late drilling, only losing half a tonne off its ‘normal’ drilling date yield of 5.29 t/ha. Seed yields decreased the most with delayed drilling for the two conventionals that lost 1.26 and 1.48 t/ha respectively. Fencer only lost 0.2% in oil content, compared to more than 1% in the conventional varieties. This study was repeated at multiple sites by Bayer CropScience in 2015 with the same pattern of results.