Beware of growth stages for spring crop performance

Michael Fletcher, Business Development Manager for breeders Limagrain UK, believes that with the range of crop sizes and conditions across farms as a result of the protracted drilling dates, managing crops effectively will require a real attention to detail, focussing on actual growth stages to ensure that PGR’s and fungicides are applied at the correct timings.

"Effectively this season we are looking at managing two crops - those that were drilled early and those that were later drilled – these will develop at different timings and also reflect different challenges."

"Although there is still a lot of winter to come, and many growers may be questioning how much they want to invest in some of the poorer crops, it is still vital to protect yield and take advantage of the early spring conditions to encourage tillering and rooting and keep the plant as healthy as possible through to harvest."

"Experience suggests that it is better to spend a little more at the beginning of the season in conditions such as these, making the T0 more important than ever."

"It’s difficult to know what the season will throw at us disease-wise, however I should think mildew could potentially be a real problem in the spring as backward crops take-off."

"There are bound to be yellow rust spores that have survived the winter which is more of a problem for the less resistant varieties, and it will be business as normal with Septoria tritici, infact this could be a real issue in some of the more open canopies."

"Where this is the case, there is a strong argument for an early protectant such as Chlorothalonil at the T0 across the board, although a triazole may well be needed to broaden the disease spectrum with a mildewicide in the more susceptible crops."

Fletcher notes that managing these different challenges will require prioritising depending on how the season progresses and the respective disease risk: "So consider getting onto the less disease resistant varieties first. For example in a mildew situation, if you’re growing Crusoe (9) or Panorama (7) this will give you some flexibility whereas more susceptible varieties would need immediate attention."

"The wet soils have meant that crops are not throwing roots down and are shallow rooted, which will become an issue if it dries up, so using a PGR at GS30-31, such as Canopy at 0.5l/ha will be critical, not necessarily as a growth regulator, but to encourage tillering and rooting."

Chris Bean, technical manager at Agrii, believes that T0 fungicide timings may change this season with the more normal crops reaching GS 30 at the latter end of March, but warns that later drilled crops could well miss the T0 and romp straight into an early T1: "Critically, don’t rush to get your T0 on in February as this could mean that you miss leaf four (as in some crops in 2012), leaving too long a gap before T1."

"This is not the first time that we have had conditions like this, we faced a similar set of circumstances in 2000, and what is interesting looking back is the positive response to early season fungicides that we had then. In fact we had larger responses from the late drilled, more open crops as a result of the keeping the lower leaves greener for longer because in such crops those leaves become more important."

"This season will be no different, early season disease control remains critical and whatever yield is in the crops will need to be protected."

"Where later drilled crops get early nitrogen, and develop rapidly , mildew will be problematic, and it’s important to remember that in such crops the HGCA resistance ratings become less meaningful. In these crops, it is also important to remember that for optimal tiller and root development, an early season growth regulator with low temperature activity such as Meteor timed to coincide with the nitrogen will be vital."

“A mix of a mildewicide and triazole offers the best solution, as then not only the mildew but also any early season yellow rust and Septoria is dealt with. Capalo tends to fit well, as it contains fenpropimorph and metrafenone for the mildew (and any eyespot present) and a triazole component to deal with the rusts and Septoria. Adjust the dose rate according to conditions: a half-litre dose is the standard but in areas such as the south-west where Septoria pressure is higher increase it to 0.75l/ha.”

"Where growers may be questioning their input costs on the more backward crops, it is worth remembering that the T0 alone can contribute as much as 0.4-0.5t/ha to the final yield, and with an average cost of £12- £14/ha, the T0 more than justifies its cost," he says.