AHDB has issued late-spring guidance for the management of fast-moving cereal crops.
Tim Isaac, AHDB Head of Arable KE, said: “Both the autumn and spring cropping seasons got off to a challenging start and crops are now racing through their growth stages.
“But, with extremes of hot and cold, crop growth has neither been smooth nor predictable this season and this makes field work hard to plan.
“The AHDB website contains a wealth of information but it can be overlooked during the busy late-spring period. So we’re reminding people to take advantage of our resources to make the most out of the 2018 crop.”
Challenging early season weather means many people are playing catch-up with their disease control programmes. To determine the most appropriate time for spraying, people should view the cereal growth stage information published at cereals.ahdb.org.uk/wheatgg
Paul Gosling, AHDB Crop Protection Scientist, said: “In wheat crops, even if the timing interval between T1 and T2 is short, it’s vital to make sure the timing of the T2 is correct. The flag leaf should be fully emerged (GS39). Any delay in treatment increases the chance of infection.
“With hints of declining SDHI efficacy against septoria now evident in some places, it’s also important to include a multisite at T2 to manage resistance and improve control.
“In UK barley crops, ramularia isolates with strong resistance to SDHIs are now also common and SDHIs can no longer be relied upon for control, so it’s important to include chlorothalonil at T2.”
Earlier this year, AHDB published information on ramularia and its control on a dedicated web page – cereals.ahdb.org.uk/ramularia – to help people manage the disease this season.
In June, attention turns to the T3 wheat ‘ear wash’ spray to target fusarium head blight and ‘top up’ foliar disease control on the flag leaf
The decision to spray at T3 depends on many factors, including the weather and the target market, but those spraying will likely turn to azoles. AHDB fungicide performance work shows several are effective (epoxiconaozle, metconazole, prothioconazole and tebuconazole) but T3 sprays can select for azole-resistant septoria strains, even when septoria is not the primary target. In order to protect the azole, a multisite should also be included at T3.
“At T3, take particular care to note any timing and total dose restrictions on product labels,” added Paul.