Yellow rust detected in Essex

Richard Peake, of Harlow Agricultural Merchants, has reported his first sightings of yellow rust this season: "We have just received reports of yellow rust in cv Humber variety, which has a yellow rust resistance rating of 8; this proves what we predicted, that yellow rust will be a bigger threat this year than last."

"There are several reasons for this," notes Mr Peake. "Most growers have continued with the same varietal mix, predominantly based around Solstice and Oakley, both of which are yellow rust susceptible."

"In terms of disease pressure, in this area of the country we would have a major septoria event once in every ten years, but for rust that goes up to four in every ten years!"

"There is also possibly a new race of rust to consider this season; the Claire race. This race started up in New Zealand a few seasons ago and has since been identified in UK breeding programmes – if this takes a hold - almost all of the UK wheat area will be susceptible to yellow rust infection."

"Where crops were not adequately treated last season rust was a problem - in fact one trial plot of untreated Oakley was completely defoliated by yellow rust! Of course, farmers did not experience these levels of disease, indeed most did not see any rust at all, but this was down to robust well planned fungicide programmes starting at T0."

Mr Peake continues: "There is no doubt that with the correct fungicide programme in place, rust can be kept at bay and yield responses are positive. In our trials, varietal responses to fungicide programmes over untreated ranged from 100% in Robigus to 50% for Viscount, 40% for Oakley and 20% for Solstice, so there is no question about return on investment from these inputs."

"We advise our growers to start their programme early at T0 with a low rate of triazole when the Atlantis is going on, followed by a T1 based around a triazole + chlorothalonil, and then a robust T2 centred on epoxiconazole and pyraclostrobin, which are the strongest proven rust products on the market. We will then use a second strobilurin and triazole application at T3."

"As yet, the new SDHI products have not been fully proven in yellow rust situations, so we shall trial them this year, and see how they perform under high yellow rust pressure."

Peter Hughes, Cereal Fungicide Product Manager for BASF adds: "Pyraclostrobin based Comet 200 fits well into programmes at T1 and T2 primarily for its value in trusted rust control, but also proven physiological effects.

In 2010 there was unprecedented use of Comet 200 in programmes at T1 because of the rust susceptibility of varieties in the ground. Based on our research amongst agronomists, we expect similar recommendations for the coming season as risks and varieties remain the same. The combination of epoxiconazole (Ignite) and pyraclostrobin (Comet 200) is proven to give robust control of all the leaf diseases that we’ll see in the UK."

"Comet 200 promotes additional yield benefits in mixes with or without new SDHI’s. On the basis of an 11 trial series in 2010, the yield response from using Comet 200 with new SDHIs was 0.3t/ha, which is worth at least £40/ha in additional production margin based on likely grain prices for 2011. Comet 200 is more than justifying its inclusion in the programme."