Boost mycotoxin control with Designer

Growers fearful of Fusarium ear blight in wheat crops are being advised that there is a well proven adjuvant they should consider using with their ear-wash triazole to further improve prospects of control.

The Food and Environment Research Agency (FERA) recently advised growers to apply a robust T3 spray at mid-flowering given the increased risk following the unsettled wet weather in recent weeks and there are suggestions that, as the mild weather continues to favour disease spread, a T4 may be necessary.

“We have seen low levels of Fusarium culmorum at all five sites (York, Caythorpe, Morley, Andover and Cirencester) and a reasonable amount of the Microdochium species (nivale and majus) at Caythorpe and Andover, on both stem bases and the leaf layers,” said FERA plant pathologist Dr Phil Jennings.

“Oilseed rape debris from another site in Devon was covered in F. graminearum perithecia (fruiting bodies), so disease will be moving into the leaf layer here too.”

The mild winter is likely to have helped the disease to persist and develop earlier than normal, hence the increased risk, he explained.

The warning has prompted fears of a re-run of 2012 when the wet weather led to an unprecedented level of mycotoxins in UK wheat samples. The UK has a maximum permissible level of 1,250 parts per billion (ppb) for DON and 100 ppb for ZON concentration in unprocessed wheat destined for human consumption, but testing revealed levels far in excess of this and growers were faced with significant deductions as a result.

Prothioconazole is the triazole of choice for most growers when it comes to guarding against the threat of disease and successive trials have shown it to be more effective than other triazoles. What is less well understood however, is the contribution a suitable adjuvant can make to improving control.

Trials performed in Germany, where Fusarium ear blight is a greater problem due to the high frequency of maize within growers’ rotations, has found that Designer, an organo-silicone and latex wetter, can improve control rates by nearly 40% of the fungicide alone.

The message was reaffirmed by FERA last month with a warning that Microdochium and F. graminearum had been detected in the leaf canopy at most of the HGCA monitoring sites and that the continued warm and wet weather would continue to raise the level of risk facing crops.

If growers want to achieve desirable levels of control they should consider the addition of Designer to all ear wash applications, says De Sangosse Commercial Director, Kim Christo.

“Fusarium ear blight is a serious issue that can result in significant yield loss and financial deductions if grain samples are found to contain more mycotoxins than the allowed maximum. The Microdochium that cause infection can exist as stem-based browning while F. graminearum, which also causes mycotoxin production, survives well on crop trash. It will not take much for that reservoir of disease to infect crops with many already well into flowering,” he says.

Much of the advice growers receive however, tends to focus on which product to apply and at what rate, but the contribution that a suitable adjuvant can add to protecting the crop is often overlooked, he says.

“A well-timed application of products based on prothioconazole, tebuconazole or metconazole at T3 and, if necessary, at T4 to wash the ear will remain the basis of advice to growers, but experience suggests its protective qualities can be enhanced with the use of an organosilicone + latex adjuvant, such as Designer,” he says.

“There will even be some instances where previous cropping or heightened local risk suggests a T4 would be advisable and growers should be discussing this with their agronomist,” he adds.

Kim Christo says Designer is routinely incorporated with fungicides from T2 onwards across the continent where the impact of mycotoxins on grain quality is more widely recognised.

“Across successive trials between 2004 and 2007 Designer delivered an average reduction of 33% in mycotoxin concentrations over what the fungicide alone achieved. Performance varied between triazoles, but in all cases it was found to have a positive result,” he says.

An added benefit of including Designer is the improved rain-fastness due to the latex component aided by the organo-silicone which breaks down the surface tension of water to improve ear spread and hastens drying.

“Some growers think that modern chemistry contains enough wetter, but they should compare the two side-by-side to see the difference for themselves,” says Kim Christo.