Australia
March 2, 2015

The Grains Research and Development Corporation (GRDC) is urging mungbean growers to take a proactive approach to powdery mildew control this season to maximise crop yield potential and capitalise on the current bullish market.

Storm rain across parts of the northern cropping region has sparked concern among growers over the potential for powdery mildew disease outbreaks and raised questions over appropriate management strategies.

Pulse Australia’s national development officer Gordon Cumming said infection could occur at any stage of plant growth however development was usually favoured by cooler (22 – 26°C) dry weather.

“Wet leaf surfaces hinder infection and excess rainfall can wash powdery mildew from the leaf surface, but it is often during the drier cooler periods after a rain event that we will see infections developing.

“Infections typically become apparent during February and usually increase in severity during March and April. Significant yield loss can occur if powdery mildew develops before or at flowering, particularly if the crop is under moisture stress by that stage.

“Growers who are concerned about their crop should contact their local accredited mungbean agronomist or Pulse Australia to discuss their specific situation and relevant management options.”

Infected plants typically exhibit a greyish-white powdery growth on the surface of leaves, stems and pods.

While the dominant mungbean varieties grown in the north, Crystal and Jade-AU, are rated as susceptible and moderately susceptible respectively, Mr Cumming warned that infection could still be costly.

“While this resistance means that the disease will develop more slowly than in the older varieties like Emerald and Berken it will still require active management - such as the use of fungicides - when conditions are conducive to its development,” he said.

“Powdery mildew infection will still be economically damaging in our current varieties especially if it occurs prior to or during flowering.”

Pulse Australia currently holds a minor use permit (PER13979) which allows for the use of tebuconazole (e.g. Folicur 430 SC or Nufarm Hornet 500SC) at 145 mL/ha or 125 ml/ha respectively, with a maximum of 3 applications  per crop. Importantly, there is a 21 day with holding period to harvest.

A second minor use permit (PER13605) is also currently held for the use of Sulphur at 3 kg/ha with a nil withholding period to harvest.

“Remember that both of these products are protectant fungicides and as such thorough coverage is important and they need to be applied during the early stages of disease development to be effective. They do not kill, eradicate, an existing infection but do stop is spread,” Mr Cumming said.
 

Website: http://www.grdc.com.au

Published: March 2, 2015