Southern NSW growers are being advised to monitor for red-legged earth mites this winter, with experts warning environmental conditions have been ideal for mass hatchings, potentially putting emerging winter crops at risk.
University of Melbourne’s Garry McDonald said rain in some southern regions followed by cooler conditions in May had been conducive to population increases of the pest, which could affect canola, lupins, cereals and legume seedlings, as well as pastures.
‘‘Red-legged earth mites, or Halotydeus destructor, only hatch in autumn under specific conditions, like those we had in May when areas received at least 5mm of rain accumulated over five consecutive days or less, followed by 10 days of average daily temperatures below 16°C,’’ Dr McDonald said.
‘‘Our predictive modelling suggests the peak egg hatch would have occurred in mid-May in areas like Wagga Wagga and Albury.
‘‘But as most growers would be aware, the juvenile mites are microscopic so we wouldn’t expect them to have noticed much RLEM activity until early to mid-June.
‘‘So the time to monitor crops, and where necessary enact management strategies for RLEM, is now.’’
Red-legged earth mites are traditionally active from autumn until mid-spring across southern NSW, with pest hatching often coinciding with crop emergence.
An insecticide resistance management strategy has recently been developed for the pest, which growers and advisers are encouraged to become familiar with.
■The strategy is available at: https://ipmguidelinesforgrains.com. au/ipm-information/resistance-management-strategies/