Balaustium mites

Agronomist, Nathan Stoll (Mangoplah Farm Centre), reports finding high numbers of balaustium mites (Balaustium spp.) in a newly sown clover pasture paddock just southwest of Wagga Wagga, in the South West Slopes district of New South Wales. The mites were found to persist after an application of omethoate at 200 ml/ha. Nathan says the level of damage was moderate in some patches and that a second chemical application was required.

Balaustium mites are often confused with other mite pests. Adults grow to be twice the size of a redlegged earth mite, about 2 mm in length. They have a rounded red-brown coloured body, densely covered with stout hairs, with eight orange-red coloured legs. Balaustium mites have recently been identified as emerging pests within the Australian agricultural industry. The damage caused by these mites in Australia seems to have significantly increased in the last decade, with reports indicating that they can cause extensive damage to cereal, canola and lupin crops. Crops sown into paddocks with a pasture history and high levels of broad-leaved weeds, especially capeweed, are likely to be most at risk from balaustium mites.

Balaustium mites are often reported to persist in the field following chemical applications. Recent pesticide bioassays conducted by cesar have shown balaustium mites are more tolerant to a range of organophosphates and synthetic pyrethroids compared with other mites. Moreover, there are currently no insecticides registered for the control of balaustium mites in Australia. In cropping situations where several pests have been present, reports indicate that high rates of synthetic pyrethroids aimed at other pest species have provided adequate control of balaustium mites.

Click here for images of balaustium mites and refer to PestFacts Issue No. 6 for more information.