Strategies for control of the redlegged earth mite in Australia

The redlegged earth mite, Halotydeus destructor, continues to be an intractable pest causing damage to most crop and pasture species in southernAustralia.H. destructor feed on all stages of plants, but particularly damage seedlings in autumn. Research has aimed to develop new controls based on a better understanding of the biology and ecology of this pest. Chemicals remain the key tool to controlH. destructor, despite the recent appearance of resistance to synthetic pyrethroids. A control package, Timerite, has been developed bywhich a singlewell-timed spray in spring can preventH. destructor from developing diapause eggs. Field trials show this strategy provides effective control of H. destructor the following autumn, andprotects plant seedlings, althoughmite populations buildup againduringwinter.Non-chemical control strategies include grazing, the use of tolerant plants such as cereals, resistant legume cultivars and avoiding rotations where favourable host plants are available in theyear beforegrowing susceptible crops suchas canola.Natural enemies canassist inmite control, and their numbers can be enhanced by methods including increasing landscape features like shelterbelts. Interspecific competition can occur between H. destructor and other pest mites, but the extent to which these interactions influence the structure of pest communities under different management regimes remains to be investigated.