Redlegged earth mites

There have been several reports of redlegged earth mites emerging post-diapause in the cooler wetter regions of Victoria and southern NSW. Vicky French (Elders) says redlegged earth mites have been found in some pastures in the Western district of Victoria, mainly attacking clover. Redlegged earth mites are perhaps the most important invertebrate pest species in Australian agriculture. They attack a variety of crops and pastures, including cereals, oilseeds, legumes and fodder crops. Redlegged earth mites can also survive on a variety of weeds, particularly broad-leaved weeds. For this reason, management of weeds can play an important role in reducing the build up of mite populations within crops. For information on redlegged earth mites in pulses click here.

Jan Edwards (DPI, NSW) has reported signs of earth mite damage around parts of the southern Tablelands of NSW, while John Sykes (John Sykes Rural Consulting) has reported sporadic mite problems in the South West Slopes district. At this stage, mites have been relatively confined to pastures, although with many crops recently sown and a number already emerging, crops will need to be monitored closely. John says seed treated canola, which is now commonly sown, seems to have provided good early protection. Cam Nicholson (Southern Farming Systems) has observed earth mites, predominantly in pasture, around the Geelong district. Cam says the damage to pastures caused by emerging redlegged earth mites this season, may be negated by the vigorous plant growth that has occurred due to the good autumn rains and weather conditions.

It is important to monitor mite numbers at this time of the year because emerging seedlings are particularly vulnerable to attack. Examine plants for damage and search for mites on leaves and on the soil surface. There are a variety of chemicals registered for earth mites, which if used within 2-3 weeks of emergence can drastically reduce mite populations. However, if numbers are low enough and favourable growing conditions occur, crops can often out-grow the mite damage without necessitating sprays.

Before deciding on the most appropriate control measure, ensure the correct mite species has been identified. Problems can occur when growers have targeted rates of pesticide to control a particular pest and then found that another unexpected pest is present that is not controlled by their sprays or seed dressings. For example pesticide rates of many products used against redlegged earth mite are not effective against blue oat mites or balaustium mites.