Earth mite hatching

There have been reports of earth mites emerging from oversummering eggs in some parts of Victoria and southern NSW. Agronomist, Geoff Pitson (Geoff Pitson Consulting), has reported earth mite hatchings near Cootamundra, in the South West Slopes of NSW. Low numbers of mites have been seen in an emerging oat crop, although Geoff says there were no signs of feeding damage. Researcher, Aston Arthur, has also observed earth mites in lucerne paddocks and some pastures in the North Central and Western districts of Victoria.  

Several species of earth mites occur in south-eastern Australia. They include redlegged earth mites, blue oat mites, bryobia and balaustium mites. They attack pastures and a variety of crops such as cereals, oliseeds, lupins and lucerne.  Some species 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.

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 use targeted rates of pesticide to control a particular pest and have then found that another unexpected pest is present that is not controlled by these sprays or seed dressings. For example, pesticide rates of many products used against redlegged earth mites are not effective against blue oat mites or balaustium mites.