Balaustium mites

Balaustium mites make a late appearance around the southern Wimmera in Victoria

Balaustium mite, revealing a dense covering of stout hairs (Source: cesar)

 

Where have they been reported?

Two cereal crops (oats and barley) in the Victorian Wimmera have recently experienced moderate levels of Balaustium mites (Balaustium medicagoense). One crop was located near Stawell and the other near Elmhurst, approximately 50kms apart. Both crops were in the seedling (1-3 leaf) stage and had recently come out of long-term pasture. Whilst not causing major damage, the Balaustium mites were reducing seedling vigour to some extent, and in one case, an insecticide spray was deemed necessary to protect the crop.

About Balaustium mites

Balaustium mites are often confused with other mite pests. Adults reach about 2 mm long, which is twice the size of redlegged earth mites. They have a rounded, red-brown coloured body, densely covered with stout hairs, and eight orange-red legs. Leaf damage symptoms can also help to identify different mite species. Balaustium mites cause less patchy silvering of plant cotyledons and leaves than that of redlegged earth mites and blue oat mites; in canola, they cause distinctive cupping and leathering of cotyledons. Click here for images of Balaustium mites.

For detailed information on Balaustium mites, including their occurrence, lifecycle, behaviour, damage symptoms and management strategies, go to Balaustium mite within the new PestNote series.

Our advice

Balaustium mites are difficult to control with insecticides and will typically persist in the field following chemical applications aimed at other mite species. Recent findings by cesar show Balaustium mites are more tolerant to most organophosphate and synthetic pyrethroid chemicals registered for other mites. It is therefore important to correctly identify mite species and seriously consider non-chemical control methods for these mites. Reports indicate that crops sown into paddocks with a pasture history and high levels of broad-leaved weeds, especially capeweed, will be most at risk from mite damage.

Presently, Pyrinex^® Super is the only registered product to control Balaustium mites in broadacre and is only registered in canola crops.

 

Sources of field reports of Balaustium mites

Josh Douglas – Researcher, The University of Melbourne

Ben Cordes – Agronomist, Tylers Hardware & Rural Supplies (Victorian Wimmera)