Redlegged earth mites

Redlegged earth mites (Halotydeus destructor - RLEM) were prevalent earlier in the year, with population sizes in autumn and early winter considerably larger than observed for many years. Early spring is the ideal time to think about potential issues for next season. For RLEM, control can be timed to occur during a short window in spring when mites have ceased laying winter eggs (eggs that must hatch this season) and before they start laying diapause eggs (over-summering eggs that survive until next season). This approach, known as Timerite^®, can significantly reduce RLEM numbers the following autumn.

The optimum ‘spring-spray’ dates for RLEM in eastern Australia are mostly between mid-September and mid-October, and are freely available from the Timerite^® website. Some examples of the recommended dates are: Horsham - 23^rd Sept, Bendigo - 28^th Sept, Wagga Wagga - 29^th Sept, Dubbo - 14^th Oct, and Colac - 16^th Oct. The date is based on geographical location and is therefore unique to each property. It is recommended that spraying be carried out within the two-week period before the optimal date.

Correct identification of mites before deciding to spray is important. Timerite^® is designed to only control RLEM; it will not effectively control other pests, such as blue oat mites. Before using this approach, consideration should also be given to the actual number of mites present and the susceptibility of the crop to be sown next season. Insecticides need to be used carefully to avoid resistance issues, which have already emerged in RLEM.

In pastures, RLEM numbers can also be reduced through careful grazing management. Field trials in Western Australia have shown that pastures grazed to 1.4t/ha FOO (Food on Offer) during spring will have significantly lower levels of mites, equivalent to numbers after spraying pastures with high FOO levels.