Blue Oat Mites

Blue oat mites are active in many regions after hatching from over-summering eggs. Consultant agronomist, Glenn Sheppard (IMAG Consulting), has found blue oat mites near Dubbo, in the Central West Slopes and Plains district of New South Wales. Glenn says the mites observed are quite small, which suggests they have only recently hatched. Mites have not been observed causing feeding damage to emerging crops in the area.

Agronomist, Warwick Nightingale (Delta Agribusiness), reports finding small blue oat mites in a seedling canola paddock east of Lockhart, in the Riverina district of New South Wales. In Victoria, blue oat mites have been observed across the Western and North Central districts. Agronomist, Brad Jackson (Tyler's Hardware & Rural Supplies), has reported seeing blue oat mites at Rupanyup, in the Wimmera district of Victoria. Blue oat mites are also likely to have now hatched and begun building up in numbers in the Northeast and Gippsland districts of Victoria, and the Central and Southern Tablelands districts of New South Wales.

Blue oat mites (Penthaleus spp.) attack emerging pastures, canola and cereal crops. Plants will often outgrow mite-feeding damage when the growing conditions are favourable. If chemical control is warranted, blue oat mites should be targeted within 2-3 weeks of emergence. This approach should protect newly germinated seedlings, which are most prone to mite attack. Insecticide seed treatments will also offer some (but not complete) protection to emerging crops, however growers are encouraged to monitor paddocks over the next month. Weed control will suppress the build-up of blue oat mites during the growing season.

Blue oat mites can be distinguished from other mites by their blue-black coloured body and characteristic red mark on their back. They are often mistaken for redlegged earth mites due to their similar appearance and sympatric life cycle. However, blue oat mites and redlegged earth mites differ markedly in their biology and tolerance to pesticides, thus require separate management strategies. Blue oat mites are the most abundant earth mites in many cropping and pastoral areas of Victoria, Tasmania and New South Wales. For assistance with identification download the GRDC Back Pocket Guide - Crop Mites.