A recent social media post of mine about redlegged earth mite got lots of comments so I thought I should write a longer piece about the pest.
The first thing to know about the redlegged earth mite (Halotydeus destructor) is that it is an introduced pest from southern Africa. It is now a pest of southern Australia. It’s also really small – about 1mm long – with a round, velvety black body and eight red legs. Here is a close-up image.
The second thing you need to know about this pest is that it mostly attacks broadleaf plants including clovers in lawns, and seedlings of a wide range of vegetables and ornamentals. It also feeds on and breeds in a number of broadleaf weed species.
Now let’s join the dots between the ‘first thing’ and the ‘second thing’. One of the weeds it likes to breed in is capeweed (Arctotheca calendula) which is an introduced weed from South Africa – the same region the redlegged earth mite originates from!
This is capeweed.
The next thing you need to know is what redlegged earth mite damage looks like. Earth mites are sapsuckers, and produce a characteristic silver or white pattern on leaves where they feed. When large numbers of mites attack a plant the leaf tips may shrivel and die. Seedlings are particularly vulnerable, and may die.
This is what redlegged earth mite damage to clover looks like…
and to pea seedlings ….
and silverbeet! Halotydeus destructor – what an appropriate scientific name!
You also need to know about their life cycle. Redlegged earth mites are active over the cooler months from May to November. They hatch in autumn from over-summering eggs held in the bodies of dead females on the soil surface. Eggs hatch and follow a classic mite life cycle – larva, protonymph, deutonymph to adult. There are about three generations over the cooler months, each lasting about eight weeks. When temperatures increase and host plants dry off in spring, female mites die with about 100 over-summering eggs held in their desiccated bodies!
What can we do to prevent them damaging our plants? The best preventative method is weed control. Remove all broadleaf weeds near where susceptible seedlings grow. You could try placing plastic sleeves made from plastic drink bottles around seedlings. Smear vaseline (or some other sticky substance) around the rim to prevent mites climbing in. This will work (against mites and other seedling pests) but it may look unsightly (to some people).
No pesticides are specifically registered for use against redlegged earth mites in home gardens, but there are several with a general registration against ‘mites’. My preference is horticultural oil (e.g. EcoPest Oil, PestOil, etc.) or soap (e.g. NatraSoap) sprays, or perhaps you could try neem (e.g. Eco-Neem).
If you combine one of these products with weed control you will win the battle. If you are looking for a quick fix they will win!
I’ll leave you with an image that I just snapped on my phone. These pea seedlings have not been sprayed. They are growing in an area where I always control weeds – there is not a redlegged earth mite to be seen. I think the nice fresh mulch might help too.
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