Peanut mites love a dry season
Peanut mites (Paraplonobia spp) only attack peanut crops and are generally only a problem in dry conditions. They are tiny arachnids that can cause significant damage when present in large numbers.
Both adults and nymphs feed on the peanut leaves, piercing and sucking the leaf cell contents. This causes mottling and discolouration (silvering) of the leaves and can result in dropping of lower leaves, yield loss, and even plant death, if the infestation is heavy.
Adults are dark green to black with 8 pale-coloured legs. Adults are 0.5 mm long. Nymphs are smaller but similar in appearance.
Damage is most severe in dry conditions and numbers tend to reduce greatly after rain (or irrigation). Only treat crops for mites if no rain is forecast. Crops often outgrow the damage.
Peanut mites are very mobile and will jump off the underside of leaves if disturbed. To monitor their presence, collect leaves and inspect for silvering on the underside.
They are similar to two-spotted mite and bean spider mite, but peanut mite is much larger than either of these other species.
Predators of mites include small predatory bugs, thrips, lacewings and ladybirds.