Eriophyoid mites (erios for short) are the smallest of all mites, with adults around 0.5 mm long. Their small size makes it difficult to spot them in the field, even with a good hand lens. They are sporadic pests that cause serious damage during outbreaks. Usually, erios are found because of the symptoms they cause – bud deformation, rusting or galling, depending on the species. Some erio species live on plants without causing symptoms at all.
If you do see them (usually with the help of a microscope), they are unmistakable: they look like miniature worms with tiny legs at the front end. All erios are plant-feeding and very much host-specific. Some are serious crop pests. Because they are so tiny, many species (especially those that don’t cause symptoms) are undiscovered. Currently there are over 4 865 species known world-wide, around 250 in SA, with more being discovered every day. In fact, the Agricultural Research Council (ARC) has officially listed 25 as pests in SA. Let’s look at just a few of the more common ones.
Davina Saccaggi, Elleunorah Allsopp, Nompumelelo Ngubane-Ndhlovu and Edward Ueckermann
(CRI, ARC Infruitec-Neitvoorbij, DALRRD, North-West University)