Bulb mites—Rhizoglyphus and Tyrophagus spp.
Bulb mites are shiny, creamy white, bulbous mites that range
in size from 0.5 to 1 mm long. They have four pairs of
short brown legs and look like tiny pearls with legs. They
generally occur in clusters, inhabiting damaged areas under
the root plate of onion bulbs or garlic cloves.
Bulb mites damage bulbs by penetrating the outer layer of tissue and allowing rotting organisms to gain
entry. Plant growth may be reduced and bulbs may rot in storage. On seeded onions, mites can cut off the
radicle before the plant becomes established.
Rapid crop rotation fosters the survival of mites on leftover vegetation. After harvest, clear all vegetation
to allow organic matter to decompose; this reduces populations of the mite. Flood irrigation or heavy
rains during the winter may reduce mite levels in the soil.