There are several types of mites that can cause damage to the foliage of orchids, the most common being the spider mites. (See: Red Spider Mite)

The "Mites" are arachnids, related to ticks and spiders and are very small, have 8 legs and may be brown, red, green or cream in color. Mites live in colonies, mostly on the underside of leaves. Because of their size, they are not easily noticeable and the "Paper" test is the best way to find them. Place a A4 size, white paper, under the infested leaf and gently shake up the leaf. The mites, if present, will be dislodged and fall onto the paper. You will then notice them as tiny moving specks.

Females deposit red to creamy colored eggs on leaves or in then netting they produce. The Juveniles resemble adults but have only six legs.

Mites cause a lot of damage by sucking the cell content from leaf tissue and that can cause the premature loss of leaves. Mites reproduce rapidly in hot and dry weather and under favorable conditions a generation can be completed in a week. Wind currents can disperse them to other plants many meters away.

Control: Mites have many natural enemies like: The black ladybird beetle, the lacewing larvae, some thrips species, the pirate bugs and other predatory mites. These naturally occurring enemies may not eradicate mite populations and the use of miticides or pesticides may become necessary. Use pesticides to spray only plants infested; this will help protecting the natural enemies.

Mites flourish on orchid plants that are under stress and dislike water. In other words, mites avoid well watered and fertilized plants. Spraying plants with water can reduce mite populations as water washes the mites off.

Horticultural oils applied every week, provide good mite control. Miticide applications are sometimes needed. Alternate the use of miticides with other types of pesticides. Read the label first. Make sure whatever you use kills mites.