Mites are small, often hard to see, arachnids that can have different colors, including red, green and brown. They are found on the undersides of leaves and like warm, dry environments. In fall and winter, they can turn orange-red.
Mites are common pests of plants. They are usually less than a millimeter in size, making them unnoticeable. They feed on plant sap, which leads to leaf death and causes reduced yield of the affected crop. These tiny mites are found worldwide:
- European red mite (Panonychus ulmi) – these originally European small mites are found on a variety of plant species. Adult females are red and about 0.35 mm in size; males are somewhat smaller and yellow in color. The eggs are red and about 0.20 mm in size.
- Southern Red Mite (SRM) (Oligonychus ilicis) – despite its name, this mite is found all over the world. Female southern red mites measure about 0.38 mm and males 0.3 mm. Southern red mites are red in color, as are the minute eggs.
- Spruce spider mite (Oligonychus ununguis) – these minute (+ 0.3 mm) mites are usually dark colored, have yellowish legs and red eyes. The spruce spider mite is mostly found in somewhat colder regions.
- Red spider mite (Tetranychus urticae), also called Two-spotted spider mite – is widespread in temperate and subtropical regions. The red spider mite has various colors: red, brown, green and yellow. The mites are about 0.5 mm in size.
Control
Spray with an Insecticidal soap or with pyrethrum (house plants).
Control with the predatory mite (Phytoseiulus persimilis) is mainly used in professional (greenhouse) cultivation.
Prevention
Predatory mites and ladybirds are the natural enemies; in professional horticulture they are also used for control. In particular, the predatory mite Amblyseius californicus is effective in controlling all growth stages of mites.
