Root and onion mites can only be found by taking the plant out of the ground and looking through a microscope.These include several different types of ticks, which are united by the fact that they damage the underground parts of plants. Among root mites, root mites of the genus Rhizoglyphus and bulbous mites of the genus Steneotarsonemus are more common.
These ticks harm not only bulbous plants (amaryllis, hyacinths, tulips), but also other flowers, for example, orchids, cacti. Root mites are usually very small in size from about 0.5 to 1.5 mm, a wide oval body of light yellow, gray or brown. Outwardly, they are in the form of a translucent ball, with tiny, hair-like legs. Eggs in ticks are broadly oval, large, whitish or gray. Usually eggs are laid in the ground, but some species of root mites make clutches near the surface of the earth - in the axils of the lower leaves, near the bulbs of orchids, in the neck of the bulbs.
Root mites gnaw through the tissues of the bulbs, laying eggs there in huge quantities - about 300 eggs from one female bulb or root mite. At the same time, at the initial stage of the lesion, the eaten out places and moves of the ticks are visible, however, gradually the ticks eat up the entire bulb. The damaged onion falls apart in the hands, all internal tissues are eaten out in it, only white dust remains, and clusters of ticks are visible to the naked eye.
Signs of damage to the onion and root mite - the appearance of red or brown spots on the bulbs, the formation of white dust, similar to semolina. Outwardly, plants stop growing, then yellowing of leaves begins, deformation of peduncles and leaves, sometimes probed and dry areas appear. The plant will eventually die.
Root mites actively multiply and develop in a wide temperature range, optimally from 10 to 26 ° C and even higher, when conditions change, they do not die, but fall into a state of diapause. The development of root mites is facilitated by high humidity of 60-65%. Therefore, one of the measures to prevent the appearance of bulbous and root mites is proper storage. Tubers, bulbs, root vegetables are stored in a dry cool room, with humidity not higher than 30%.
Root mite control measures
Carefully examine the bulbs before planting. Affected bulbs and plant roots are kept in acaricide solution - you can use neoron, actellic, carbofos, apollo, with full immersion in the solution for 20-30 minutes. Borneo (the active ingredient etoxazole), a hormonal acaricide against eggs and larvae, has shown very high efficacy, but it does not affect adults, i.e. it must be combined with other acaricides.
Preparations with the active ingredient spiromesifene (Oberon) also help well - a very wide range of pests - many types of ticks, destroys all forms of the pest - eggs, larvae, adult ticks.
When buying bulbs, pay attention to integrity - infected bulbs with spots, dry, brown areas of scales, and only with severe infection in places are squeezed under the fingers. Ticks hide under one or two upper sheets of onion scales, you can see them with a magnifying glass. Before planting, the bulbs can be soaked in acaricide solution for a few minutes, and then dried before planting.