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Hello dear community of 
, 
, today in THEME WEEK - FARM PESTS: Mites.
Name:
Acari or Acarina (from the Greek ακαρής akarés, "diminuto", "that does not cut"), commonly denominated as mites, are a subclass of arachnids, 1 although for a long time they were considered an order. There are almost 50,000 species described, and it is estimated that there are between 100,000 and 500,000 species that have not yet been found.
characteristics:
The mites are small, with hexapod larvae (six-legged), and three eight-legged nymphal stages (the cycle is abbreviated in derived groups).
The body is divided into two tagmas or regions. The anterior region, called gnathoma in the parasitiform mites and proterosome in the acariformes, is small and is later delimited by a suture.
The posterior tagma, known as idiosome (parasitiformes) or hysterosoma (acariformes), carries the legs and has lost all external trace of segmentation.
The chelicerae are important in the capture and ingestion of food.
The pedipalps consist of one to six segments. They serve to locate and manipulate food and therefore are endowed with mechanoreceptors and chemoreceptors.
The main mites that are considered agricultural pests:
You can find mainly two types: eriophids and tetraniquids:
Eriophids:
They are pests of permanent plants.
They have sexual reproduction, a size of about 0.1-0.2 mm, they are whitish in color, they eat with five very small stilettos and inject saliva, but the mechanical damage is very small, the saliva can carry viruses. They need living tissue to live, never on dead tissue. .
Tetranichids:
They are the most characteristic mites, with chelicerae through which they feed, and palps that are sensory organs. They present four pairs of legs. They are suckers, the size is about 0.5 mm, the damage they produce is basically the emptying of the cellular content. Yellowish pits are usually observed in most cases. In the case of cotton, the spots may be violet in color. The reproduction is sexual, they pass through two stages of larva and another of nymph. Combat with Tetradifon + Dicofol, Fembutestan. They are usually located on the underside of the leaves.
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species are mainly differentiated:
They have a size of about 0.5 mm. It attacks more than 150 species of agricultural interest, both herbaceous and woody. It is located mainly on the underside of the leaves and forms abundant cobweb. The eggs are totally spherical. They go through two states of larva and another of nymph. When they feed on the leaves, they cause discoloration and drying, which in most cases manifests itself with yellowish spots and / or bulges in the beam. They can produce intense and sudden defoliation, especially in summer.
The seasonal evolution of the population abundance in specific plots is quite irregular, being able to take place attacks to the crop from May to November.
Panonychus ulmi or red fruit mite:
The Red Spider devastates entire crops in a few days. Many farmers fear this terrible plague. When the heat arrives, they desperately seek to combat these red spiders. All kinds of media are used as chemical insecticides and acaricides.
The red spider affects a large number of crops of economic importance, such as horticultural crops, extensive crops (tomatoes, corn, cotton), citrus fruits, grapes, fruit trees and also ornamental plants. It is capable of devastating a plantation in a short time, due to its high reproductive potential, its short life cycle, its high rate of development and its rapid dispersal capacity.
This mite can present morphological characteristics of different nature, its color above all, which can vary in response to its diet, host plant, environmental factors and development status.
Types of crops that affect these pests:
HORTICULTURAL: Appears between flowering and fruit set. They feed on the leaves, and spots and yellow spots on the leaves are observed.
CORN AND SOYBEAN: At the beginning there are foci, where the leaves acquire a lighter color.
CITRUS: They eat the leaves and fruits.
VINEYARD: Causes significant damage to table grapes and especially during sprouting
ORNAMENTAL: The leaves are yellowing as the mites suck the intracellular fluid until they finally dry.
Control of the plague of mites in agriculture:
Prevention measures:
Sowing fescue between lines increases the level of phytoseiids and decreases the presence of spider on trees. In addition if pollen is allowed to be used by phytoseiids as food.
It is recommended to perform treatments only when the percentage of occupied rings exceeds 54% and the percentage of leaves
Symptoms occupied by T. urticae exceed 22%.
Biological media:
There are no known effective natural enemies against the red spider in citrus, although phytoseiid mites Neoseiulus californicus and Phytoseiulus persimilis and larvae and adults of the coccinellid coleoptera Stethorus punctillum are frequently seen among their colonies.
Conclusion:
The mites are one of the pests that gives most headaches to farmers because of the damage they cause to their crops, therefore the problem must be detected and act with the relevant measures for the treatment of this pest that leads to the destruction of the different crops where they have colonized.
