Other families of predatory mites

• The Anystidae

All predators, they can be recognized by their large size (up to 3 mm), their reddish color, their disorderly but fast course and their general crab-shaped appearance. Sometimes present in fairly high densities in fruit crops, the best known species are Anystis spp. , especially Anystis agilis and A. baccarum. This last species, almost cosmopolitan, seems to be quite common everywhere. These predators are very voracious (a female of A. agilis can consume up to 875 females of T. urticae during her lifetime, at a rate of 22 to 40 prey per day) but their populations have a low demographic capacity. Very polyphagous, the Anystidae do not disdain plant exudates and other arthropods, such as thrips, cochineals or leafhoppers, on which their populations seem to multiply well. The Anystidae are all difficult to breed because they are very cannibalistic. Anystis baccarum is mentioned as a potential predator of thrips in South Africa. This species eliminates an infestation on blackberries and soybeans in 2 to 7 days with a predator / prey ratio of 1/30 and in 7 days on blackberries with an initial ratio of 1 / 50. These disadvantages, associated with their high sensitivity to plant protection products, turn them into auxiliaries whose effectiveness appears to be limited. They are seen on grapevine leaves, in spring as well as in summer, when temperatures are mild and humidity is high. They disappear very quickly afterwards.

• Bdellidae and Cunaxidae

Medium in size (600 µm), reddish, brown or greenish, common on the soil surface and sometimes on plants, bdelles and cunaxes are predators of various spider mites, T. urticae, Petrobia latens , Bryobia praetiosa , etc. Several cases of effective biological control against spider mites, springtails and mealybugs are mentioned in the literature. The eggs, deposited in the crevices of the bark, are the main stage of overwintering in temperate climates. Despite an often significant predatory activity, bdelles and cunaxes are polyphagous, ubiquitous and are not interesting candidates for biological control, especially on grapevines where they are rare. The two families are difficult to distinguish because they are close morphologically and taxonomically.

• Cheyletidae

Small in size (300 µm), characterized by slow movements, these mites are white, yellow or orange. Many are predators of spider mites, mealybugs and small insects, but some are parasites of birds, mammals or insects. Their populations have a low growth capacity compared to those of Phytoseiidae or Tetranychidae . They inject venom into their prey to paralyze them, which allows them to prey on large insects. Their poor search capacity for prey, a weak spatio-temporal coincidence with them, limited functional and numerical responses lead to the following conclusion: Cheyletidae do not have the potentialities necessary to keep spider mites below the economic tolerance threshold . However, like the Stigmaeidae, they are "second line" predators, thanks to their ability to survive in the absence of spider mites and their resistance to poor conditions. They are sometimes found in abandoned grapevines.

• Les Erythraeidae

These mites, whose larvae parasitize other arthropods, are large, reddish to brown. The most important and best known is species Balaustium putmani . It overwinters as eggs, hidden in crevices of all kinds, which hatch in the presence of free water. The larva is active and consumes spider mites and pollen. The 2 ^nd and 3 ^rd larvae are motionless, inactive, hidden in various shelters. The 2 ^nd larva and adults, on the other hand, are predators of the eggs and mobile stages of various arthropods (including lepidoptera and mealybugs). Very voracious (the 1 ^st larva consumes up to 20 eggs of P. ulmi , other larvae up to 5 times, the 250 to 350 eggs in 20 days female), these predators have only two generations per year . The average daily consumption of each female is 106 eggs or 25 females of P. ulmi . A female lays 175 eggs if she is fed eggs P. ulmi . The best hatching rate is obtained at 15 ± 2.5 ° C and development from larvae to adults takes 5-6 weeks. These mites attack various spider mites (species that weave a lot are not favorable), various predatory mites if they have no other prey, various insects (mealybugs, but not observed on grapevines), aphids, psyllids, lepidopteran eggs) ... and their congeners, if they have nothing else to eat. Many species are said to be pollinators. The mobile and active stages are sensitive to many pesticides, the hidden forms being much more resistant. These predators are not very capable of ensuring biological control on their own.

• The Stigmaeidae

They are green to yellow, ovoid or elongated, live in the soil or on plants and are generally predators of mites, the most important after Phytoseiidae. They fall into 2 important genera : Zetzellia and Agistemus and are very similar to spider mites. Very widespread in North America and Europe, lemon yellow in color, Zetzellia mali is a predator of eggs and immature stages of spider mites and tapeworms and all stages of various eriophyids in various fruit crops. This species overwinters under the scales of buds, bark, in crevices and at the base of trunks. It can survive without prey. Predator of other arthropods, sometimes phytophagous and polliniphagous, this species is considered as potentially usable in biological control in orchards but the results have never lived up to expectations. The Stigmaeidae participate in the control of spider mite outbreaks but cannot keep them alone below the economic threshold, due to their low multiplication capacity. Their greater persistence, in culture, their low dispersal, their low food requirements, their high survival capacity make them more specialized animals than the Phytoseiidae and undoubtedly complementary from the point of view of the regulatory activity of spider mite outbreaks. Very sensitive to pesticides, Stigmaeidae are nevertheless tolerant to many acaricides and fungicides and to some insecticides. They are found very occasionally and occasionally on the grapevine.

• The Trombidiidae

The Trombidiidae form a family of mites commonly of which many species are parasites or predators of arthropods, precious auxiliaries of crops, especially fruit trees including the grapevine, especially present in crops in spring.

The genera Trombidium and Allotrombium are the most diverse and the most common. They are large mites that can exceed 2 mm in size, generally vermilion to brick red in color and have silky cuticles.

Adults roam freely, looking for small animals (aphids, etc.) and insect eggs to devour. The larvae, on the other hand, seek a host to cling to, often an insect such as a locust or a diptera, but also hemiptera, arachnids such as mowers or spiders. They are spotted as small red blood cells on their hosts, feeding on their body fluid without causing fatal harm. When their prey is no longer enough for them or if these larvae have reached maturity, they let themselves fall. Some species are known to be voracious predators of insects and mites, but the identification and biology of the species are poorly understood.

• The Tydeidae

They are also small, fast mites, very ubiquitous, with reduced needle-shaped chelicerae, yellowish to greenish in color. They are often confused with the Phytoseiidae. These mites, present in the soil or on plants, feed at the expense of various natural foods: pollens, hemiptera honeydew, fungi, plant exudates, etc. They can be very abundant on grapevines. However, some species would feed, but in small quantities, on spider mite eggs or various stages of erophyids, but this role has not been clearly established in the case of viticulture. Homeopronematus anconai appears to feed on the various stages of the eriophyid agent of tomato bronzed mite, Aculops lycopersici. Other species have been reported as possible predators of erophyids or spider mite eggs, but this last point remains very controversial. Tideids are sometimes used as substitute prey for certain species of Phytoseiidae. Although the species concerned by each case may be different, the tideids would therefore play 3 different auxiliary roles: they consume certain pests, they serve as replacement prey for phytoseiids and they feed at the expense of sooty mold and other complexes of saprophytic fungi, which develop in particular on the honeydew of hemiptera. They are frequent on grapevines but we do not know at all the species present in France. Recent studies on the biology and behavior of certain species (in particular Tydeus caudatus and Tydeus californicus , two species present in Italy and which are undoubtedly part of our fauna) have shown that these mites preferentially feed at the expense of pollen and mycelium of fungi.