Mites enemies

Schausberger, R, Peneder, S., Jiirschik, S., Hoffmann, D. (2012) Mycorrhiza changes plant volatiles to attract spider mite enemies. Functional Ecology. 26,441. 

The first indication of the active role of plants in producing volatile chemicals to attract the natural enemies of their herbivorous attackers was found by Dicke, Sabelis, and coworkers (7, 24) in their studies of predatory mites that prey on plant-feeding mites. They found that when herbivorous spider mites feed on lima bean leaves, the plant releases a blend of volatiles that attracts predatory mites. The blend produced differs between plant species and varies depending on the species of spider mite that is attacking the plant. The blends even differ between plant cultivars infested with the same spider mite species, and the predatory mites can detect these differences (25,26). Artificially damaged leaves are not attractive to the predatory mites. 

We also found that the response of the plant to the caterpillar spit is systemic (31). Thus, not only the damaged leaves but the entire plant produces and releases volatile compounds when one or more leaves are attacked by caterpillars. Dicke et al. (7) had earlier found a similar effect in that undamaged leaves of a spider mite-injured plant attracted predatory mites. This systemic effect could be very significant in terms of enabling the natural enemies to locate their victims. It makes the plant under attack stand out from its neighbors and act as a beacon to foraging natural enemies. 

Red spider mite epidemics at periods of excessive dry weather in areas of heavy rainfall may be serious, but, so far, the duration of the invasions has been short in banana farms. Weather and natural enemies have, to date, quickly brought this pest under control. 

Plants respond to the mechanical or insect herbivore damage of their tissues." During herbivorous attacks, some plants emit a specific blend of volatiles, which may result in defense responses retarding development of the herbivores or attraction of herbivore enemies to feed upon them. In lima bean leaves, the spider mite-induced volatiles, as well as infestation and artificial wounding, activate the ethylene and JA signaling pathways. ... 

Organic growers also use biological control. They are allowed to import natural enemies of pests. This works either through predation or parasitism. This has proven effective for the control of red spider mite and specific caterpillars, and does not affect other insects. And a third technique is to use insect traps ranging from sticky yellow strips to pheromone or sexual lures. The pheromone traps use synthetic extracts of the chemical scents that... 

ANTHOCORID BUGS (anthocoridae). These include the genera Anthocoris and Orius. Whereas bugs of the Anthocoris genus, which are larger in size, are the most important enemies of the pear leafsucker, the smaller Orius species feed on spider mites. The Anthocoris hugs also feed on aphids. 

ENEMIES. Under natural conditions the red spider mite has very many enemies and should therefore not be a major problem in organic production. By far the most important enemy is the predatory mite, but globe beetles, green lacewings and the anthocorid bug Orius minutus can also provide valuable assistance. Depending on weather conditions, in some years these predators can achieve control of spider mites even without the aid of predatory mites. 

ENEMIES. The most important enemy of the apple rust mite is the predatory mite. But whereas control of red spider mite is achieved very quickly with the predatory mite, in the case of the apple rust mite it often takes 1-2 years longer to reach a stable situation. 

ENEMIES. No effective enemies of the pear leaf blister mite are known. 

Variability in induced plant volatiles complicates the reliance of natural enemies on these cues. One way of dealing with variability is through associative learning, which may allow parasitoids to learn which cues are most likely to lead them to suitable hosts at a particular time in a particular area. Moreover, recent studies suggest that plant volatile blends alone carry specific information on the herbivores by which they are attacked. For example, predatory mites can distinguish between the blends of apple trees infested by two herbivores species (20). Du et al. (21) showed that different aphid species elicit different volatile blends in bean plants and that the aphid parasitoid, Aphidius ervi, can use these differences to distinguish plants infested by its host. Aphis pisum from those infested by a nonhost. Aphis fabae... 

To summarize the resistance situation in broad terms, no key pest such as the codling moth, apple maggot, plum curculio has developed resistance to the OP azinphosmethyl, whereas a variety of secondary pests such as mites, aphid, leafhoppers, leafminers and their natural enemies have developed resistant strains thus azinphosmethyl has become more selective. The example cited later of management of cyhexatin resistance management in the spider mite... 

As we learn more about the biological world, we are finding that humble plants are often master chemists. For example, certain plants in the Amazon rain forests use chemistry in a very clever way to protect themselves. When attacked by herbivores such as spider mites or caterpillars, these plants produce and release compounds into the air that attract certain mites that are natural enemies of the attacking herbivores. These bodyguard mites assist the plant in fending off the attackers. 

In contrast to such strong insecticidal activity against lepidopterous insects, pyridalyl showed little insecticidal activity against species of Hemiptera, Coleop-tera and Orthoptera. Such selectivity of the compound is reasonably regarded as a preferable characteristic for uses in I PM programs, because some natural enemy insects are included in those families. In fact, pyridalyl showed minimal impacts on various beneficial arthropods such as parasitic wasps, predatory insects and mite and pollinators (Table 30.3.5) [1, 6, 7]. 

Helle, W. Sabelis, M. W. (1985) Spider Mites Their Biology, Natural Enemies and Control, Volume IB. 458p., Elsevier, Amsterdam... 

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