Cheletogenes ornatus (Canestrini & Fanzago)
Taxonomic placing: Acari, Prostigmata, Cheyletidae.
Morphology: The reddish body of the female is about 0.3 mm long, with 2 pairs of eyes. Dorsum covered by 2 reticulated plates. Propodosomal plate with 7 pairs of setae, median plate with 2 pairs of setae. All dorsal setae shell-like. Leg I without claws or empodia. Gnathosoma prominent with a strong thumb claw complex; the palpal tarsus with sickle-like and/or comb-like sensilli.
Distribution: Apparently cosmopolitan.
Life history: Development of a generation requires several weeks and only 2-3 generations are raised annually. The mite feeds by sucking on the eggs or the body contents of mites or scale insects. Fecundity, usually less than 20 eggs/female, depends on the prey; more eggs are laid when feeding on mites (such as Cenopalpus pulcher) than when scale insects (such as Parlatoria oleae) are the prey. This slow-moving predator often inhabits fruit trees and ornamental plants. It hides in protected sites, such as the shields of scale insects or tree buds, and ambushes passing mites or scale insect crawlers. It can survive for several weeks without food, and cannot subsist on pollen alone. Males are usually present, but in North America the mite is thelytokous.
Economic importance: A common predator that feeds on the crawlers of several scale insect pests, like Parlatoria blanchardi, and may significantly reduce their populations in Egypt. Other major prey include the pests Chrysomphalus aonidum, Parlatoria oleae and Russellaspis pustulans. Other pest prey include mites, such as Brevipalpus obovatus, C. pulcher, and Raoiella indica.
Effect of pesticides: Organophosphates were the least harmful to females of C. ornatus, whereas chlorobenzilate was highly toxic.
References
Atwa, W.A., El-Naggar, M.E., Khalil, A.M., El-Shaer, M.E. and Mostafa, Z.M.M. 2018. Biological studies on Cheyletid predator mite, Cheletogenes ornatus (Canestrini & Fanzago) when fed on the different preys. Egyptian Academic Journal of Biological Sciences A. 11: 21-29.
Avidov, Z., Blumberg, D. and Gerson, U. 1968. Cheletogenes ornatus [Acarina: Cheyletidae], a predator of the chaff scale on citrus in Israel. Israel Journal of Entomology 3: 77–93.
Mesbah, A.E. and Omar, N.A. 2014. Predator-prey preferences and life-table-parameters of Cheletogenes ornatus (Canestrini & Fanzago) to red palm mite Raoiella indica Hirst and date scale-Insect Parlatoria blanchardii (Targ.). Acarines 8:19-23.
Moraes, G.J.D., Neto, R.S. and Pinto, H.C.S.1989. Morphology, biology and pesticide tolerance of Chelotogenes ornatus (Acari: Cheyletidae). Entomophaga 34: 477-484.
Rezk, H.A. and Gadelhak, G.G. 1996. Relationship between phytophagous and predatory mites in citrus orchards and the effect of acaricides on their populations. Alexandria Journal of Agricultural Research 41:217-224.
Zaher, M.A. and Soliman, Z.R.1971. Life history of the predator mite, Cheletogenes ornatus (Canestrini and Fanzago). Bulletin de la Societe Entomologique d’Egypte 55: 85-89.
Zaher, M. A., Yousef, A.E.A. and Kandil, M.M. 1981. Effect of food on the biology of Cheletogenes ornatus (C. & F.) (Acari: Prostigmata: Cheyletidae). Acarologia 22: 361–366.
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