Agistemus exsertus Gonzalez
Taxonomic placing: Acari, Prostigmata, Raphignathoidea, Stigmaeidae.
Distribution: North Africa, Middle East, North America and China.
Morphology: Reddish body of female about 0.4-0.5 mm long, dorsum covered by 3 unreticulated plates. Propodosomal plate with 3 pairs of setae, median plate with 5 pairs of setae, and 2 pairs on the suranal plate. Postocular bodies very large.
Host plants: Many, including apple, citrus, cotton, tea and others.
Life history: Agistemus exsertus feeds on the eggs and other stages of eriophyids, spider mites, some stored food Acaridae, scale insects, whiteflies and pollen. A female may daily consume 60 eggs and 45 immature and mature stages of Aculops lycopersici. It can also be reared on the eggs of Ephestia kuehniella, Parlatoria ziziphi or Tyrolichus casei Oudemans (Acaridae). It prefers eggs over other stages and its fecundity when feeding only on eggs may reach 80 or more eggs/female. Development at 28-30°C lasted about 1 week and longevity came to ca 4 weeks; about 420 day degrees were required to complete a generation. Each female may consume several hundred eggs, their voracity and longevity depending on the prey. The mite can be mass-reared on an exclusive diet of date palm or citrus pollen. The fecundity of A. exsertus is strongly affected by the leaves on which it lives. Mites on slightly hairy leaves (e.g. mulberry (Morus alba L.)) were most fecund, whereas those on rough, pubescent leaves (e.g. apple) were the least fecund.
Economic importance: Agistemus exsertus is a predator of the eggs and other stages of various eriophyids and spider mites that infest apple, citrus, some vegetables, ornamentals and various field crops. It may help in controlling these pests when or before (in spring) other predators occur. It successfully controlled Panonychus citri in a greenhouse.
El-Badry, E.A., Abou-Elghar, M.R., Hassan, S.M. and Elkilany, S.M. 1969. Life history studies on the predatory mite Agistemus exsertus. Annals of the Entomological Society of America 62: 649-651
Elbadry, E.A., Abo Elghar, M.R., Hassan, M.S. and Kilany, M. 1969. Agistemus exsertus as a predator of two tetranychid mites. Annals of the Entomological Society of America 62: 660–661.
Momen, F M. 2001. Effects of diet on the biology and life tables of the predacious mite Agistemus exsertus (Acari: Stigmaeidae). Acta Phytopathologica et Entomologica Hungarica 36: 173–178.
Osman, A. A. and Zaki, A. M. 1986. Studies on the predation efficiency of Agistemus exsertus Gonzalez (Acarina) on the eriophyid mite Aculops lycopersici (Massee). Anzeiger für Schaedlingskunde, Pflanzenschutz, Umweltschutz 59: 135-136.
Rasmy, A.H. 1975. Eine Methode zur Massenzacht der Raubmilbe Agistemus exsertus Gonz. (Acarina: Stigmaeidae). Anzeiger für Schaedlingskunde, Pflanzenschutz, Umweltschutz 48: 55-56.
Rasmy, A.H., Osman, M.A. and Abou-Elella, G.M. 2011. Temperature influence on biology, thermal requirement and life table of the predatory mites Agistemus exsertus Gonzalez and Phytoseius plumifer (Can. & Fanz.) reared on Tetranychus urticae Koch. Archives of Phytopathology and Plant Protection 44: 85-96.
Rehamn, M.U., Kamran, M. and Alatawi, F.J. 2018. Genus Agistemus Summers (Acari: Trombidiformes: Stigmaeidae) from Saudi Arabia and a key to the world species. Systematic and Applied Acarology 23: 1051-1072.
Saber, S.A. and Rasmy, A.H. 2010. Influence of plant leaf surface on the development, reproduction and life table parameters of the predacious mite, Agistemus exsertus Gonzalez (Acari: Stigmaeidae). Crop Protection 29: 789-792.
Wafa, A.K., Zaher, M.A., Afifi, A. and Gomaa, E.A.1969. Effect of diet on development of the predacious mite Agistemus exsertus. Zeitschrift für Angewandte Entomologie 63: 382-388.
Yue, B. and Tsai, J.T. 1995. Agistemus exsertus Gonzalez (Acari: Stigmaeidae) as a predator of citrus red mite (Panonychus citri McGregor)). Journal of the New York Entomological Society 103: 107-113.