Scymnus
Taxonomic placing: Insecta, Holometabola, Coleoptera, Coccinellidae.
(Some species were placed in the genera Nephus or Stethorus)
Geographical distribution: World-wide; some species were introduced into other regions for biological control purposes.
Morphology: The adult body is elongate-oval, somewhat convex, 1-3 mm long, elytra black to brown, sometimes with red spots and closly setose. The transverse head partially covered by the pronotum and the thorax may be red-brown, like the legs. The larvae are covered with waxy filaments or outgrowths, somewhat similar to those on mealybugs, which may protect them from ants.
Life history: Both larvae and adults are predators, preying mostly on aphids and also on spider mites, coccoids, whiteflies and on insect eggs. The threshold of development is around 11°-12°C, about 300 day degrees are needed to raise a generation, which can be complete in about 1 months. Several generations may annually be completed and they deposit around 30 eggs/female. Adults can survive for another 3-4 weeks. The activity of Scymnus may be affected by the prey’s host plants, as S. punctillum was most active on pepper and tomato and least on aubergine.
Economic importance: Several species of Scymnus reduce the populations and often control pestiferous aphids, spider mites, whiteflies and coccoids worldwide. They may be the most abundant predators in agroecosystems where aphids are major pests. Several species, like S. punctillum, are in commerce and were introduced to various regions for aphid and mite control.
Some Middle Eastern species of Scymnus that prey on aphids, unless otherwise noted.
Scymnus apetzi Mulsant.
Scymnus flavicollis Redtenbacher.
Scymnus hiekei Fürsch.
Scymnus interruptus Goeze (preys on mealybugs).
Scymnus levaillanti Mulsant.
Scymnus pallidivestis Mulsant (preys on whiteflies).
Scymnus punctillum (Weise) (preys on spider mites).
Scymnus subvillosus (Goeze).
Scymnus suturalis Thunberg.
Scymnus syriacus Marseul.
References
Allawi, T.F. 2006. Biological and ecological studies on Scymnus syriacus and Scymnus levaillanti (Coleoptera: Coccinellidae). European Journal of Entomology 103: 501-503.
Aslan, M.M. and Uygun, N. 2005. The aphidophagus coccinellid (Coleoptera: Coccinellidae) species in Kahramanmaraş, Turkey. Turkish Journal of Zoology: 29: 1-8
Atlihan R. and Chi, H. 2008. Temperature-dependent development and demography of Scymnus subvillosus (Goeze) (Coleoptera: Coccinellidae) reared on Hyalopterus pruni (Geoffroy) (Homoptera: Aphididae). Journal of Economic Entomology 101: 325-333.
Attia, A.R. 2006. Biological control of the striped mealybug, Ferrisia virgata (Ckll.) (Homoptera: Pseudococcidae) on the mulberry tree, Morus alba using the coccinellid predator, Scymnus syriacus Mars. Egyptian Journal of Biological Pest Control 16: 45-50.
Fürsch, H. 1967. Scymnus (Sidis) hiekei Fürsch, als Feind von Pseudococcus citri Risso. Entomophaga 12: 309–310.
Kehat, M. and Greenberg, s. 1970. Survey and distribution of lady beetles [Coccinellidae] in citrus groves in Israel. Entomophaga 15: 275-280.
Iablokoff-Khnzorian, S. M. 1976. Die paläarktischen Genera der Marienkäfer - Tribus Scymnini nebst Bemerkungen über Scymnus fuscatus (Coleoptera, Coccinellidae). Entomologia Germanica 2: 374-80.
La Forgia, D. 2012. Morphological and biological observations on Scymnus apetzi Mulsant (Coleoptera: Coccinellidae). Thesis, University of Liège.
Plaut, N. 1965. On the phenology and control value of Stethorus punctillum Weise as a predator of Tetranychus cinnabarinus Boise. in Israel. Entomophaga 10: 133–137.
Rott, A.C. and Ponsonby, A.S. 2000. The effects of temperature, relative humidity and hostplant on the behaviour of Stethorus punctillum as a predator of the two-spotted spider mite, Tetranychus urticae. BioControl 45: 155-164.
Sabaghi, R., Sahragard, A. and Hosseini, R. 2011. Functional and numerical responses of Scymnus syriacus Marseul (Coleoptera: Coccinellidae) to the black bean aphid, Aphis fabae Scopoli (Hemiptera: Aphididae) under laboratory conditions. Journal of Plant protection Research 51: 423-428.
Uygun N., Atlihan R. 2000. The effect of temperature on develop¬ment and fecundity of Scymnus levaillanti. Biocontrol 45: 453–462.
Website http://www.pbase.com/tmurray74/lady_beetles_genus_scymnus https://www.google.co.il/search?q=Scymnus+syriacus&biw=1280&bih=687&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwjZqdOr24LSAhUFthoKHZL9AQMQsAQIFw&dpr=1.5