Leptomastix
Systematic position: Insecta, Holometabola, Hymenoptera, Apocrita, Chalcidoidea, Encyrtidae.
Geographical distribution: Cosmopolitan, wherever the mealybug hosts occur.
Morphology: About 2-3 mm in length, body yellow-red, the abdomen in some species darker. Legs and distal antennal segments dark.
Hosts: Various mealybugs.
Life cycle: Species of Leptomastix are solitary endoparasitoids of mealybugs. They insert a single egg into the host, develop therein in 3-4 weeks, the mealybug meanwhile becoming a brown mummy. Adults may live for several weeks, feeding on honeydew or nectar.
Economic importance: Several species are used in commerce to control pestiferous mealybugs. In the Middle East the main species include:
Leptomastix algirica Trjapitzin
A Mediterranean species that attacks several mealybugs, including Pseudococcus cryptus and Pseudococcus longispinus. Its eggs were encapsulated in the bodies of Planococcus citri and other species of Planococcus. In contrast to other species of Leptomastix, it has almost-black wings, which impart a dark aspect to its body.
Leptomastix dactylopii Howard
A widely distributed species that occurs in or was introduced into most regions, and attacks about 20 mealybug species. The females prefer third-instar nymphs and young adult females as hosts. The adults live 3-4 weeks and fecundity comes to 60-100 eggs/female, depending on available nutrients. It had been used in Turkey against P. citri since 1970, and has completely controlled this pest in Indian guava orchards as well as in Australian citrus groves. In Egypt, where it was reared from Maconellicoccus hirsutus and Planococcus ficus, parasitization rates were only up to 8%. In some mealybug hosts the parasitoid’s egg is encapsulated. When attacking P. citri, the color of the host plant (Coleus blumei Benth.) affected the size, fecundity and survival of L. dactylopii, being larger, higher and better on red cultivars than on green ones. The coccinellid predator Nephus kreissli Fürsch and Uygun could not feed on mummified P. ficus in which L. dactylopii was developing. The systemic Flonicamid and an insect growth regulator had little effect on L. dactylopii.
Leptomastix flava Mercet
This species occurs in southern Europe and North Africa. In Egypt it attacked up 27% of Nipaecoccus viridis.
Leptomastix nigrocoxalis Compere
This species is widely distributed in Africa and Asia. In Egypt it attacks N. viridis (8.5-21% parasitism) and M. hirsutus (2.5-13% parasitism).
References
Anga, J.-M. and Noyes, J.S. 1999. A revision of the African and Malagasy species of the genus Leptomastix (Hymenoptera, Encyrtidae), parasitoids of mealybugs (Homoptera: Pseudococcidae). Bulletin of The Natural History Museum (Entomology Series) 68: 93-128.
Attia, A.R. 2012. Hymenpterous parasitoids as bioagents for controlling maybugs (Hemiptera: Pseudococcidae) in Egypt. Egyptian Academy Journal of Biological Sciences 5: 183 -192.
Blumberg, D. and van Driesch, R.G. 2001. Encapsulation rates of three encyrtid parasitoids by three mealybug species (Homoptera: Pseudococcidae) found commonly as pests in commercial greenhouses. Biological Control 22: 191-199.
Cloyd, R.A. and Dickinson, A. 2006. Effect of insecticides on mealybug destroyer (Coleoptera: Coccinellidae) and parasitoid Leptomastix dactylopii (Hymenoptera: Encyrtidae), natural enemies of citrus mealybug (Homoptera: Pseudococcidae). Journal of Economic Entomology 95: 1596-1604.
David-Levanony, L. Blumberg, D., Gafny, R. and Mendel, Z. 2001. Biology and host range of Leptomastix algirica, an unfamiliar parasitoid of the cryptic mealybug, Pseudococcus cryptus. Phytoparasitica 29: 72.
Mani M, 1994. Effectiveness of the exotic encyrtid parasitoid, Leptomastix dactylopii How. in the control of mealybug, Planococcus citri (Risso) in guava orchards. Journal of Entomological Research 18: 351-355.
Muştu, M. and Kılınçer, N. 2014. Intraguild predation of Planococcus ficus parasitoids Anagyrus pseudococci and Leptomastix dactylopii by Nephus kreissli. Biocontrol Science and Technology 24: 257–269.
Smith, D., Papacek, D.F. and Murray, D.A.H. 1988. The use of Leptomastix dactylopii Howard (Hymenoptera: Encyrtidae) to control Planococcus citri (Risso) (Hemiptera: Pseudococcidae) in Queensland citrus orchards. Queensland Journal of Agricultural and Animal Sciences 45: 157-164.
Tingle, C.C.D. and M. J. W. Copland, M.J.W. 1989. Progeny production and adult longevity of the mealybug parasitoids Anagyrus pseudococci, Leptomastix dactylopii, and Leptomastidea abnormis (Hym.: Encyrtidae) in relation to temperature. Entomophaga 34: 111-120.
Yang, J. and Sadof, C.S. 1997. Variation in the life history of the citrus mealybug parasitoid Leptomastix dactylopii (Hymenoptera: Encyrtidae) on three varieties of Coleus blumei. Environmental Entomology 26: 978-982.
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