Demographic studies of Oomyzus incertus (Hymenoptera: Eulophidae), a larval parasitoid of Hypera postica (Coleoptera: Curculionidae), treated with four organophosphorous insecticides

• Published in: Canadian entomologist 2005-08, Vol.137 (4), p.488-491
• Main Authors: Sabahi, Qodrat, Talebi, Khalil
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; chlorpyrifos; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on protozoa and invertebrates; etrimfos; Eulophidae; Fundamental and applied biological sciences. Psychology; Hypera postica; insect fertility; insect reproduction; Insecticides; life tables; malathion; nontarget organisms; parasitoids; phosalone; population growth; sublethal effects
• ISSN: 0008-347X; 1918-3240
• DOI: 10.4039/n04-067

The alfalfa weevil, Hypera postica (Gyllenhal) (Coleoptera: Curculionidae), can severely damage the first cutting of alfalfa, Medicago sativa L. (Fabaceae), in much of Iran. The pest has been parasitized by several parasitoids including Oomyzus incertus (Ratzeburg) (Hymenoptera: Eulophidae), a gregarious larval endoparasitoid. This wasp can parasitize up to 30% of weevil larvae in alfalfa fields in northern Iran. It produces three to four generations per year, and the female prefers the fourth instar of the host for oviposition. Each female lays 2 to 22 eggs per host, which hatch within 47–60 h. The life cycle is completed in about 2 weeks, upon pupation inside the host. This species is predominantly present during the summer months in alfalfa fields (Streams and Fuester 1967).