Systematic position: Insecta, Holometabola, Hymenoptera, Apocrita, Chalcidoidea, Scelionidae.

Morphology: Very small insects with a mostly black body and yellowish legs.

Geographic distribution: Cosmopolitan, consisting of about 170 named species.

Life history: Species of Trissolcus are egg parasitoids of various Heteroptera, including, in the Middle East, the pestiferous Sunn pest (Eurygaster integriceps) and Aelia rostrata. When these wheat-infesting hosts are unavailable, Trissolcus attacks eggs of various Pentatomidae and Scutelleridae. Trissolcus semistriatus Nees is strongly attracted to the odor of wheat, a host plant of these pests. Its fecundity came to about 110 eggs/female at 32°C, but only to ca 50 eggs/female at 17°C, and at 20°C it lived about 3 weeks. The calculated threshold of development of this species was 11.8°C, 116 day degrees are required to complete a generation, and it raises 8-9 annual generations in Turkey. The comparative values for T. rufiventris Mayr are 15.5°C, and 125 day degrees, and for T. simony May, 12.5°C, and 166 day degrees.

Economic importance: Several species of Trissolcus are major biological control agents of various pests, such as Nezara viridula in various regions. In the Middle East they are important enemies of E. integriceps and A. rostrata. Parasitism of E. integriceps by Trissolcus grandis Thomson ranged from 60 to 84% in Syria. Mass rearing, and low-temperature conserving methods for these species (e.g. T. semistriatus) have been developed, allowing their field release in very large (inundative) numbers.

Effect of pesticides: Trissolcus rufiventris is very susceptible to organophophates and pyrethroids.


Clark, A.R. 1990. The control of Nezara viridula with introduced egg parasitoids in Australia – a review of a landmark example of classical biological control. Australian Journal of Agricultural Research 41: 1127-1146.

Gözüaçık, C. and Yiğit, A. 2015. The alternative hosts of Trissolcus spp., egg parasitoids of Sunn pest and host-parasitoid interactions in southeastern Anatolia region, Turkey. In: 2nd Internatiuonal Symposium for Agriculture and Food. Ohrid, Republic of Macedonia.

İslamoğlu, M. 2011. Mass rearing and release of the egg parasitoid, Trissolcus semistriatus Nees. (Hymenoptera: Scelionidae), a biological control agent of the Sunn pest, Eurygaster integriceps Put. (Heteroptera: Scutelleridae) in Turkey. Egyptian Journal of Pest Control 21:131-136.

İslamoğlu, M., and Tarla, S. 2013. Some biological properties of Trissolcus semistriatus (Nees) (Hymenoptera: Scelionidae) adults stored at different temperatures. Bulgarian Journal of Agricultural Science 19: 1364-1371.

Kıvan, M. and Kılıç, N. 2004. Parasitism and development of Trissolcus simoni in eggs of different host species. Phytoparasitica 32: 57-60.

Kıvan, M. and Kılıç, N. 2006. Age‐specific fecundity and life table of Trissolcus semistriatus, an egg parasitoid of the sunn pest Eurygaster integriceps. Entomological Science 9: 39-46.

Kıvan, M. and Kılıç, N. 2006. A comparison of the development times of Trissolcus rufiventris (Mayr) and Trissolcus simony Mayr (Hym.: Scelionidae) at three constant temperatures. Turkish Journal of Agriculture and Forestry 30: 383-386.

Koçak, E. and Kilinçer, N. 2003. Taxonomic studies on Trissolcus sp. (Hymenoptera: Scelionidae), egg parasitoids of Sunn pest (Hemiptera: Scutelleridae: Eurygaster sp.), in Turkey. Turkish Journal of Zoology 27: 301–317.

Koçak, E., Kodan, M. and Babaroglu, N. 2008. Bazı insektisitlerin Kımıl (Aelia rostrate Boh., Het.: Pentatomidae) Yumurta Parazitoiti Trissolcus rufiventris Mayr (Hymenoptera: Scelionidae)’e Etkileri Üzerinde Arastırmalar. Süleyman Demirel Üniversitesi Ziraat Fakültesi Dergisi 3: 52-59 (in Turkish with an English abstract).

Orr, D.B. 1988. Scelionid wasps as biological control agents: a review. Florida Entomologist 71: 506–28.

Trissi A.N., El Bouhssini M., Ibrahem J., Abdulhai M., Parker B.L., Reid W. and El-Haramein F.J. 2006. Effect of egg parasitoid density on the population suppression of Sunn Pest, Eurygaster integriceps (Hemiptera: Scutelleridae), and its resulting impact on bread wheat grain quality. Journal of Pest Science 79: 83-87.