Diglyphus isaea Walker
(Recent data suggest that the entity known as Diglyphus isaea may actually be a complex of several sibling species).
Taxonomic placing: Insecta, Holometabola, Hymenoptera, Apocryta, Chalcidoidea, Eulophidae.
Geographic distribution: Europe, Asia, North Africa, and North America.
Morphology: These insects are shiny black, about 1.5-3 mm long, with short antennae and a yellow stripe on the hind legs. The larvae are whitish, about 3 mm in length, apodous.
Life history: Diglyphus isaea is an ectoparasitoid of larvae of Liriomyza spp. It locates these larvae through volatiles released by the damaged host plants, killing the larvae by stinging, feeding on the exuding body fluids and by parasitization. It requires about 160 day degrees to complete a generation and the threshold of development is around 9.0°C.
Economic importance: A prominent parasitoid of Liriomyza huidobrensis, Liriomyza trifolii and Phytomyza horticola in the Middle East. Mixtures of leguminous hosts (of Liriomyza) in the field lead to higher (about 70%) rates of D. isaea females.
Diglyphus isaea is currently on sale by several producers of beneficial organisms.
Monitoring: Yellow and blue sticky traps can be used to monitor the numbers of D. isaea in a greenhouse.
Effect of pesticides The translaminar Abamectin killed adult and larval D. isaea when applied directly. However, the pesticide had no similar effect when applied to host plants containing parasitoid larvae, nor was the longevity or percentage of the emerged adults affected. When applied in the field, abamectin and the insect growth regulatorcyromazine significantly reduced the numbers of D. isaea.
References
Abd-Rabou, S. 2006. Biological control of the leafminer Liriomyza trifolii by introduction, releasing and evaluation of the parasitoids Diglyphus isaea and Dacnusa sibirica on vegetable crops in greenhouses in Egypt. Archives of Phytopathology and Plant Protection 39: 439-443.
Cıvelek, H.S., Yoldas¸ Z. and Weintraub, P. 2002. The parasitoid complex of Liriomyza huidobrensis in cucumber greenhouses in Izmir Province, Western Turkey. Phytoparasitica 30: 285-287.
Finidori-Logli, V., Bagnéres, A.-G. and Clément, J.L. 1996. Role of plant volatiles in the search for a host by parasitoid Diglyphus isaea (Hymenoptera: Eulophidae). Journal of Chemical Ecology 22: 541–558.
Haghani, M., Fathipour, Y., Talebi, A.A. and Baniameri, V. 2007. Temperature-dependent development of Diglyphus isaea (Hymenoptera: Eulophidae) on Liriomyza sativae (Diptera: Agromyzidae) on cucumber. Journal of Pest Science 80: 71–77.
Kaspi, R. and Parrella, M.P. 2005. Abamectin compatibility with the leafminer parasitoid Diglyphus isaea. Biological Control 35: 172-179.
Musundire, R., Chabi-Olaye, A., Salifu, D. and Krüger, K. 2012. Host plant-related parasitism and host feeding activities of Diglyphus isaea (Hymenoptera: Eulophidae) on Liriomyza huidobrensis, Liriomyza sativae, and Liriomyza trifolii (Diptera: Agromyzidae), Journal of Economic Entomology 105: 161- 168.
Perdikis, C.Ch., Arvaniti, K.A. and Papadimitriou, D.M. 2016 Effects of sticky traps on Dacnusa sibirica, Diglyphus isaea and Nesidiocoris tenuis. Entomologia Hellenica 25: 1-11.
Sha, Z.-L., Zhu, C.-D., Murphy, R.W. and Huang, D.-W. 2007. Diglyphus isaea (Hymenoptera: Eulophidae): a probable complex of cryptic species that forms an important biological control agent of agromyzid leaf miners. Journal of Zoological Systematics and Evolutionary Research 45: 128-135.
Weintraub, P.G. 2001. Effects of cyromazine and abamectin on the pea leafminer Liriomyza huidobrensis (Diptera: Agromyzidae) and its parasitoid Diglyphus isaea (Hymenoptera: Eulophidae) in potatoes. Crop Protection 20: 207-213.
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