none. Sphecophaga vesparum; HYMENOPTERAN-HOSTS; Vespa orientalis; Nest parasitization observations, Israel Vespa orientalis; HYMENOPTERAN-PARASITES; Sphecophaga vesparum; Nest parasitization observations; ISRAEL-; South; Nest parasitization by Sphecophaga vesparum, observations Vespa orientalis F. (Hymenoptera: Vespidae), a major pest of apiculture, indirectly disrupts pollination of fruit ad vegetable crops, and constitutes a public health menace. Control methods are imperfect, labor-intensive, and entail the use of medically and environmentally dangerous chemicals. A parasitic wasp, Sphecophaga vesparum Curtis (Hymenoptera: Vespidae), has been found to attack a large proportion (up to 100%) of observed V. orientalis nests in southern Israel. Within these nets, 2.5-95.1% of host cells were parasitized by three to seven individuals. Heavily parasitized nests showed considerable reductions in the proportion of queen cells.