PROC. ENTOMOL. SOC. WASH. 90(1), 1988. pp. 47-51 OCCURRENCE OF SELECTED FLOWER HEAD INSECTS OF CENTAUREA SOLSTITIALIS IN ITALY AND GREECE Stephen L. Clement .and Tizian.a Mimmocchi USDA. ARS. Biological Control of Weeds Laboratory— Europe. % American Embassy. Rome. Italy. APO New York 09794-0007: (SLC) USD.A. ARS Plant Introduction Station. 59 Johnson Hall, Washington State University. Pullman. Washington 99164-6402; (TM) Via Baldo degli Ubaldi 59. 00167 Rome. Italy, Abstract.— ^. 1984 survey was conducted in the south-Italian mainland and central Greece to locate sites where biocontrol specialists could collect insects of 6 promising biocontrol agents of yellow starthistle (YST), Centaurea solstitialis L.. for use in host specificity tests. Four of these flower head insects were found: Vwphora quadrifasciata and Terellia sp. (Diptera: Tephritidae) in Italy, and Eustenopiis hirtiis and Lariniis ciirtus (Coleoptera: Curculionidae) m Greece. I'rophora jaculata was the most abundant and ubiquitous species, but it is not a potential biocontrol agent because larvae will not develop m the heads of LI.S, forms of YST. New and supplementary information on the distribution of several YST flower head insects and the extent to which they attack heads in Italy and Greece are also presented and discussed in relation to published information. Centaurea solstitialis L. (yellow starthis-tle [YST]) is a Eurasian winter annual or biennial plant that has spread to the United States where it is a weed on over 3 million hectares in some western states (Maddo,\ et al. 1985. Maddox and Mayfield 1985). At-tempts to control YST biologically in the U.S. began in the 1 960's when a flower head gall fly. I'rophora jaculata Rondani {Dip-tera: Tephritidae). erroneously called U. si-runaseva (Hering) in some earlier refer-ences, was introduced from Italy (White and Clement 1987). Repeated efforts to estab-lish this fly on U.S. forms of YST were un-successful. However, weed biocontrol workers discovered that a flower head wee-vil from Greece (Bangasternus orientalis (Cap.): Coleoptera: Curculionidae) will at-tack and complete its development on U.S. plants (Maddox and Sobhian 1987). This weevil, first released in western U.S. in 1985. is now established in California (Maddox et al. 1986). We assumed that additional biological control agents would be needed to supple-ment the action of 5. orientalis so in 1984 we surveyed YST in Italy and Greece to locate populations of promising agents, namely the tephritid flies Chactorellia lie.xa-cliaeta (Loew). C sirunaseva. U. quadrifas-ciata (Meigen), and an undescribed Terellia species (= T. cf xirens (Loew) in Sobhian and Zwolfer [1985]). and the curculionid beetles Eustenopus hirtus (Waltl) (= E. cf ahbreviatus Faust in Sobhian and Zwolfer [1985]) and Larinus curtus Hochhut. We targeted these six flower head species for study because our preliminary work and un-published reports at the USDA. ARS Bio-logical Control of Weeds Laboratory— Eu-rope (BCWLE). Rome. Italy, indicated they had restricted host ranges in southern Eu-rope. More than one species may be con-fused under the name quadrifasciata (I. M. White, pers. comm.) and some populations of C hexachaeta may be separate species
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