BIOLOGY OF PTEROLONCHE-INSPERSA (LEP, PTEROLONCHIDAE), A BIOLOGICAL-CONTROL AGENT FOR CENTAUREA-DIFFUSA AND CENTAUREA-MACULOSA IN THE UNITED-STATES

The moth, Pterolonche inspersa (Staudinger) (Lepidoptera: Pterolonchid ae): is widely distributed in southern Europe, north Africa, Turkey an d the former Soviet Union. It occurs in both thick and scattered stand s of knapweeds in disturbed sites, usually on sandy and/or stony soil. Larvae bore in the roots of diffuse and spotted knapweeds (Centaurea diffusa De Lamarck and C. maculosa De Lamarck). There is one generatio n per year in northern Greece, and larvae feed in the roots for about 11 months during the growing season (August-September, to the followin g July-August). In the laboratory garden, emergence took place between the second half of July and the end of August, with peak emergence du ring mid August. In the field, adults were observed from early to late July. Female moths oviposited on rosettes during the first ten days o f July and continued through the end of July. Eggs were laid singly or in groups of five or six, firmly attached to the leaves of the host p lant. In the laboratory, females mated within 24 hours of emergence an d the preoviposition period lasted 2.6 +/- 0.8 days. The oviposition p eriod lasted 7.4 +/- 2.2 days and the average number of eggs per femal e was 142.2 +/- 59.2. The incubation period was 12 +/- 4.7 days; the p upal stage lasted 14.7 +/- 2.4 days; and females lived 15.8 +/- 2.4 da ys, while males lived 10.7 +/- 1.4 days. First instar larvae failed to survive on economically important Compositae in the genera Cynara L., Helianthus L., Zinnia L. and Calendula L. (Dunn et al., 1989).