Showing papers in "Plant protection quarterly in 1996"

The contribution of biological control to the management of thistles.

Abstract: Summary CSIRO Division of Entomology has twomajor projects on the biological controlof carduine thistles, one against noddingthistle ( Carduus nutans ) and another forscotch and Illyrian thistles ( Onopordumacanthium and O. illyricum ). The strate-gies for biological control of these targetthistles are similar, although the agentsused are different. Since thistlepopulations depend solely on seedlingestablishment for recruitment, the prior-ity area in both projects is to limit seed-ing, with the ultimate aim to reduce thesoil seed banks found in Australia to themuch lower levels found in Europe. Bothprojects include insects that attack the ca-pitula and thus have a direct impact onseeding; both also have insects that attackvegetative parts of the plant and thus in-directly limit seed production. The roleof biological control in an overall man-agement strategy for these two groups ofthistles is briefly discussed. Introduction CSIRO Division of Entomology is cur-rently conducting two biological controlprojects on carduine thistles. The targetsare nodding thistle,