Release and Establishment of Zygogramma suturalis F (Coleoptera: Chrysomelidae) in Croatia for Control of Common Ragweed (Ambrosia artemisiifolia L.)

Common ragweed (Ambrosia artemisiifolia L.) is an important weed in some parts of Europe. After determining that native natural enemies in Croatia had little influence on controlling this weed, we introduced the beetle Zygogramma suturalis F. from the United States and obtained data on its biology and ecology. We released the beetle in the held at three sites near Bjelovar, Zagreb, and Zadar beginning in 1985. Establishment was confirmed at the Zagreb and Zadar sites from releases made in 1988, but field populations of the beetle remained low through the fall of 1991.