Occurrence and distribution of Ambrosia antemisiifolia and its two natural enemies in Guangdong Province.
The first Chinese record of the common ragweed, Ambrosia artemisiifolia L. was in 2002 in Guangdong Province and since then this invasive weed has spread quickly throughout the Province. In order to slow its spread, the occurrence and distribution of ragweed and its insect predators were surveyed. The results show that ragweed is mainly distributed in the Shaoguan and Qingyuan areas of northern Guangdong, Fengkai in western Guangdong and the Meizhou area of northeastern Guangdong. Two insect predators of ragweed were identified; Epiblema strenuana W. and Ophraella communa L. Although E. strenuana has a wider distribution, O. communa is more effective in controlling ragweed. The role of highways in assisting ragweed dispersion and the potential for insect predators to reduce its spread are discussed.