Biological control of lippia (Phyla canescens): surveys for the plant and its natural enemies in Argentina

摘要

Lippia, Phyla canescens (Kunth) Greene (Verbenaceae) is a fast-growing, mat-forming plant native to South America. It is a weed in Australia, where it was introduced as an ornamental during the nineteenth century. The knowledge about the biology of lippia is currently limited to unconcluded taxonomical studies; there is scarce information about the ecology and natural enemies in the native range. Surveys for the plant and its natural enemies were initiated in Argentina in 2005 to determine its distribution and to search for possible biological control agents, both insects and phytopathogens. We have found Phyla sp. in 54 out of 102 sites sampled, mostly east of 66°W, circumscribing the weed to the Chaco Domain. In places where the plant was present, at least 20 arthropods and 16 fungi were found. Among insects, the most promising candidates are three flea beetles (Chrysomelidae): two species of Longitarsus and Kuschelina bergi Harold. Pathogens include the rust Puccinia cf. lantanae Farl., Cercospora cf. lippiae Ellis and Everh. and three Colletotrichum spp., associated with leaf spots and stem cankers. Additional information on their biology and host specificity is required to propose any of these as biological control candidates.