A first examination of the interaction between Alternaria alternantherae and Agasicles hygrophila on Alternanthera philoxeroides

Abstract

The use of an alligatorweed (Alternanthera philoxeroides) insect biological control agent, alligatorweed flea beetle (Agasicles hygrophila Selman and Vogt), and the leaf spot plant pathogen, alligatorweed leaf pathogen (Alternaria alternantherae Holcomb and Antonopoulis), may provide enhanced control of alligatorweed infestations if competitive interactions between agents are minimal and damage to host plants are synergistic. However, to assess suitability of co-use of these two agents, it is necessary to first identify whether introduction of one may impact performance of the other. This technical note details a first examination of competitive interactions between A. hygrophila and A. alternantherae under varied temperature and host nutritional conditions. Presented are the results of laboratory experimentation and recommendations for future research.