Complete Host Range Testing on Common Reed with Potential Biological Control Agents and Investigation into Biological Control for Flowering Rush
Centre for Agriculture and Bioscience International (CABI) Delemont Switzerland
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The noctuid moths, Archanara geminipuncta and A. neurica, were selected as the most promising candidates for biological control of common reed. Successful larval development was only found on Phragmites spp., but development was also possible on the native North American subspecies P. australis subsp. americanus. However, open-field oviposition tests showed a strong preference of females for both European and introduced P. australis. Because of the higher egg mortality on native reed, the authors expect any impact of A. neurica and A. geminipuncta on the native reed P. australis subsp. americanus to be negligible, should the noctuids be released in North America. A biological control project for flowering rush was started in spring 2013. According to the authors literature survey, the semi-aquatic weevil, Bagous nodulosus, is the most promising potential agent for biological control. During various field surveys in Northern Germany, the Czech and Slovak Republics, Hungary, Poland, and Serbia, the authors collected several hundred adults of B. nodulosus, established a rearing colony, and started with sequential no-choice oviposition tests. So far, no eggs were found on any of the 22 test plants offered. The authors also found the other five herbivore species recorded as monophagous on flowering rush and started work with a second weevil, B. validus.