Biological control of the invasive alien weed Solidago canadensis: combining an indigenous fungal isolate of Sclerotium rolfsii SC64 with mechanical control

Abstract

Solidago canadensis L. is a major invasive weed that is highly tolerant to disturbances and difficult to control in China. In order to develop a rapid non-chemical control strategy for this weed in heterogeneous environments, we investigated different treatments including mechanical control (cutting and hoeing) and inoculation with an indigenous pathogen, Sclerotium rolfsii SC64, which was isolated from S. canadensis and applied by means of a solid formulation. Greenhouse and field trials were conducted to test how the control regimes (i.e. individual treatment methods, combination of these methods and different treatment timing) influence control efficiency. The fungal isolate S. rolfsii SC64 caused 70% plant mortality and fresh weight reduction of S. canadensis under 150 cm growth stage, and efficacy increased to 80% when the above-ground material was removed. However, the use of cutting, hoeing or treating with S. rolfsii SC64, on its own, did not provide sufficient control of S. canadensis. Cutting treatments performed in July and September only eliminated sexual reproduction of S. canadensis. Combination of cutting, hoeing and treating with isolate SC64 during the growing season in May, July and September was able to kill more than 90% of the ramets. This combination of methods not only eliminated sexual reproduction of S. canadensis, but also destroyed its underground stems and prevented its regrowth. Therefore, this integrated approach may provide an optima control strategy for S. canadensis.

Keywords:

• Canadian goldenrod
• mycoherbicides
• integrated weed management
• Sclerotium rolfsii
• Solidago canadensis

Acknowledgements

The authors thank Miss Min Zhang and Hui-zhi Lin for their technical assistance for part of this work, Miss Yu-fang Chen for her assistance with the graphics and revision for this manuscript. Financial support was provided by the 863 Hi-tech Research Project (2011AA10A206), Science & Technology Pillar Program of Jiangsu Province (BE2008313), Ph.D. Programs Foundation of Ministry of Education of China (20090097110018) and the 111 project.