The interaction between Plectosporium alismatis and sublethal doses of bensulfuron-methyl reduces the growth of starfruit (Damasonium minus) in rice

Abstract

Plectosporium alismatis is a fungal pathogen that is being investigated as a biocontrol agent for suppressing starfruit (Damasonium minus), a significant weed of Australian rice fields. The aim of this research was to study the effect of the fungus on weed competition and its interactions with chemical herbicides. Conidial germination was significantly reduced by Londax® (bensulfuron-methyl), while MCPA had no effects. Glasshouse trials showed evidence of synergism between the fungus and 1.56% of the recommended dose of Londax®, in reducing the weed growth. The application of inoculum (conidia suspended in water) in the glasshouse eliminated weed competition with rice. In the field, the reduction in weed growth caused by the fungus did not significantly eliminate starfruit competition with rice. This is thought to be due to the presence of other weeds.

Keywords:

• Biological control
• bioherbicide
• rice
• disease
• Rhynchosporium
• Alismataceae
• synergy
• weed competition

Acknowledgments

This research was made possible thanks to the funding of the Rural Industries Research and Development Corporation, and in kind support of Cooperative Research Centre for Sustainable Rice Production. We would like to thank Ms Rhonda Smith for her technical support during this research.