Abstract
The fungal pathogen Rhynchosporium alismatis is being developed for biological control of starfruit (Damasonium minus), an important aquatic weed in Australian rice fields. The development of R. alismatis in starfruit differs between juvenile and adult plants. Juvenile starfruit plants are stunted as a result of fungal infection, while in adult plants, the main effect is necrosis and chlorosis of floating leaves. A conidial concentration of 1×104 conidia mL−1 was adequate to cause disease symptoms on floating leaves, but the stunting effect on juveniles was caused by concentrations of at least 1×105 conidia mL−1. To successfully inoculate juvenile plants, the water must be drained before inoculation to expose plants to the inoculum. The artificial addition of dew periods did not enhance disease development in plants. The stunting of juvenile starfruit plants caused by the infection of R. alismatis may give rice plants a competitive advantage over the weed at the seedling stage
Acknowledgments
This project was funded by the Rural Industries Research and Development Corporation. Mr Remy van der Ven (NSW Agriculture) helped with the design of the experiments and statistical analysis of the data.