Charcoal rot of bushkiller (Cayratia spp.) caused by Macrophomina phaseolina (Tassi) Goidánich

In sugarcane fields of Okinawa Prefecture, Japan, populations of the aggressive bushkiller (Cayratia spp.) weed have increased explosively. Serious efforts are underway to control the weed. Bushkiller plants with yellowing of aerial parts and rotting of roots were found in fallow fields in Okinawa Prefecture, Japan during 2009. Fungal strain CJ-2, isolated from the affected plants, was strongly pathogenic on C. tenuifolia, and the rhizomes and roots of inoculated plants decayed. Based on its morphological characteristics and thermophilic nature, the fungus was identified as the charcoal rot fungus Macrophomina phaseolina, a soilborne pathogen. This report is the first of charcoal rot on Cayratia spp. caused by M. phaseolina.