FI-1045:: A profile of a commercially useful isolate of Metarhizium anisopliae var. anisopliae

The isolate FI-1045 is the basis of a mycoinsecticide, BioCane(TM) granules recently registered for the control of greyback canegrub, Dermolepida albohirtum (Coleoptera: Scarabaeidae: Melolonthinae) in Australian sugarcane Welds. The isolate was obtained from a naturally infected larva of D. albohirtum collected from Tully in north Queensland. The isolate can be distinguished from others infecting the same insect and also other species of canegrub by means of RAPD patterns and sequence data from the ITS region. A comparison of a stored FI-1045 isolate with three derived isolates which had different histories of host-passage, showed no variation in RAPD pattern. All isolates grew well at temperatures between 20 and 30degreesC but did not grow at 35degreesC and grew slowly at 15degreesC. However, on potato dextrose agar, the original FI-1045 grew more rapidly and did not produce as much pigment as the derived isolates. It is speculated that this difference was due to the storage method used with the original FI-1045 being stored at -70degreesC and the other isolates being freeze-dried. Bioassays against third instar greyback canegrubs gave a mean LC50 of 8.7 x 10(4) conidia g(-1) peat substrate after 10 weeks. Using Tenebrio molitor as a host, it was found that conidia taken directly from the infected insect were similar in virulence to the cultured FI-1045. Using injection of culture filtrate as the assay method, it was found that FI-1045 produced destruxins. In laboratory host range tests, a dose of 10(6) conidia g(-1) peat killed 96% of southern oneyear canegrubs, Antitrogus consanguineius, 85% of Lepidiota picticollis and less than 30% of the other five species of canegrub tested.