Preliminary field tests on the use ofMetarhizium anisopliaefor the control ofNasutitermes exitiosus(Hill) (Isoptera: Termitidae)

The insect-pathogenic fungusMetarhizium anisopliaecaused heavy mortality in laboratory groups of the Australian termiteNasutitermes exitiosus(Hill) to which infected workers had been added. Conidia ofM. anisopliaestarted an epizootic when introduced into field colonies ofN. exitiosusnear Canberra, irrespective of whether the termites were treated by dusting or spraying in the mound itself, or dusting in nearby feeding sites. In some cases, the disease persisted for at least 15 weeks, and by this time few healthy termites could be found in almost half the treated colonies. Samples of workers taken from treated colonies showed high levels of contamination byMetarhizium, irrespective of the state of the colony, but the factors that inhibited the completion of fungal development in the nest are unknown.