Preliminary Field Trial on the Control of Phaulacridium vittatum (Sjöstetd) (Orthoptera: Acrididae) Populations with Metarhizium flavoviride Gams and Rozsypal (Deuteromycetina: Hyphomycetes)

Conidia of Metarhizium flavoviride isolate F1985 were applied to a field population of Phaulacridium vittatum near Dalgety, New South Wales as an oil‐based ULV spray and an oil/water emulsion high volume spray to 0.25 ha plots at a rate equivalent to 3.56 × 10 12 conidia/ha. As a comparison, one plot was treated with fenitrothion e.c. at 240 g.a.i./ha. the M. flavoviride high volume treatment reduced P. vittatum densities from 18–28 m −2 to < 8 m −2 within 10 d. the density was reduced by a similar extent by the insecticide treatment. the ULV treatment showed a delayed decline, occurring between day 10 and 17. the control plots also showed a decline at this time which was due to spray drift and dispersal. One month after treatment densities averaged 4.5m −2 in M. flavoviride treatments, 5.0 m −2 in the insecticide treatment and 8.5m −2 in control plots. P. vittatum field collected up to 32 d after treatment sporulated after death in the laboratory suggesting lateral transmission of the disease in the field. This is the first demonstration of carryover of M. flavoviride in the field.