PRELIMINARY FIELD TRIAL ON THE CONTROL OF PHAULACRIDIUM-VITTATUM (SJOSTETD) (ORTHOPTERA, ACRIDIDAE) POPULATIONS WITH METARHIZIUM-FLAVOVIRIDE GAMS AND ROZSYPAL (DEUTEROMYCETINA, HYPHOMYCETES)

Conidia of Metarhizium flavoviride isolate F1985 were applied to a fie ld 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 x 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 dens ities 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 show ed a delayed decline, occurring between day 10 and 17. The control plo ts 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. flavo viride treatments, 5.0 m-2 in the insecticide treatment and 8.5m -2 in control plots. P. vittaium field collected up to 32 d after trea tment sporulated after death in the laboratory suggesting lateral tran smission of the disease in the field. This is the first demonstration of carryover of M. flavoviride in the field.