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

Abstract

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 × 1012 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. Copyright © 1994, Wiley Blackwell. All rights reserved