Cj. Lomer et al., CONTROL OF GRASSHOPPERS, PARTICULARLY HIEROGLYPHUS-DAGANENSIS, IN NORTHERN BENIN USING METARHIZIUM-FLAVOVIRIDE, Memoirs of the Entomological Society of Canada, (171), 1997, pp. 301-311
Trials on the use of Metarhizium flavoviride Gams and Roszypal conidia
in oil-based formulation for the control of grasshoppers, particularl
y Hieroglyphus daganensis Krauss, in Malanville, north Benin, are desc
ribed. Preliminary work examined sprayer types, application rate, and
time of application. In a trial on 4-ha plots with three replicates, M
. flavoviride mycoinsecticide application to H. daganensis nymphs resu
lted in field population reductions of 70% after 14 days. In samples i
ncubated in cages, mortality was higher in the samples taken 3 or 7 da
ys after application than in the sample taken immediately after applic
ation, indicating the possibility of residual pick-up compared with di
rect spray impact in this environment. Significant mortality was still
bring observed in samples collected 37 days after application; to inv
estigate this further, a method for bioassaying the spore load in the
field was developed and used to monitor the spore load in the field. T
he possibility that the results indicate the occurrence of secondary i
nfections resulting from horizontal transmission of M. flavoviride is
discussed.