CONTROL OF GRASSHOPPERS, PARTICULARLY HIEROGLYPHUS DAGANENSIS, IN NORTHERN BENIN USING METARHIZIUM FLAVOVIRIDE

Abstract

Trials on the use of Metarhizium flavoviride Gams and Roszypal conidia in oil-based formulation for the control of grasshoppers, particularly Hieroglyphus daganensis Krauss, in Malanville, north Benin, are described. 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 resulted in field population reductions of 70% after 14 days. In samples incubated in cages, mortality was higher in the samples taken 3 or 7 days after application than in the sample taken immediately after application, indicating the possibility of residual pick-up compared with direct spray impact in this environment. Significant mortality was still being observed in samples collected 37 days after application; to investigate this further, a method for bioassaying the spore load in the field was developed and used to monitor the spore load in the field. The possibility that the results indicate the occurrence of secondary infections resulting from horizontal transmission of M. flavoviride is discussed.

Operational-scale application of entomopathogenic fungi for control of Sahelian grasshoppers

“…Cunningham 1992 ;Johnson et al 1992 ;Lobo-Lima et al 1992 ;Prior et al 1992 ;Baker et al 1994 ;Zimmermann et al 1994) and several studies have demonstrated significant population reductions of grasshoppers following microbial applications (e.g. Johnson & Goettel 1993 ;Baker et al 1994 ;DouroKpindou et al 1995 ;Thomas et al b, 1997Lomer et al 1997 ;Milner 1997). However, these have been at relatively small experimental scales (under 10 ha) against species or life stages of limited mobility.…”

“…Control plots received no spray treatments as previous studies have shown the blank oil formulation to have negligible effects on grasshopper populations in the field (e.g. Shah 1994 ;Lomer et al 1997). Furthermore, the trial was designed to test the efficacy of the biopesticide ' product ' which includes any impact of the formulating agents.…”

Coping with crowds: Density-dependent disease resistance in desert locusts

“…acridum (isolate IMI 330189) with a micro applicator. This method of application is noninvasive (the suspension is placed on the insect's cuticle beneath the dorsal pronotal shield), and studies have shown that the blank oil formulation has negligible effects on mortality and behavior in the laboratory or field (21)(22)(23)(24). Spore concentration in the suspension was adjusted to give 1 ϫ 10 4 spores per insect, and an equivalent number of solitaria and gregaria locusts were left untreated as controls.…”

Biorational insecticides in pest management

“…acridum) has been found effective against the brown locust Locustana pardalina in Africa, 66) Locusta migratoria in Madagascar, 67) and the Australian plague locust Chortoicetes terminifera and L. migratoria in Australia. 68) With variable success, M. flavoviride has also been tested against the tree locust Anacridium melanorhodon in Sudan, 69) the rice grasshopper Hieroglyphus daganensis in Benin, Mali and Senegal 70) and the desert locust Schistocerca gregaria in Mauritania. 71) In the case of this highly mobile insect, an estimated plot size larger than 1000 ha would be necessary and such trials are expected to take place within the FAO Emergency Prevention Program.…”