During the first phase of LUBILOSA, the technical feasibility of using such oil formulations against locusts was demonstrated in the laboratory, then field cage and arena trials. An extensive survey was launched in West Africa and the Arabian Peninsula to look for isolates virulent to locusts and grasshoppers, because few such isolates were available in public collections. The survey made use of a network of collaborators and came up with some 180 isolates, many of which belonged to Metarhizium acridum, some to other Metarhizium species and to Beauveria bassiana with a few records of Syngliocladium acridiorum (syn. Sorosporella). Laboratory screening of these isolates showed that M. acridum was easily the most virulent species under warm conditions (30 °C), and confirmed the selection of isolate IMI 330189 for further development. Subsequent trials in cages and arenas confirmed that oil formulations were infective even under very dry conditions. IMI 330189 and similar isolates were assigned to Metarhizium flavoviride in early papers, then Metarhizium anisopliae var. acridum, but are now described as Metarhizium acridum (Driver & Milner) J.F. Bisch., Rehner & Humber.