Abstract: The UK grain industry houses many tons of its produce in grain stores every year,however a complex of insect pests may infest these stores and many tons of pesticide are appliedto control the problem. Control of insect pests within the grain store environment is becomingmore important as EU legislation is restricting the number of chemical pesticides available foruse and alternative methods of control need to be sought. Entomopathogens provide an importantalternative for chemical control and Beauveria bassiana is a very promising candidate for furtherdevelopment. Different isolates of B. bassiana were isolated from insects found within grainstores and after investigation, two isolates were chosen for further study. These isolates werefurther researched so that they would have improved efficacy in grain store conditions.Laboratory investigations optimized the mass production technology used in order to produceconidia that are more tolerant and effective in drier environments. Formulations of both isolateswere investigated to ensure that the conidia remain viable and are suitable for a final product.Efficacy of the mass produced and formulated conidia was tested at both a lab and pilot scalelevel within a grain store environment. Results from the project have been very promising and anoverview of findings is reported here.