Rice Hispa Beetle (Trichispa Sericea), research in Pemba in 1993

agriculteur agricultores chemicals control cultural cultivation cultivo cultural control cultural methods experimentation exploitation agricole explotaciones agrarias farmers farms insecte nuisible lutte culturale mode de culture oryza pest control methods pest insects pesticide pesticides plaguicidas pratique culturale produit chimique recherche rendement rendimiento research tanzania tanzanie yields