The potential of natural naphthoquinones as the basis for a new class of pest control agents - an overview of research at IACR-Rothamsted

Two pesticidal naphthoquinones from Calceolaria andina (Scrophulariaceae) b oth contain a key structural feature not previously investigated in this gr oup of compounds. Structure-activity studies have led to the identification of analogues with commercial levels of activity. The primary mode of actio n in insects is by inhibition of complex III of the mitochondrial respirato ry chain. Species specificity has been attributed to differences in the sen sitivities of the target sites and whether the hydroxy group at position 2 is acylated. However, in comparative assays with some commercial insecticid es, these compounds exhibited unexpectedly poor dose-transfer to insects fr om leaf surfaces when formulated as emulsifiable concentrates. Volatilisati on and degradation were identified as key factors and performance improved with well-chosen formulations. (C) 2000 Elsevier Science Ltd. All rights re served.