Effect of moulting inhibitors (buprofezin and diflubenzuron) on Acyrtosiphon pisum (Hom., Aphididae), Planococcus citri (Hom., Pseudococcidae) and Quadraspidotus perniciosus (Hom., Diaspididae).
In laboratory studies, neither buprofezin nor diflubenzuron showed activity against the different developmental instars of the aphid Acyrthosiphon pisum, while diflubenzuron was ineffective against the pseudococcid Planococcus citri and the diaspidid Quadraspidiotus perniciosus. Buprofezin at 0.05% a.i. effectively inhibited development of the 1st-instar nymph of P. citri, while concentrations lower than this resulted in a marked decrease in the egg production of surviving females. The relative insensitivity of immature stages of these species of Hemiptera indicates that during evolution their UDP-N-acetylglucosamine transport has became modified compared with other insect groups. This may be especially relevant for the Aphidoidea which are insensitive to both insect growth regulators. It is suggested that Applaud 25 WP and 50 WP, which contain buprofezin, may provide an alternative to Dimilin 25 WP, which contains diflubenzuron, in integrated control programmes.