Promotion of nucleopolyhedrovirus infection in larvae of the silkworm, Bombyx mori (Lepidoptera: Bombycidae) by flufenoxuron

Flufenoxuron, an insect growth regulator (IGR), promoted infection of Bombyx mori nucleopolyhedrovirus (BmNPV) in 5th-instar B. mori larvae, when the chemical was dissolved in acetone and incorporated into the larval diet. The median lethal dose (LD50) or BmNPV was decreased as the concentration of flufenoxuron was increased. Undissolved flufenoxuron did not exert such an effect when it was incorporated into the diet as a powder form. Four other IGRs tested, chlorfluazuron, diflubenzuron, lufenuron and teflubenzuron, had no effect on BmNPV infection.