Michaud: Impacts of Acaricides on Ladybeetles

Two ladybeetles, Cycloneda sanguinea (L) and Harmonia axyridis Pallas, were exposed to leaf residues and topical applications of five acaricide formulations commonly used in citrus production in Florida. Dicofol was the only compound demonstrating no toxicity to larvae of either species, even at twice the recommended rate. Abamectin + petrolium oil was the most toxic material; leaf residues applied at the recommended rate caused 100% mortality of both species. Diflubenzuron was toxic to larvae of both species as a leaf residue applied at twice the recommended rate, and to larvae of C . sanguinea when topically applied at the recommended rate. Fenbutatin oxide was toxic to larvae of C. sanguinea when topically applied at the recommended rate, and as a leaf residue applied at twice the recommended rate, but not to larvae of H. axyridis . Pyridaben was toxic to larvae of both species as a leaf residue applied at twice the recommended rate, and in topical application at the recommended rate. Adult beetles of both species survived topical applications of all materials without sustaining significant mortality over a 48-h period. Larvae of C. sanguinea surviving exposure to fenbutatin-oxide and diflubenzuron exhibited slower development than control larvae. Larvae of H. axyridis surviving exposure to abamectin + oil at 1/10 the recommended rate developed significantly faster than their control counterparts.