Timing and Release Rates for Control of Bemisia tabaci (Homoptera: Aleyrodidae) by Nephaspis oculatus (Coleoptera: Coccinellidae) under Confined Conditions

Abstract

The potential of a lady beetle, Nephaspis oculatus (Blatchley), to serve as a biological control agent of the sweetpotato whitefly, Bemisia tabaci (Gennadius) Biotype “B” (= B. argentifolii Bellows & Perring), was evaluated on hibiscus under confined conditions, in large cages (60 × 60 × 60 cm) and on sweetpotato leaves in small clear cup cages (0.9 L). Nephaspis oculatus suppressed B. tabaci populations and provided marketable hibiscus plants when released 1 d after whitefly introduction in large cages at ratios of 1:4 and 1:20 beetle:whitefly. When beetles were released 7 d after the whitefly infestation, significant pest reduction and marketable plants were obtained with the 1:4 beetle:whitefly ratio but not the 1:20 ratio. In clear cup cages on sweet potato leaves, significant suppression was obtained at beetle:whitefly ratios of 1:6.7, 1:10 and 1:20 when N. oculatus was released 1 d after the whitefly infestation. These results help define release parameters for successful use of N. oculatus as a biological control agent of whiteflies under confined conditions.