Timing and release rates for control of Bemisia tabaci (Homoptera: Aleyrodidae) by Nephaspis oculatus (Coleoptera: Coccinellidae) under confined conditions.

摘要

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 (60x60x60 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.