EVALUATION OF SERANGIUM-PARCESETOSUM (COLEOPTERA, COCCINELLIDAE) AS ABIOLOGICAL-CONTROL AGENT OF THE SILVERLEAF WHITEFLY (HOMOPTERA, ALEYRODIDAE)

The coccinellid predator from India, Serangium parcesetosum Sicard, wa s studied as a potential biological control agent of the silverleaf wh itefly, Bemisia argentifolii Bellows & Perring [also known as the swee tpotato whitefly, B, tabaci (Gennadius) Biotype B]. Studies were perfo rmed on prey preference, and effects of host plant on predation, and. temperature on life-history and predation rates. In one test, the pred ator was offered simultaneously 5 prey choices: con; earworm, Helicove rpa zea (Boddie) eggs; tobacco hornworm, Manduca sexta (L.) eggs; and approximate to 200 eggs and early instars of B. argentifolii reared on poinsettias, cantaloupes, or cucumbers. S. parcesetosum did not consu me any lepidopteran eggs: however, they devoured nearly all whitefly p rey offered averaging approximate to 600 prey per 24-h feeding period. Mean adult longevities were 27.6 d on cantaloupe, 24.5 d on cucumber, 44.7 d on hibiscus, and 27.8 d on tomato. Each S. parcesetosum adult consumed approximate to 170-200 whitefly eggs and immatures per 12-h f eeding period. The predation rate was highest on cucumbers, followed b y tomato and cantaloupe, and lowest on hibiscus. Under constant temper ature conditions of 20, 30, and 40 degrees C, adults survived best at 20 degrees C with a mean longevity of approximate to 75 d. Adults live d approximate to 25 d at 30 degrees C, whereas, 40 degrees C resulted in death within 3 d. Predation rate was found to increase with tempera ture. The mean number of total immature B. argentifolii consumed by S. parcesetosum adults was 138.9, 180.8, and 187.4 per 12-h feeding peri od at 20, 30, and 40 degrees C, respectively. The maximum cumulative l ifetime predation was measured at >10,000 whiteflies consumed in the m ost long-lived individuals, despite feeding only 12 h/d at 1- to 3-d i ntervals. Mean cumulative lifetime predation was measured at 4,909.5, 2,586.1, and 224.9 whiteflies at 20, 30, and 40 degrees C, respectivel y. Because of its voracity in both immature and adult stages, and its apparent preference for whiteflies, including B. argentifolii (compare d with lepidopteran eggs), S. parcesetosum is a promising biological c ontrol agent against the silverleaf whitefly.