|Mccutcheon, G. - CLEMSON UNIVERISTY|
Submitted to: Journal of Agricultural and Urban Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 31, 2001
Publication Date: October 11, 2001
Citation: MCCUTCHEON, G.S., SIMMONS, A.M. RELATIONSHIP BETWEEN TEMPERATURE AND RATE OF PARASITISM BY AN ERETMOCERUS SP. (HYMENOPTERA: APHELINIDAE), A PARASITOID OF BEMISIA TABACI (HOMOPTERA: ALEYRODIDAE). JOURNAL OF AGRICULTURAL AND URBAN ENTOMOLOGY. 2001. v.18(2) p.97-104. Interpretive Summary: The B-strain sweetpotato whitefly (also called silverleaf whitefly) is an economically important pest of many field and greenhouse crops. Biological control can be a powerful tool in helping to regulate this whitefly. One of the most abundant native parasitoids of whiteflies on vegetables in South Carolina is a tiny parasitic wasp of the genus Eretmocerus. The wasp attacks and kills the nymphal stage of the whitefly. The effect of temperature on the rate of parasitism by the parasitic wasp was determined in the laboratory. The temperature range for optimum parasitism was about 80 to 95 degrees F. No parasitism was observed at either 59 or 113 degrees F. Adult wasps held at the highest temperature did not survive during 12 hours. These results will help in understanding environmental conditions under which whitefly parasites are most and least effective.
Technical Abstract: Knowledge of the ecology of beneficial organisms can help in determining their role in managing insect pests. The effect of temperature on rate of parasitism by Eretmocerus sp., an indigenous nymphal parasitoid of B- biotype sweetpotato whitefly, Bemisia tabaci (Gennadius) (=B. argentifolii Bellows & Perring), was examined on collard placed in plastic Petri dish cages in the laboratory over a range of constant temperatures (15 - 45 C). Host density was 30 to 40 whitefly nymphs per test arena. There was an increased rate of parasitism by Eretmocerus sp. as temperature was increased from 15 to 35, and parasitism declined at 40 C. There was a linear relationship between temperature and percentage parasitism when the 40 C treatment was not included in the data analysis. At 45 C, the adult parasitoid did not survive during the 12 h oviposition exposure period, and no parasitism was observed at this temperature. Among all temperatures, the erate of parasitism ranged from 0 to 30% of the whitefly nymphs. These results define the temperature range which is optimum (25 to 35 C) for parasitism by this species of Eretmocerus.