A field study was conducted during 1991 to evaluate the effectiveness of Physalis tabaci (Gennadius) when grown with the commercial crop Gossypium barbedense L. Aldicarb at two rates was used in P. wrightii for control of B. tabaci. Three sampling methods: pan counts, leaf turns, and leaf counts measured B. tabaci numbers in both crops. Aldicarb treatment in the trap crop did significantly P. wrightii (P=0.000, df=2,240). Differences in numbers of adults observed on the two hosts were not significant. Analysis of aldicarb metabolite residues by high pressure liquid chromatography exhibited a pronounced dose effect (P=0.001, df=2, 22). The chemically treated trap crop did significantly protect the cotton crop from larger and more rapidly developing sweetpotato whitefly populations when compared to the untreated check.