A total of 179 nonhalogenated compounds were evaluated as fumigants against larvae of Anastrepha suspensa (Loew). Larvae were exposed for 3 or 24 h to dosages ranging from 2.2 to 10.7 mg/liter. Results were compared with an ethylene dibromide standard. For 19 of the compounds, mortality of the larvae was greater than 50per thousand for 24-h exposures to 10.7 mg/liter of each compound. Of these 19 compounds, 3-buten-2-one, 2-propenyl, 1-isothisocyanato-2-propene, and 3-isothiocyanato-1-propyne killed all of the larvae exposed for 24 h to 2.2 mg/liter and greater than 93/500 of the larvae exposed for 3 h to 2.2 mg/liter. Five of six unsaturated aldehydes showed fumigant activity, as did all four isothiocyanates.