Another promising class of fumigants is gaseous allyl isothiocyanates (AIT) that inhibit bacteria and postharvest fungal pathogens at concentrations ranging from 100 to 1000 μg AIT L-1 (Delaquis and Sholberg 1997). Mari et al. (2008) showed that 4-methylthiobutyl-ITC was the most effective isothiocyanate that was tested having the lowest ED95 of 0.10 mg
L-1 for Monilinia laxa conidia and 0.52 mg L-1 for mycelium. In reviewing non-conventional methods for control of postharvest pear diseases Mari et al. (2003) divide emerging technologies into the following three components; 1) application of natural antagonistic microorganisms, 2) application of natural antimicrobial substances such as the ITC compounds, and 3) application of sanitizing products. Sanitizing fumigants include products such as chlorine dioxide and ozone used in circulation water or as fumigants for use in storage rooms (Sholberg 2004; Linton et al. 2006). Although many of these products are promising and need further research this review will focus only on acetic acid (AA) including vinegar, and the plant volatiles, hexanal and 2-trans-hexenal used as fumigants for direct control of plant pathogens on produce and/or as sanitizers for the postharvest environment. Acetic acid vapor was previously reviewed by Sholberg et al. (1998) but plant volatile com- pounds do not appear to have been reviewed for control of postharvest decay. Since the first review on AA vapor many new research articles have been published on it and a better understanding of the conditions for its use have emerged