CIPC vapour for efficient sprout control at low application levels

Isopropyl N-(3-chlorophenyl) carbamate (CIPC) is a growth inhibitor typically applied as a hot fog (spherical particles of about 5 μm diameter) on harvested potatoes to prevent sprouting during prolonged storage. Although particularly efficient in sprout control, deposition of solid CIPC particles on the potatoes increases the residue levels of the chemical on the tubers. The potential of CIPC to be used in the vapour phase for efficient sprout control at significantly lower application rates has been evaluated. First, CIPC vapour release rates from different hydrocolloid formulations were evaluated. From the investigated formulations (agar, gellan gum, κ-carrageenan, alginate), 1% gellan gum set with 0.002 M calcium ions appeared to result in the fastest vapour releasing formulation. At industrially relevant storage conditions (8 °C, 90% relative humidity) CIPC vapour release was significantly reduced. Vapour adsorption by tubers was then investigated and showed maximum of 2.5 mg kg−1 (mass of CIPC per mass of tubers) for washed, non-dormant tubers exposed to solid sources for 28 d. Efficient sprout control was indicated for tubers exposed to vapour sources and CIPC levels of 0.3 mg kg−1. Overall, the work indicates strong potential of CIPC vapour in efficiently preventing sprouting.