Potato Sprout Growth Suppression by Menthone and Neomenthol, Volatile Oil Components ofMinthostachys, Satureja, Bystropogon, andMentha Species

Abstract

The replacement of synthetic pesticides such as chlorpropham (CIPC) with effective potato sprout suppressants that have negligible environmental impact is needed due to increased concern for consumer health and safety. To date, however, only S-(+)-carvone, a monoterpene produced from caraway seeds, has been developed commercially as a competitive product to CIPC. Consequently, the effects of menthone and neomenthol vapor were compared to S-(+)-carvone for sprout suppressant efficacy as well as for effects on soluble sugar levels, respiration, and processing quality during high and low temperature storage. In the majority of treatments, tubers were enclosed in 3.8 1 glass jars at 25 C. Liquid test compounds were applied to a 10-cm-long x 2-cm-wide filter paper strip (Whatman No. 1) enclosed in each jar. Treatment with either menthone or S-(+)-carvone at 5 ul liquid/1 of treatment volume gave complete sprout suppression in non-dormant Russet Burbank tubers. An examination of changes in CO2 output, glucose, or sucrose levels over 4 wk at 10 C indicated that the effects of menthone and S-(+)-carvone were similar. In addition, menthone significantly inhibited sprouting without adversely affecting the percentage glucose content or sucrose content when this compound was applied at 4 ul/l to five-month-old, non-dormant tubers of AC Novachip, Russet Burbank, Shepody, and Snowden for two months at 10 C. Menthone and neomenthol were five to ten times more effective in sup pressing tuber sprouting than S-(+)-carvone when applied together at 0.5 ul/l each.