Field studies were conducted during a two-year period to investigate the effects of CEPA (2-chloroethylphosphonic acid) on flue-cured tobacco. A quick (3-4 days) yellowing response of physiologically responsive leaves (midway between maturity and ripeness) was noted. Initially unresponsive leaves were observed to yellow 10-14 days post-treatment only if the chemical had contacted the leaves directly. Low rates of CEPA stimulated starch accumulation in mature, green leaves; higher rates resulted in decreased starch concentration and some sugar accumulation. CEPA dosages above 60-90 mg/plant were not additionally beneficial with respect to whole-plant yellowing. Seasonal effects on the yellowing response were observed.

(Full article published with kind permission from "Tobacco International")