Do I need a dry-leaf for application of Kerb Flo 500 or ASTROKerb?

The propyzamide active in Kerb Flo 500 is soil acting so spraying wet weeds at run-off or light rainfall after application is not an issue.  Ideally, the rainfastness of ASTROKerb is 1 hour for the aminopyralid element.  Spraying on a drying leaf is OK but if rainfall falls within 1 hour and causes run-off efficacy may be reduced.  All applications should be made with due regard to water stewardship, i.e. do not spray where there is a risk of run-off to adjacent watercourses.