ABSTRACT
In three field experiments, the influence of daminozide as Alar® (Uniroyal Inc.) or Dazide® (Fine Agrochemicals Ltd.) on both winter- and spring-sown Vicia faba L. was assessed. Full-dose-rate response curves were constructed using up to 3.2 kg ha−1 of daminozide and comparing a range of adjuvants including alkyl phenol ethylene oxide condensate (Agral®, ICI); ethoxylated tallow amine (Hyspray®, Fine Agrochemicals Ltd); acidified soyal lecithin (LI700, Loveland Industries Inc.), and emulsified mineral oil (Actipron®, Bayer Co.).
Daminozide altered the partition of plant phytomass in favor of pods at the expense of the lower stem. Emaciation of this stem increased the propensity of the stand to brackling (lodging). The influence of daminozide on V. faba could thus be assessed by calculating the fraction of phytomass present as pods (ρf) and by measuring the degree of brackling (ℓ).
Relating both ρP and ℓ to the rate of daminozide applied suggested that the rate of response was strongly dependent on adjuvant chemistry. Efficiency of response was maximized by adding LI700 to the spray solution, followed by Actipron, Hyspray, and Agral. Increasing ρp promoted seed yield when ℓ was not increased over a threshold value.
