
%0 Journal Article
%A McKay, AG 
%A Floyd, RM 
%A Boyd, CJ 
%T Phosphonic acid controls downy mildew (<I>Peronospora parasitica</I>) in cauliflower curds
%J Australian Journal of Experimental Agriculture
%D 1992/01/01
%V 32
%N 1
%P 127-129
%K 
%R https://doi.org/10.1071/EA9920127
%U https://www.publish.csiro.au/paper/EA9920127 
%X Postharvest development of downy mildew (Peronospora parasitica) symptoms in export cauliflower curds has resulted in economic losses to growers in south-western Australia. Neutralised phosphonic acid sprays applied onto cauliflowers in the field within 3 weeks of harvest reduced this disease. Two applications of 2.4 kg a.i./ha, 21 and 7 days before harvest, reduced the incidence of curds affected by downy mildew from 92% in untreated plots to 8%. The maximum phosphonate residue in curds at harvest was 12 µg/g, while control curds contained no detectable phosphonate. No effects of phosphonic acid on crop appearance or maturity were observed, and while a small (8%) reduction in curd weight was significant (P = 0.039), there was no yield trend with increasing phosphonic acid rate. 
