In a trial in Australia, 13 kg KNO3 per ha per spray was applied four times in a cotton crop and compared with the control. The first application was 7 days before flowering and the three applications after flowering were carried out at two-weekly intervals. The sprays significantly (P<0,05) reduced the mean disease incidence, disease severity and leaf shedding assessed (Table 1). Foliar application of KNO3 may be effective in reducing the effect of Alternaria leaf blight of cotton (Gossypium hirsutum) in north Australia.
Table 1. Mean incidence, severity and number of leaves shed due to Alternaria leaf blight of cotton at Katharine Res. Station 2004.
Bhuiyan, S.A., M. C. Boyd, A. J. Dougall, C. Martin and M. Hearnden. 2007. Effects of foliar application of potassium nitrate on suppression of Alternaria leaf blight of cotton (Gossypium hirsutum) in northern Australia. Australasian Plant Pathology 36: 462–465.