Evaluation of phosphonate fungicides for control of foliar and tuber late blight of potato

• Published in: Phytopathology Vol. 96; no. 6; pp. S186 - S187
• Main Authors: Mayton, H, Fry, W E
• Format: Journal Article
• Language: English
• Published: 01-06-2006
• Subjects: Phytophthora infestans; Solanum tuberosum
• ISSN: 0031-949X

Most commercially cultivated potato varieties are susceptible to late blight, caused by Phytophthora infestans, therefore, an intensive fungicide schedule is needed to minimize loss of production. One potential method to reduce applications of conventional fungicides is to incorporate biopesticides into the potato production system. Four phosphonate (dipotassium phosphonate/ dipotassium phosphate) biopesticides; Biophos, Fosphite, Prophyte, and Phostrol were evaluated in the field for efficacy against P. infestans. Phosphonates were assessed alone, in combination with, and in alternation with the conventional fungicide Bravo WS. Aliette (aluminum phosphonate) a conventional fungicide, was also evaluated. All biopesticide phosphonate treatments applied alone and in combination with Bravo WS suppressed foliar disease progress significantly when compared to the Aliette and control plots. Three soil drench applications of one phosphonate, Biophos, were particularly promising in terms of tuber blight suppression.