Integrated crop management : late blight

CALDIZ, D.; ADRIANA BALBINA ANDREU

Augustine, Florida, USA

Conferencia; AgCON 2005, 5th McCain World Class Agriculture Conference; 2005

McCain Food

The Late blight caused by the oomycete Phytophthora infestans is considered the most important disease of potato crops worldwide. Yield reductions are caused by premature foliage infections and tuber infections. Update information on Late blight susceptibility of commercial cultivars is needed by crop managers and growers in order to optimize a successful use of integrated crop management strategies. Laboratory, greenhouse, and field test showed that cv. Shepody is highly susceptible to the most agressive Argentinian isolate, while cvs. Kennebec and Russet Burbank are medium susceptible, Ranger Russet and Santana (foliage) low susceptible and Innovator is resistant at foliage and tuber level. Tubers of Kennebec and Santana resulted more susceptible than their foliage. Seed treatments with contact fungicides (propineb, mancozeb) protect the healthy tubers of susceptible cultivars from infections during the handling process. Early foliar applications of compounds with basipetal translocation, fosfites (Alliete) or aminobutiric acid (BABA), enhance plant resistance (SAR) at tuber level during harvest and storage. A high level of phytoalexin and phenol compounds were found in these tubers, hence, these compounds can be considered molecular markers of the defense response. All these results are part of an integrated Late blight management approach that is being carried out in Argentina.