Effect of Film-Forming Compounds on the Development of Leaf Rust on Wheat Seedlings. Judith Zekaria- Oren, Department of Botany, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 69978, Israel. Z. Eyal, and O. Ziv. Department of Botany, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 69978, Israel, and Agricultural Research Organization (ARO), The Volcani Center, Bet Dagan 50250, Israel. Plant Dis. 75:231-234. Accepted for publication 9 July 1990. Copyright 1991 The American Phytopathological Society. DOI: 10.1094/PD-75-0231.

The effect of film-forming antitranspirants and glues on the development of leaf rust (caused by Puccinia recondita f. sp. tritici) was assessed on wheat seedlings (Triticum aestivum ‘Ceeon’). When applied before rust inoculation, the compounds Bio-Film, Folicote, and Vapor Gard markedly reduced the number of pustules per square centimeter. Postinoculation application had a significantly smaller effect on suppression of rust development. The efficacy of each compound depended on its concentration. More than 80% suppression of rust development was achieved by application of 0.5% Bio-Film, whereas equivalent suppression was obtained with either 2% Folicote or Vapor Gard. Although germination of urediniospores was not affected, the number of appressoria formed was reduced by 20% with Folicote and by more than 70% with either Bio-Film or Vapor Gard. Only 30% of the appressoria were formed above the stomata. The results suggest that film-forming compounds alter the topography of the leaf surface, thus interfering with adhesion of the germ tube and recognition of penetration sites.