Integrated Management of Powdery Mildew of Mango in Egypt

• Nofal M.A., Wafaa M. Haggag
• Department of Plant Pathology, Davison of Agricultural Research and Biology, National Research Center, Dokki, Cairo, Egypt.
• Email: mkelany@link.net
• Tel.: +002023371362; fax: 002-02-3370931
• The Third International Conference onIPM Role in Integrated Crop management and Impacts on Environment and Agricultural Products. 26-29 November 2005, Giza, Egypt.

Abstract

Powdery mildew caused by Oidium mangiferae, is the most important disease of mango. Field surveys of five cultivars in five Governorates, revealed that incidence of infection was higher on Alphonso and Seddek than on Zebda, Hendi Besenara and Ewise cultivars. The highest disease incidence was recorded in El-Behera Governorate. Various environmentally friendly natural compounds as alternatives to chemical fungicides were evaluated for their efficacy on controlling mango powdery mildew in an integrated pest management system. The tested natural compounds were the biological control agents (BCAs) (Verticillium lecanii, Bacillus subtilis and Tilletiopsis minor); mineral salt (phosphate solutions, KH2PO4); antitranspirant (kaolin) and antioxidant (ascorbic acid) applied independently or mixtures. Application of BCAs , kaolin alone and / or in combination with KH2PO4 in vitro to mango leaves before inoculation with Oidium mangiferae markedly decreased conidial germination and leaf infection. The largest decrease was obtained with combined treatments. Field trials were carried out during 2003 and 2004 in El-Noubaria using Alphonso and Seddek cultivars naturally infected by powdery mildew. Each treatment, applied at 15 d intervals effectively controlled O. mangiferae on blossom clusters and fruit set. BCAs and kaolin treatments were superior in reducing powdery mildew infection. Blossom clusters and fruit set infection were inhibited by using a mixture of BCAs with kaolin and or KH2PO4. Other tested compounds, such as ascorbic acid as a single treatment or in combination with other compounds showed some effectiveness in reducing disease severity. Mixtures of all four natural compounds were more effective in significantly reducing powdery mildew severity and conidia counts on blossom clusters and fruit set and increasing fruit set than mixtures of two or three or single applications. In addition, mixtures of these compounds resulted in higher yields on trees of both cultivars than application of the compounds singly. BCAs, mineral salts, antitranspirant and antioxidant in combinations could be used in an integrated pest management system to control powdery mildew in mango trees.