the Symposium on Wheats for More Tropical Environments - cimmyt

200Interval between spraying.The fourth important aspect of <strong>the</strong>spraying schedule is <strong>the</strong> intervalbetween fungicidal applications.Experience indicates that <strong>the</strong> intervalshould be about 15 days. regardless of<strong>the</strong> kind of fungicide used. With specialreference to spot blotch. whenprotectant fungicides like Maneb orMancozeb are used. and when wea<strong>the</strong>rconditions are very favorable to <strong>the</strong>disease. <strong>the</strong> interval should be reducedto 10 to 12 days.Maneb or Mancozeb are broad-spectrumfungicides and. as a rule. should beused for complex disease situations.Besides being very economical. <strong>the</strong>iruse minimizes <strong>the</strong> danger of creatingresistant strains of <strong>the</strong> pathogen.Although <strong>the</strong> establishment ofanappropriate spraying schedule is ofutmost importance before any controlmeasure is employed. no hard and fastrules can be laid out. On-<strong>the</strong>-spotmodifications are quite often necessary.and <strong>the</strong> wheat variety. wea<strong>the</strong>rconditions and <strong>the</strong> intensity of <strong>the</strong>disease must be considered.References1. Mehta. Y.R.. S. Igarashi andN.R.X. Nazareno. 1978. Urn novocriterio para avaliar fungicidascontra doenccas foliares do trigo.Summa Phytopathologica 4:55-66.2. Zadoks. J.C.. T.T. Chang andC.F. Konzak. 1974. A decimal codefor <strong>the</strong> growth stages of cereal.Eucarpia Bulletin 7.