ABSTRACT

The foliar diseases caused by Ramularia areola, Alternaria sp., Stemphylium spp., Cercospora sp. and Xanthomonas campestris pv. malvacearum has increased in importance in Brazil. This has been attributed to the use of new cotton cultivars, which are susceptible to all these pathogens. The purpose of this test was to examine the severity of leaf diseases on Deltapine ITA- 90 and DeltaOpal cultivars and chemical control of ramularia leaf spot on cotton in Brazil. Both cultivars were susceptible to the leaf diseases, but DeltaOpal was less affected by ramularia leaf spot (RLS) and bacterial blight. All the tested fungicides had reduced significantly the RLS severity in relation to the untreated. The fungicides Flint 500 WG + Tilt, Flint 500 WG + Folicur e Priori + Nimbus stood out, providing 100% of control of RLS after 3 applications.