Gray leaf Spot: A Disease of Global Importance in Maize Production

Macrófitas aquáticas do Município de General Carneiro, Paraná, Brasil

“…As políticas de conservação têm sido baseadas largamente somente na riqueza de espécies. Sugere-se que a variabilidade ambiental e a substituição de espécies também sejam levadas em consideração no delineamento destas políticas (Tockner 1999, Ward et al 1999) e estes componentes da diversidade total devem ser incorporados nas investigações de ambientes aquáticos. …”

Molecular variability in the maize grey leaf spot pathogens in Brazil

“…Together, these practices may have contributed to a build-up of inoculum that led to epidemic. Thus, it appears that the history of occurrence of grey leaf spot in Brazil is similar to that in the U.S., where the pathogen was not regarded as economically important for several years after it was first reported, but became a major pathogen concomitant with incorporation of changes in cultivation (Roane et al, 1974;Latterell and Rossi, 1983;Ward et al, 1999).…”

“…In Brazil, C. zeae-maydis and C. zeina are sympatric in the maizeproducing regions of the country that were sampled. On the other hand, isolates of C. zeae-maydis have not been recovered from Africa (Dunkle and Levy, 2000;Okori et al, 2003;Crous et al, 2006), suggesting that the grey leaf spot pathogen was not introduced into that continent from the U.S. as proposed by Ward et al (1999). Further considerations, such as historical perspective of the occurrence of the disease on both continents and the relatively greater haplotype diversity in the African population, provide convincing evidence that C. zeina was introduced into the U.S. from Africa or from an unidentified source (Dunkle and Levy, 2000).…”

Infection process in resistant and susceptible maize (Zea mays L.) genotypes to Cercospora zeae-maydis (type II)

“…Tehon and Daniels is the most destructive foliar disease of maize worldwide (Ward et al 1999). Yield losses attributed to grey leaf spot have been reported to be variable (Lipps et al 1998) with estimated losses as high as 100% when severe epidemics contribute to increased stalk rot and early senescence (Latterall & Rossi 1983).…”

“…Methods to manage grey leaf spot include conventional tillage that buries crop residues, crop rotation, fungicides, and utilisation of resistant varieties (Ward et al 1999). Fungicides are widely used in maize production (Munkvold et al 2001) but are too expensive for low income-resource poor farmers in the tropics (Menkir & Ayodele 2005).…”