Quantification of Yield Losses Due to Anthracnose Stalk Rot on Corn in Brazilian Conditions

Abstract

The anthracnose stalk rot of corn (ASR), caused by Colletotrichum graminicola, is a major disease of this crop and occurs in most Brazilian regions where corn is grown. Despite its widespread occurrence, there are no estimates of the effect of ASR on the yield of corn under the Brazilian conditions. In this study, we evaluated the effect of ASR on corn hybrids yield. Two experiments were conducted (first crop 2007/2008 and second crop, 2009) in areas with a history of occurrence of leaf anthracnose and ASR. Five hybrids were evaluated in the first and second crops: AG1051, BRS 1001, BRS 1010, BRS 1035, P30F80 and BRS 1010, 2B710, P30F80, DKB390, BRS 1035, respectively. At harvest, we evaluated the incidence of plants with anthracnose stalk rot (IPASR), and we selected pairs of healthy and diseased plants to quantify the effect of ASR in the ear weight (EW), grain weight (GW) and the weight of a sample containing 100 kernels (W100). The IPASR was higher in the hybrid BRS 1010 (21.87 and 45.28%, first and second crops, respectively). The EW, GW and W100 were lower in diseased plants in all hybrids. The mean weight loss in the first season was EW 29.03%, GW 27.83% and W100 17.08%, and the second season was EW 27.75%, GW 25.60% and W100 16.99%. The most affected hybrids with weight loss in the first crop were AG1051 (EW 34.31%, GW 33.05%, W100 19.96%) and BRS 1035 (EW 34.74%, GW 34.65%, W100 22.31%). In the second crop, were P30F80 (EW 30.72%, GW 30.92%, W100 19.24%), DKB390 (EW 30.61%, GW 29.81%) and 2B710 (W100 19.27%). Corn yield was strongly affected by ASR.

Validação de escala diagramática para quantificação da severidade da antracnose do colmo do milho

“…Wils é uma das doenças mais importantes na cultura do milho em vários países, causando acamamento das plantas, redução na produção e qualidade dos grãos (BERGSTROM & NICHOLSON, 1999;COTA et al, 2012;MATIELLO et al, 2013). Os sintomas da antracnose do colmo são mais visíveis após o florescimento das plantas de milho, porém o processo infeccioso inicia-se pelos propágulos provenientes das lesões foliares ou daqueles presentes em restos culturais.…”

Identification of sources of resistance to anthracnose stalk rot in maize

“…The red mark is a kind of background to resistance; though there are some red susceptible genotypes. The simple hybrid 2B710 has an effective resistance level and showed red pigmentation in the stalk surface and leaves veins, which appears in some genotypes due to the production of carotenoids and flavonoids (GARDINGO, 2008;COSTA et al, 2010b;COTA et al, 2010;COTA et al, 2012;CARVALHO et al, 2013). This genotype has been used as a positive control in studies investigating anthracnose stalk rot resistance, as well as for genotype selection in germplasm banks; in addition, this hybrid has shown good agronomic features in many studies (COTA et al, 2012;CARVALHO et al, 2013;ZUCARELI et al, 2013, COSTA et al, 2014.…”

“…It is the principal disease of maize, capable of causing plant lodging, early plant death, and losses of approximately 35% in grain weight (BERGSTROM & NICHOLSON, 1999;DENTI & REIS, 2003;PALAVERSIC et al, 2009;COSTA et al, 2010a;JIRAK-PETERSON & ESKER, 2011;COTA et al, 2012 have a wet aspect and are brown to reddish in color, while old lesions are typically dark brown to black in color. In the stalk tissues, it is possible to see typical dark-brown coloring, which corresponds to necrotic lesions that lead to plant lodging and early death (BERGSTROM & NICHOLSON, 1999;COTA et al, 2012). This disease is one of the most important in maize crops and is very hard to control necessitating the use of integrated management practices.…”

Colletotrichum graminicola from leaves or stalks are similarly aggressive in cross-tissue inoculation of five maize hybrids

“…Nicholson 1999; Costa et al 2010aCosta et al , 2014Cota et al 2012). In addition to cultural methods, studies have reported the potential to use host plant resistance to manage ALB or ASR (Badu-Apraku et al 1987;Toman and White 1993;Coêlho et al 2001;Palaversic et al 2009;Frey et al 2011;Chung et al 2011;Matiello et al 2012).…”

“…Each experiment used twenty C. graminicola isolates, and was defined by a single commercial hybrid varying in susceptibility to the anthracnoses. The hybrid BRS1010 is considered susceptible to anthracnose (Costa et al 2010b;Cota et al (Costa et al 2010b(Costa et al , 2014Cota et al 2010;Carvalho et al 2013), 2B707 is considered resistant to stalk disease, and P30F35 and P3862 are considered moderately resistant to stalk disease (Cruz et al 2013).…”