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

Abstract

Abstract The anthracnose stalk rot of corn ( ASR ), caused by C olletotrichum 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 B razilian 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: AG 1051, BRS 1001, BRS 1010, BRS 1035, P 30 F 80 and BRS 1010, 2 B 710, P 30 F 80, DKB 390, 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 ( W 100). The IPASR was higher in the hybrid BRS 1010 (21.87 and 45.28%, first and second crops, respectively). The EW , GW and W 100 were lower in diseased plants in all hybrids. The mean weight loss in the first season was EW 29.03%, GW 27.83% and W 100 17.08%, and the second season was EW 27.75%, GW 25.60% and W 100 16.99%. The most affected hybrids with weight loss in the first crop were AG 1051 ( EW 34.31%, GW 33.05%, W 100 19.96%) and BRS 1035 ( EW 34.74%, GW 34.65%, W 100 22.31%). In the second crop, were P 30 F 80 ( EW 30.72%, GW 30.92%, W 100 19.24%), DKB 390 ( EW 30.61%, GW 29.81%) and 2 B 710 ( W 100 19.27%). Corn yield was strongly affected by ASR .