Abstract
Three corn hybrids (Zea mays L. A619 .times. A632, B73 .times. FR16 and Mo17 .times. B73) were planted in replicated blocks and spray-inoculated at 3-, 7- and 14-leaf stages. Inocula consisted of maize chlorotic mottle virus (MCMV), maize dwarf mosaic virus strain A (MDMV-A) and a combination of the 2. Single virus infections caused systemic mottle or mosaic leaf patterns and reduced grain yields. Symptoms on all hybrids inoculated with the virus combination at 3- and/or 7-leaf stages consisted of a systemic chlorotic mottle, tissue necrosis beginning at leaf margins and progressing to the mid-vein, stunting, and premature death of plants. Chlorosis and necrosis of terminal leaves developed in plants at the 14-leaf stage inoculated with MCMV and MCMV plus MDMV-A. Early virus infections significantly reduced corn yields; losses were heaviest on plants receiving the virus combination.