Maize dwarf mosaic virus (MDMV) is a pathogenic plant virus of the family Potyviridae. Depending on the corn plant’s growth stage, the virus can have severe implications to the corn plant’s development which can also result in economic consequences to the producer of the crop. Importance Maize (Zea mays) is a major cereal crop; it is third behind rice and wheat in production. An average of 380 million tons are produced annually by 53 countries. Maize is the most widely grown crop ranging from tropical areas with altitudes over 3000 m to temperate areas extending as far north as the 65th latitude. MDMV is the most serious virus of sweet corn. If corn plants are infected with MDMV, ear formation and development are slowed leading to grain yield loss. The damage from MDMV can cause the halting of ear formation and development, ultimately leading to the production of barren ears and direct yield loss. There can be losses of up to 42% on early planted field corn. If corn is planted late MDMV can cause 75% or more loss on inbred and hybrid varieties. The number of ears per plant is reduced by MDMV infection and the fresh weight of these ears can be reduced by 30%. Pathogenesis MDMV is caused by various strains. There are five strains A, C, D, E, and F. They differ in biological, serological, and nucleotide sequences. The vector for MDMV transmission is aphids. There are 15 aphid species that can non-persistently transmit MDMV. The aphids mainly feed on the family Poaceae. MDMV overwinters in alternate hosts. These hosts range is sorghum, maize, and Johnson grass. Symptoms appear six weeks after aphids feed and transmit the virus. The aphid acquires the virus within seconds of feeding on an infected plant, either maize, Johnson grass, or sorghum. There is no latent period for transmission to new host plants. After acquiring MDMV an aphid is able to transmit the virus within 15–30 minutes. Aphids do not retain MDMV after molting. The virus can also be spread through the seed or mechanically by leaf rubbing of Johnson grass and sorghum. MDMV in the field is not typically transmitted by seed or mechanically, it is more prevalent in greenhouses. Depending on the hybrid, most maize plants will show higher rates of disease when infected earlier in the growing stage. The pathogen itself is a flexuous, rod-shaped virus measuring 12