Experimental Host and Vector Ranges of the Emerging Maize Yellow Mosaic Polerovirus

Maize yellow mosaic virus (MaYMV) is an emerging polerovirus that has been detected in maize, other cereal crops, and weedy grass species in Asia, Africa, and the Americas. Disease symptoms in maize include prominent leaf tip reddening and stunting. Infection by MaYMV has been reported to reduce plant growth and yields by 10 to 30% in some instances. In this study, an experimental host range for MaYMV among agronomically important cereal crops and common grasses was established. Additional aphid species were assessed as potential vectors for MaYMV, and their transmission efficiencies were determined. Here, we report oats, foxtail millet, barley, and rye as new experimental cereal crop hosts of MaYMV in addition to confirming the previously reported hosts of corn, sorghum, wheat, and broom millet. Four of the nine other grass species evaluated were also identified as suitable experimental hosts for MaYMV: ryegrass, switchgrass, green foxtail, and sand love grass. Interestingly, no visible symptoms were present in any of the infected hosts besides the susceptible maize control. Vector range studies identified the greenbug aphid Schizaphis graminum as a new vector of MaYMV, though transmission efficiency was lower than the previously reported Rhopalosiphum maidis vector and similar to the other known aphid vector R. padi. Given MaYMV's global ubiquity, ability to evade detection, and broad host range, further characterization of yield impacts and identification of viable control strategies are desirable.