stunting disease, not only in the Corn Belt, but in the southeastern US as well. The distribution of MCDV overlaps that of its native vector, Graminella nigrifrons, and its over-wintering host, the introduced, perennial weed, johnsongrass. Johnsongrass also is the primary alternate host for MDMV. Fortunately, the northerly distribution of johnsongrass is limited to the southern fringe of the Corn Belt; the leafhopper and aphid vectors migrate to as far north as Canada. Neither virus has ever spread to the heart of the Corn Belt. Control of MCDV and MDMV has been principally by the development of virus tolerant and or resistant varieties and management of johnsongrass. These control measures proved timely and highly successful in returning maize in infested regions to pre-disease production levels.
Spin-off from the formation of the maize virus team in Wooster and its collaboration with workers from more than 20 states has been multifold. Among the discoveries by the team in its first decade was uncovering another complex of corn stunting pathogens endemic to Texas, Florida, and other Gulf Coast states. Causal agents are the corn stunt spiroplasma, the maize bushy stunt phytoplasma, and the maize rayado fino virus. All three are transmitted by the corn leafhopper, Dalbulus maidis. Also discovered were the maize mosaic and the maize stripe viruses in these same Gulf Coast States; both are obligately transmitted by the corn delphacid, Peregrinus maidis. The beetle vector of the maize chlorotic mottle virus, a virus introduced into Nebraska and Kansas from the Andes was also discovered. So too were the eriophyid mite-borne wheat streak mosaic and wheat spot mosaic viruses in maize as well as the mite-induced phytotoxin, the cause of kernel red streak disease in the Great Lakes region. Information derived from the etiology of these maize pathogens provided researchers elsewhere (in the United States and internationally) with new and better tools to detect and manage maize diseases.
The OSU/USDA maize virus team on the Wooster campus remains as the foremost center, both nationally and internationally, for the study of maize virus diseases. There is a new generation of scientists who have replaced retired members of the original team. These scientists have brought new skills, especially in the molecular arena, to bear upon the discovery, characterization, and management of vector-borne maize pathogens. Dozens of graduate students, post doctoral scientists, visiting faculty and other researchers have been educated, trained or have advanced their careers working with the maize virus team. It should be noted that several “alumni” are now investigating vector-borne citrus pathogens, including HLB.
What lessons learned from the experiences of the maize virus team is relevant to the strategies for the study of HLB? Many factors contributed to the successes of the maize virus team but the following were most critical.
The team was formed by recruiting young scientists who were trained in the varied disciplines required for solving the problems associated with vector-borne plant pathogens. Just as important was that they joined forces with experienced faculty familiar with maize diseases and corn breeding in the Corn Belt states.
Members of the team were committed to a common goal. All were located on the same campus, many in the same suite of offices and research laboratories. The OSU and USDA scientists, their staff, and the students interacted daily, freely exchanging information and utilizing each other’s equipment and resources. Team members formed and, as circumstances dictated, reformed flexible units of two or more specialists to tackle specific problems. Team members met frequently with regularly scheduled meetings and seminars.