Biology and control of maize chlorotic mottle virus.
Maize chlorotic mottle virus (MCMV) was first recovered from maize in Kansas in 1976 and is now known to be endemic in the north-central region of the state and in south-central Nebraska; it has also been found once in the High Plains of Texas and Brazil, and is known to be endemic in Peru. In Kansas, the disease it produces has caused heavy crop losses, and the virus is found in association with maize dwarf mosaic virus and wheat streak mosaic virus. In preliminary experiments to determine the mode of transmission, laboratory-reared larvae of Diabrotica undecimpunctata Mannh. that fed and tunnelled in previously dried and then rehydrated maize roots transmitted the virus in at least 1 experiment. Maize trash collected from a diseased field also contained infective MCMV. It appears possible, therefore, that overwintering larvae of this rootworm acquire the virus while foraging on diseased plants and later transmit it to new plants. The virus was not seed-borne in weed or maize plants and was not transmitted transovarially in eggs of D. undecimpunctata. The disease was effectively controlled by crop rotation, but not by other cultural practices, including autumn ploughing.