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Wind Dispersal of Conidia of Cercospora beticola. J. S. Lawrence, Research Assistant, Department of Plant Pathology, University of Nebraska, Lincoln 68503, Present address of author: Department of Plant Pathology, University of Hawaii, Honolulu 96822; D. S. Meredith, Associate Professor, Department of Plant Pathology, University of Nebraska, Lincoln 68503, Present address of author: Department of Plant Pathology, University of Hawaii, Honolulu 96822. Phytopathology 60:1076-1078. Accepted for publication 17 February 1970. DOI: 10.1094/Phyto-60-1076.

In spore-trapping studies in Nebraska, conidia of Cercospora beticola were freely airborne, and formed a regular component of the air-spora over infected red beets (Beta vulgaris). Airborne conidia of C. beticola displayed a well-defined diurnal periodicity with a peak concn at 1000 hr; few conidia were trapped between 1600 and 0600 hr. Daily increases in conidium concn coincided with the time when wind velocity and temp were increasing and relative humidity was decreasing. Conidia were detected in the atmosphere on all days, but concn fluctuated greatly from day to day. Greatest numbers of conidia were trapped on warm, dry days preceded by a period of rain or overnight dew. High concn were also recorded during periods of high atmospheric turbulence. Very few conidia were detected in the air during rainfall or while the beet leaves were still wet.