Crop Loss Assessment for Flue-Cured Tobacco Cultivars Infected with Tobacco Mosaic Virus. C. S. Johnson, Graduate Assistant, Department of Plant Pathology, North Carolina State University, Raleigh 27650. C. E. Main, Professor, and G. V. Gooding, Jr., Professor, Department of Plant Pathology, North Carolina State University, Raleigh 27650. Plant Dis. 67:881-885. Accepted for publication 21 January 1983. Copyright 1983 American Phytopathological Society. DOI: 10.1094/PD-67-881.

Effects of inoculation date and incidence (percent plants infected) of tobacco mosaic virus (TMV) on yield, quality, and value of flue-cured tobacco were studied at two locations in North Carolina for 2 yr. Inoculation of seven susceptible cultivars with TMV in 1980 resulted in significant losses, which averaged 13, 16, and 16% in yield, grade index, and value, respectively. There were no differences in effects of inoculation at 7, 35, 49, or 63 days after transplanting either year of the investigation. Inoculation of 15, 30, 60, or 100% of the plants per plot with TMV in 1981 produced reductions of 7, 10, 17, and 30% in yield and 7, 14, 21, and 36% in value. No differences in leaf area and grade index of the tobacco were associated with the different incidences of the virus. Regression models were developed for estimating losses in flue-cured tobacco yield and value from TMV incidence data obtained through surveys conducted across North Carolina.