Excerpted from the
Edited by Krishna V. Subbarao, R. Michael Davis, Robert L. Gilbertson, and Richard N. Raid
Reproduced, by permission, from Hayes, R. J. 2017. Lettuce production. Pages 1-6 in: Compendium of Lettuce Diseases and Pests, 2nd ed. K. V. Subbarao et al., eds. American Phytopathological Society, St. Paul, MN.