Cover crops can increase lettuce drop
Steven T. Koike, Monterey and Santa Cruz counties
Richard Smith, San Benito County
Louise E. Jackson, Department of Vegetable Crops, UC Davis
Lisa J. Wyland, Department of Vegetable Crops, UC Davis
William E. Chaney, Emeritus, Monterey and Santa Cruz counties
John I. Inman, Monterey and Santa Cruz counties
California Agriculture 51(1):15-18. DOI: 10.3733/ca.v051n01p15.
Although cover crops contribute many benefits to organic and conventional agricultural systems, they may play a significant role in the epidemiology of soil-borne diseases. A 2-year study shows that Sclerotinia minor, which causes lettuce drop disease, is a pathogen of phacelia, lana woollypod vetch and Austrian winter pea cover crops. Greenhouse and field inoculations failed to result in S. minor infections of oilseed radish, barley and fava bean cover crops. It appears these three cover crops can be safely incorporated into lettuce rotations without increasing the occurrence of lettuce drop.
S.T. Koike is Plant Pathology Farm Advisor, Monterey and Santa Cruz counties; R.F. Smith is Small Farms Farm Advisor, San Benito County; L.E. Jackson is Associate Professor and Specialist, Department of Vegetable Crops, UC Davis. L.J. Wyland is Staff Research Associate, Department of Vegetable Crops, UC Davis. W.E. Chaney is Entomology Farm Advisor, Monterey and Santa Cruz counties; J.I. Inman is retired Farm Advisor, Monterey and Santa Cruz counties;
This research was supported by the Sustainable Agriculture Research and Education Program, UC Davis, and by the USDA-EPA A.C.E. Project 91-COOP-1-6590. The authors thank H. Agamalian, Y.-T. Cao, S. Dacuyan, T.G. Gonzales, E.D. Oakes, J. Taylor and M. Vidauri for their assistance, and acknowledge Hartnell College for the use of their farm facility.