Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/25/2002
Publication Date: 9/1/2002
Citation: MILLS, D.J., COFFMAN, C.B., TEASDALE, J.R., EVERTS, K.L., LYDON, J., ANDERSON, J.D. FOLIAR DISEASE IN FRESH MARKET TOMATO GROWN IN DIFFERING BED STRATEGIES AND FUNGICIDE SPRAY PROGRAMS. PLANT DISEASE. 2002. Interpretive Summary: Fresh market tomatoes generally are produced using polyethylene mulch-based systems, which require substantial fungicide input to maintain acceptable productivity levels. With the objective of reducing fungicide input, foliar disease in fresh market tomato was assessed under four soil mulch treatments and three fungicide treatments. The soil mulch treatments in this three-year study were bare ground, black polyethylene, dairy manure compost, and a cover crop, hairy vetch. The fungicide treatments were no fungicide, weekly fungicide application, and a fungicide application program scheduled by the foliar disease-forecasting model, TOMCAST. Without fungicide, disease severity and defoliation were lower in hairy vetch versus bare ground or compost in all years. Disease severity and defoliation were lower in black polyethylene versus bare ground or compost in two of three years. Disease severity and defoliation were lower rin hairy vetch versus black polyethylene in one and two years, respectively. With fungicide, there were no differences in disease severity or defoliation among the soil mulch treatments. Foliar disease and defoliation were suppressed equally well under the TOMCAST and weekly spray schedules, even though TOMCAST recommended 40 to 50% fewer sprays than the weekly spray schedule. These results show that a reduced-input production system based on hairy vetch mulch and the TOMCAST spray program can exhibit similar or reduced levels of foliar disease and defoliation compared to a higher-input system predicated on black polyethylene mulch and weekly fungicide sprays.
Technical Abstract: A three-year field study was conducted in central Maryland to quantify foliar disease in fresh market tomato grown under soil mulch treatments and fungicide application schedules. The soil mulch treatments included bare ground, bare ground amended with dairy manure compost, black polyethylene, and a hairy vetch cover crop. The fungicide treatments included no fungicide, weekly application, and application scheduled using TOMCAST, a disease-forecasting model. Without fungicide, early blight and septoria leaf spot severity and defoliation were lower in hairy vetch versus bare ground or compost in all years. Disease severity and defoliation were lower in black polyethylene versus bare ground or compost in two of three years. Early blight severity and defoliation were lower in hairy vetch versus black polyethylene in one and two years, respectively. Septoria leaf spot severity was similar in hairy vetch and black polyethylene. With hfungicide, there were no disease severity or defoliation differences among mulch treatments. Fungicide applied according to the TOMCAST and weekly spray schedules suppressed foliar disease and defoliation equally. TOMCAST use reduced fungicide input 40 to 50% compared to the weekly program.