Each year, downy mildew caused by Bremia lactucae occurs in lettuce-producing regions of Quebec and Ontario. Trials were conducted to determine if the disease could be managed with fewer fungicide applications, using disease forecasting. Disease-forecasting programs designed to time the application of fungicide sprays were evaluated for control of downy mildew of lettuce in 1997 and 1998 at 9 field sites. Disease forecasting was based on lesion development following a recorded sporulation-infection period (SIP), with leaf wetness between 3:00 AM and 10:00 AM and temperature between 5 and 20 °C. Presymptom sprays with the protectant fungicide mancozeb were applied before lesions were expected; they were based on 110 accumulated degree-days following a SIP, but not within 7 days of a previous spray. Post-latent-period sprays with the systemic fungicide metalaxyl-M in combination with mancozeb were applied after forecasted lesion development; they were based on 135 accumulated degree-days, but not within 14 days of a previous spray. The effects of forecasted sprays were compared with those of weekly applications of mancozeb and with those of metalaxyl-M or metalaxyl applied in furrow at the time of seeding or transplanting. Downy mildew developed at 7 of the 9 sites. The number of SIPs recorded at all sites ranged from 7 to 17. In 8 of the 9 sites, there were fewer mancozeb applications with the presymptom program than with the weekly sprays, that is a reduction of one, two, and three sprays at six, one, and one sites, respectively. This resulted in a 16%–60% reduction in applied fungicide. When metalaxyl-M plus mancozeb was applied according to the post-latent-period forecast, one or two sprays were required, that is a reduction of two, three, and four applications at four, three, and two sites, respectively, compared with the weekly application of mancozeb alone. Metalaxyl-M or metalaxyl applied in furrow provided control for 30–40 days after seeding or transplanting. The number of fungicide applications can be reduced with acceptable disease control if a forecasting program is followed.