EFFICACY OF METALAXYL, FOSETYL-ALUMINUM, AND STRAW MULCH FOR CONTROL OF STRAWBERRY LEATHER ROT CAUSED BY PHYTOPHTHORA-CACTORUM

Chemical and cultural controls for strawberry leather rot, caused by P hytophthora cactorum, were compared in replicated plots on a commercia l farm near Wooster, Ohio. Straw mulch, applied uniformly for winter p rotection, was removed in early spring from between the rows of all ch eck and fungicide treatment plots. Supplemental straw mulch was applie d to other plots to achieve a level of approximately 9 t/ha. Overhead irrigation, which caused the soil to puddle, was provided on alternate days during rain-free periods to promote disease development (58, 66, and 73% incidence in check plots for 1993, 1994, and 1995, respective ly). Foliar sprays of fosetyl-Al, applied weekly from bloom through pr eharvest at rates (a.i.) of 2.24 and 4.48 kg/ha, provided 88 to 96% co ntrol, with no significant difference between fungicide rates. Metalax yl (1.17 kg/ha), applied either once or twice as a soil drench from ea rly growth through fruit set, provided 82 to 94% control. Straw mulch alone provided 95 to 99% control. Thus, straw mulch between the rows w as equally or more effective than fungicides for controlling leather r ot.