Effects of plant spacing and cultivar on incidence of Botrytis fruit rot in annual strawberry

The effects of within-row plant spacing and cultivar on the incidence of Bo trytis fruit rot (Botrytis cinerea) and marketable yield of annual strawber ry were evaluated during the 1997-98 and 1998-99 seasons. Three cultivars ( Camarosa, Rosa Linda, and Sweet Charlie) and four plant spacings (23, 30, 3 8, and 46 cm) were evaluated. Marketable yield and the incidence of Botryti s fruit rot were determined twice weekly. Cultivar and spacing effects were analyzed for three periods each season (early, late, and whole season). In 1997-98, spacing effects were observed on weekly incidence of Botrytis rot for the late period (P = 0.0925) and on cumulative incidence for the whole season period (P = 0.0795). Further analysis of the late and whole season periods revealed a spacing effect for Camarosa (P = 0.0102). Spacing also h ad a dramatic effect on cumulative and weekly Botrytis incidence for the la te and whole season periods during the 1998-99 season (P less than or equal to 0.0014), when narrower spacings had higher incidence of Botrytis than w ider spacings. Marketable yields were higher at narrower spacings during th e early period for both seasons. Whole season marketable yields were also h igher at the narrower spacings despite higher incidence of Botrytis. There were significant differences in susceptibility among cultivars.