Comparison of Epidemics of Botrytis Fruit Rot and Powdery Mildew of Strawberry in Large Plastic Tunnel and Field Production Systems.

Epidemics of Botrytis fruit rot (Botrytis cinerea) and powdery mildew (Sphaerotheca macularis f. sp. fragariae) in annual strawberry were compared in large plastic tunnel and field production systems during the 1998-99 and 1999-2000 seasons. Treatments were factorial combinations of two main plots (field and tunnel) and four subplots, including combinations of two cultivars (Camarosa and Sweet Charlie) and two captan schedules arranged in a split-plot design with three replications. The mean incidence of Botrytis fruit rot was 88 to 94% lower in tunnels than in the field. The incidence of Botrytis fruit rot for the untreated control in tunnels was less than 2%, which was 89% lower than that of the 7-day captan schedule in the field. This indicates that Botrytis fruit rot can be controlled effectively without fungicides in a tunnel cultural system. Powdery mildew was severe on susceptible cultivar Camarosa in tunnels. Early season yields of cultivar Sweet Charlie were significantly higher in tunnels than in the field. Shorter periods of leaf wetness and higher temperatures in tunnels may have contributed to a lower incidence of Botrytis fruit rot and a higher incidence of powdery mildew on fruit in tunnels compared with open field plots.