Comparison of Epidemiology of Gray Mold, Anthracnose Fruit Rot, and Powdery Mildew in Day-Neutral Strawberries in Field and High-Tunnel Conditions in Ontario

Abstract

Anthracnose fruit rot (Colletotrichum acutatum), Botrytis gray mold (Botrytis cinerea), and powdery mildew (Podosphaera aphanis) are major fruit diseases affecting strawberries in Ontario, but the epidemiology and management of these diseases in day-neutral strawberries in high-tunnels plantings are not well understood. Incidences of both Botrytis gray mold (BGM) and anthracnose fruit rot (AFR) were very low in tunnel plots, compared to outdoor plots (5-fold lower BGM incidence and 5–20-fold lower AFR incidence); whereas the incidence of powdery mildew (PM) on berries was higher in the tunnel plots compared to outdoor field plots. BGM incidence was observed in the first two harvest weeks and decreased thereafter in the outdoor plots, where as incidence of BGM was negligible in the tunnel plots. The AFR was first observed in the first week of August and the last week of July in 2009 and 2010, respectively, The epidemics of PM increased after the second week of September in both years. In outdoor field plots, Maestro 80 DF and Nova 40 W or Pristine WG provided good control of BGM and AFR. ‘Seascape’ had significantly lower AFR than ‘Albion’; whereas PM incidence was higher in ‘Seascape’. There were significantly higher (P < 0.01) cumulative marketable fruit numbers (1- to 3-fold higher) and marketable fruit yields (2- to 3.5-fold higher) in tunnel plots than outdoor plots in both years.