Powdery mildew (PM) is a significant fungal disease in controlled environment horticulture (CEH). PM damages are increasingly being reported in fungicide-untreated and late planted open fields. Both field and protected systems in the major production regions of the world are facing heightened challenges due to the increasing disease occurrences. While PM has been efficiently managed by spraying chemical fungicides in field production, frequent use increases the risk of resistance development in pathogens. Additionally, fungicidal sprays may not be feasible to all CEH farms due to infrastructural restrictions or organic mode of production. The expansion of CEH production in Texas has created opportunities to extend strawberry cultivation from coastal regions to inland areas. However, PM management needs to be addressed given the conducive growing conditions in CEH. To study the prevalence of the disease, we evaluated 24 and 12 strawberry accessions arranged in a completely randomized design in two replications in the greenhouse and growth room conditions, respectively. In the absence of fungicide treatments, natural infections led to PM development within two weeks after transplanting. Disease ratings revealed incidence rates of 72% in the growth chamber and 49% in the greenhouse. The correlation between the two replications was 0.88 and 0.87, respectively. Accessions that exhibited little to no PM symptoms may be valuable for understanding host resistance mechanisms and could be utilized in breeding resistant cultivars in the future.
