JUST PUBLISHED: Fungicide performance against powdery mildew, 2021

Figure 1. Greenhouse-grown strawberry leaf showing a few powdery mildew lesions.

The results of two powdery mildew fungicide trials conducted in 2021 were just published in Plant Disease Management Reports. In these trials, 17 unique products were evaluated for performance against powdery mildew under greenhouse conditions (Fig. 1). Weekly disease incidence and severity was assessed one day prior to each of five fungicide applications and two weeks after the final application. Disease severity was based on the percent of the upper and lower leaf surfaces covered by visible mycelial growth of each fully emerged trifoliate leaf one week after the final fungicide application (Fig. 2). The full reports can be accessed here (Spring Trial, Summer Trial).

Figure 1. Results from two fungicide evaluation trials against powdery mildew conducted in 2021. Applications for spring trail (left) began on 18 May and 7 Jul for summer trial (right). Data was subject to ANOVA and Fishers LSD mean separation. Error bars represent standard error of the mean. Means that do not share the same letter are significantly different (α=0.05).
/ = Weekly rotation; + = tank mix; ♦ = Biological; ᴺᴿ = Not registered; M-P+K-M-O+K-M =Microthiol Disperss (5 lb/A) – PerCarb + Kinetic – Microthiol Disperss (5 lb/A) – Oxidate + Kinetic – Microthiol Disperss (5 lb/A)