Efficacy of fungicides on Hymenoscyphus fraxineus and their potential for control of ash dieback in forest nurseries

Abstract

Summary Twenty‐six commercial formulations of fungicides at six concentrations were evaluated in vitro for their efficacy on mycelial growth of Hymenoscyphus fraxineus (anamorph Chalara fraxinea). The results are presented as EC50, EC90 and minimal inhibitory concentration values; the comparisons with the recommended application concentrations showed that 10 of the 26 fungicides were highly effective in their ability to inhibit the mycelial growth of the pathogen. The eight most effective fungicides identified based on multiple comparisons analysis were azoxystrobin, bitertanol, captan (in two‐component preparation with trifloxystrobin), difenoconazole, kresoxim‐methyl, spiroxamine (in multicomponent preparation with tebuconazole and triadimenol), tebuconazole and trifloxystrobin. Azoxystrobin, difenoconazole, kresoxim‐methyl, mancozeb, myclobutanil, pyrimethanil, tebuconazole and trifloxystrobin were selected to verify their effectiveness in in planta tests. During two field tests in nurseries, it was found out that tebuconazole (triazole), trifloxystrobin and kresoxim‐methyl (strobilurins) and mancozeb (dithiocarbamate) were significantly effective against H. fraxineus. The best results were gained with tebuconazole, when mean percentage of diseased saplings was 16.3%, whereas in the control, it was 63.6%. The combination and alternation of fungicides from the triazole, strobilurine and dithiocarbamate chemical groups should be an effective tool for protecting ash saplings in forest nurseries. Moreover, exact timing of the treatment reflecting rainfall and development of first symptoms in the foliage will be also important.

Potential Applications and Antifungal Activities of Engineered Nanomaterials against Gray Mold Disease Agent Botrytis cinerea on Rose Petals

“…In vitro and in planta assays are two major methods for evaluating the effects of potential antifungal agents, such as metabolites ( Lecomte et al, 2012 ; Zhang et al, 2013 ), commercial fungicides ( Dal Maso et al, 2014 ), biological control agents ( Pane and Zaccardelli, 2015 ; Yao et al, 2016 ), and plant essential oils ( Hong et al, 2015 ; Varo et al, 2017 ). Compared with in vitro assays, in planta experiments have more practical significance and are widely used in screening efficient fungicides and assessing antifungal activities ( Dal Maso et al, 2014 ; Hrabětová et al, 2017 ; Varo et al, 2017 ). In our study, the inhibitory effects of NPs on fungi were determined on detached rose petals after 72 h.…”

Complex associations between cross‐kingdom microbial endophytes and host genotype in ash dieback disease dynamics

“…A range of silvicultural and arboricultural management practices have been suggested for ash dieback mitigation, such as increasing local tree species diversity, removing infected tissue and/or autumn leaf fall, reducing tree density and applying fungicides (Hrabětová, Černý, Zahradník, & Havrdová, ; Skovsgaard et al, ). However, such methods may be expensive, labour‐intensive and damaging to the environment.…”

Ash dieback: From Asia to Europe

“…Fungicides containing triazole and quinone slow the growth of H . fraxineus in living ash (Hrabětová et al., 2017; Skovsgaard et al., 2017). Leaf litter could also be treated, preventing the production of ascospores, but with negative environmental consequences for affected non‐target fungal species (Skovsgaard et al., 2017).…”