A Novel Plant Resistance Inducer for the Protection of European Ash (Fraxinus excelsior L.) against Hymenoscyphus fraxineus—Preliminary Studies

Krzysztof Turczański,Marta Bełka,Marcin Smiglak,Rafal Kukawka,Maciej Spychalski

doi:10.3390/f12081072

Krzysztof Turczański, Marta Bełka + Show 3 more

Open Access

https://doi.org/10.3390/f12081072

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Abstract

Ash tree disease is caused by an ascomycete fungus Hymenoscyphus fraxineus, which first emerged in 1992, eastern Poland. Site factors, genetic predispositions, and resistance to the pathogen have not been fully described yet. The general aim of the study undertaken was to check the effect of using a new active substance representing benzothiadiazoles, a BTH derivative, namely, N-methyl-N-methoxyamide-7-carboxybenzo(1.2.3)thiadiazole (BTHWA), on ash saplings. A total of 41 ash saplings, aged three to five years, were subjected to this experiment in six variants of treatment. The results of the inoculation with H. fraxineus indicated that the treatment with BTHWA resulted in the limitation of the size of necrotic phloem lesions. Although the lesions were detectable in the cross section, the plants showed no visible signs of infection. The results suggest that H. fraxineus development in ash saplings can be slowed down or even completely stopped through triggering plant resistance by BTHWA.

Highlights

Novel diseases, especially when unknown in the particular ecosystem, often cause mortality to newly infected host species
As observed before, and confirmed in this experiment, plants treated with BTHWA in 10 days intervals before and after the inoculation (W1, S1 variants) sealed their wounds (Figure 4)
Our results suggest that BTHWA can trigger the natural defense mechanism in ash saplings

Summary

Introduction

Especially when unknown in the particular ecosystem, often cause mortality to newly infected host species. This can change, for example, the structure of forest communities, including the extinction of the most vulnerable species [1]. European ash dieback (ADB) is one of the examples of native tree species under the attack of an ascomycete fungus H. fraxineus (HF) [2]. Recent studies revealed that the high mortality rate of ash saplings affects both forest nurseries and natural regenerations, even those with low ash regeneration density [7,8]. Each of the impacted host populations may have different susceptibility to ADB, as trees can evolve resistance mechanisms that allow them to defend themselves against pathogens [9].

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