The Effects of Fungicide, Soil Fumigant, Bio-Organic Fertilizer and Their Combined Application on Chrysanthemum Fusarium Wilt Controlling, Soil Enzyme Activities and Microbial Properties.

Shuang Zhao,Xuena Dong,Weimin Fang,Fadi Chen,Shiping Deng,Jianjun Yao,Aiping Song,Xi Chen

doi:10.3390/molecules21040526

Shuang Zhao, Xuena Dong + Show 6 more

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https://doi.org/10.3390/molecules21040526

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Abstract

Sustained monoculture often leads to a decline in soil quality, in particular to the build-up of pathogen populations, a problem that is conventionally addressed by the use of either fungicide and/or soil fumigation. This practice is no longer considered to be either environmentally sustainable or safe. While the application of organic fertilizer is seen as a means of combating declining soil fertility, it has also been suggested as providing some control over certain soil-borne plant pathogens. Here, a greenhouse comparison was made of the Fusarium wilt control efficacy of various treatments given to a soil in which chrysanthemum had been produced continuously for many years. The treatments comprised the fungicide carbendazim (MBC), the soil fumigant dazomet (DAZ), the incorporation of a Paenibacillus polymyxa SQR21 (P. polymyxa SQR21, fungal antagonist) enhanced bio-organic fertilizer (BOF), and applications of BOF combined with either MBC or DAZ. Data suggest that all the treatments evaluated show good control over Fusarium wilt. The MBC and DAZ treatments were effective in suppressing the disease, but led to significant decrease in urease activity and no enhancement of catalase activity in the rhizosphere soils. BOF including treatments showed significant enhancement in soil enzyme activities and microbial communities compared to the MBC and DAZ, evidenced by differences in bacterial/fungi (B/F) ratios, Shannon–Wiener indexes and urease, catalase and sucrase activities in the rhizosphere soil of chrysanthemum. Of all the treatments evaluated, DAZ/BOF application not only greatly suppressed Fusarium wilt and enhanced soil enzyme activities and microbial communities but also promoted the quality of chrysanthemum obviously. Our findings suggest that combined BOF with DAZ could more effectively control Fusarium wilt disease of chrysanthemum.

Highlights

Chrysanthemum (Chrysanthemum morifolium) is a commercially valuable ornamental species worldwide
Each of the treatments significantly reduced the incidence of Fusarium wilt (Figure 1a) and increased the disease reduction percentage (DRP) (Figure 1b)
Shoot height were greatest for plants exposed to the DAZ + bio-organic fertilizer (BOF) treatment, followed by MBC + BOF and BOF, and lowest in the CK treatment (Table 1)

Summary

Introduction

Chrysanthemum (Chrysanthemum morifolium) is a commercially valuable ornamental species worldwide. Molecules 2016, 21, 526 production of chrysanthemum. As for most crop species, long-term continuous monoculture-based production results in serious continuous cropping obstacles of the chrysanthemum [1,2]. In the monoculture-based production system, chrysanthemum is generally affected by the Fusarium wilt, caused by Fusarium oxysporum f. Chrysanthemi (F. oxysporum), which is considered to be the most important soil-borne facultative pathogen, causing economically important losses of chrysanthemum and limiting chrysanthemum production [3]. Soil microbial properties and enzyme activities are closely related because transformations of the important organic elements occur through microorganisms [9,10]. The repeated application of fungicides inevitably suppresses the population of beneficial soil microbes and encourages the development of genetic resistance in the pathogen. Efforts are being made to elaborate biological control methods, one of which involves bio-organic fertilizers (BOFs) [11,12,13,14]

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