Articles
Exploring novel soil organic amendments to implement suppressive soils against Fusarium oxysporum f. sp. lactucae
Article number
1410_13
Pages
89 – 96
Language
English
Abstract
Plant diseases caused by soil-borne pathogens have become a major problem since the implementation of restrictions on the use of chemical fumigants.
This demands novel sustainable alternatives to control soil-borne pathogens such as Fusarium oxysporum f. sp. lactucae (FOL). The objective was to assess the potential of microbial communities from different soil chitinous amendments to develop suppressive soils as an alternative to chemical fumigation.
Four different amendments, three of them chitin-rich, were tested: frass from black soldier fly larvae (BSFL, Hermetia illucens); commercial chitin; commercial compost, and commercial chitin + compost.
To stablish the microbial communities in the soil, a batch of amended soils was incubated for four months before the experiment.
Another batch used soils freshly amended.
Before the lettuce experiment setup, soils were inoculated with FOL race 1. A non-amended soil was used as control.
Lettuce plants were grown in the resulting soil.
Foliar severity and final aerial fresh biomass were measured.
The experimental design included five treatments, three blocks and three randomized replicates per block and treatment (9 plants per treatment). In samples incubated for four months, foliar severity of FOL was significantly reduced (P<0.05), and fresh lettuce biomass was significantly increased in the soils amended with commercial chitin.
In samples amended with BSFL frass, these same differences were only significant when compared to the non-amended soil (P<0.05). A positive correlation was observed between the fresh lettuce biomass and the relative abundance of micrococcales (r=0.77, P<0.01) and propionibacteriales (r=0.69, P<0.01). These changes in the microbial community structure may indicate that these amendments may be promoting the development of soil microbial communities responsible for natural soil suppressiveness of FOL. The soil microbial community structure of each treatment needs further analyses to identify potential microorganisms responsible for FOL suppressiveness.
This demands novel sustainable alternatives to control soil-borne pathogens such as Fusarium oxysporum f. sp. lactucae (FOL). The objective was to assess the potential of microbial communities from different soil chitinous amendments to develop suppressive soils as an alternative to chemical fumigation.
Four different amendments, three of them chitin-rich, were tested: frass from black soldier fly larvae (BSFL, Hermetia illucens); commercial chitin; commercial compost, and commercial chitin + compost.
To stablish the microbial communities in the soil, a batch of amended soils was incubated for four months before the experiment.
Another batch used soils freshly amended.
Before the lettuce experiment setup, soils were inoculated with FOL race 1. A non-amended soil was used as control.
Lettuce plants were grown in the resulting soil.
Foliar severity and final aerial fresh biomass were measured.
The experimental design included five treatments, three blocks and three randomized replicates per block and treatment (9 plants per treatment). In samples incubated for four months, foliar severity of FOL was significantly reduced (P<0.05), and fresh lettuce biomass was significantly increased in the soils amended with commercial chitin.
In samples amended with BSFL frass, these same differences were only significant when compared to the non-amended soil (P<0.05). A positive correlation was observed between the fresh lettuce biomass and the relative abundance of micrococcales (r=0.77, P<0.01) and propionibacteriales (r=0.69, P<0.01). These changes in the microbial community structure may indicate that these amendments may be promoting the development of soil microbial communities responsible for natural soil suppressiveness of FOL. The soil microbial community structure of each treatment needs further analyses to identify potential microorganisms responsible for FOL suppressiveness.
Authors
P. Hernández-Muñiz, C. Borrero, M. Avilés, J.D. Fernández Bayo
Keywords
sustainable pest management, soil-borne pathogens, chitin, black soldier fly
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