Relation Between Suppressiveness to Tomato Fusarium Wilt and Microbial Populations in Different Growth Media

Abstract

Tomato Fusarium wilt suppressiveness of three growth media, with respect to peat and vermiculite, and the relationship between microbial populations of growth media in the severity of this pathogen were examined. The growth media evaluated were olive oil husk + cotton gin trash composted and mixed with rice husk (OC+R), spent mushroom composted and mixed with peat (SM+P) and coir fibre. To determine the role of the microflora in the suppression, the two composts were also heated to 60ºC for 6 days. Three bioassays were carried out with these infested growth media and controls not infested. Disease severity was recorded during 25 days after tomato seedling transplantation. In these seven growth media the density of culturable groups of microorganisms was determined by dilution plating on semi-selective media before the bioassays. The two composts showed suppressiveness to Fusarium wilt with respect to vermiculite and peat while coir fibre was conductive. Furthermore, in OC+R its suppressiveness is due more to the growth media's non heat-labile properties than in SM+P. Significant negative correlations were found between severity and Bacillus spp., cellulolytic actinomycetes and bacteria, oligotrophic actinomycetes and bacteria, copiotrophic bacteria, total actinomicetes (cellulolytic + oligotrophic + copiotrophic) and total bacteria (cellulolytic + oligotrophic + copiotrophic) populations in these growth media. Bacillus spp. are known antagonists, so they may account for the suppressiveness in our composts. Cellulolytic and oligotrophic actinomycete populations were associated with Fusarium wilt suppressiveness for another growth media. High microbial activity has been reported as a Fusarium wilt suppressiveness factor. Copiotrophic, celullolitic and oligotrophic bacteria contribute to this microbial activity.

Carnation Fusarium wilt suppression in four composts

“…For both Fusarium wilts, GMC was the most suppressive. The carnation Fusarium wilt suppressiveness registered for OC + R and SM + P was also established for tomato Fusarium wilt (Borrero et al 2005). Our results are consistent with those of other studies, where peat was found to be conducive for several Fusarium wilts, while successful disease suppression was provided by composts (Noble and Coventry 2005).…”

“…These formae speciales are Fusarium wilt of carnation (Cebolla and Pera 1983;Orlikowski 1983;Pera and Calvet 1989), chrysanthemum (Chef et al 1983), cyclamen (Garibaldi 1988), flax (Chef et al 1983), iris (Garibaldi 1988), radish (Trillas-Gay et al 1986), sweet basil (Reuveni et al 2002) and tomato (Szczech 1999;Cotxarrera et al 2002). We have also previously evaluated the suppressiveness to tomato Fusarium wilt of four composts in comparison to peat and vermiculite Borrero et al 2004Borrero et al , 2005. The pH and microbial activity of the composts were used to predict their suppressiveness to tomato Fusarium wilt (Borrero et al 2004).…”

Effect of <i>Bacillus velezensis</i> and <i>Glomus intraradices</i> on Fruit Quality and Growth Parameters in Strawberry Soilless Growing System

“…Regarding the physicochemical properties of the growth medium, coconut fiber growth medium showed electrical conductivity of 1. Tuitert et al (1998) with modifications as in Borrero et al (2005). The Bacillus spp.…”

Fusarium oxysporum f. sp. lycopersici and compost affect tomato root morphology

“…(Kavroulakis et al 2010), fluorescent Pseudomonas spp. (Duijff et al 1998;Mazurier et al 2009), Actinomycetes (Borrero et al 2005) and Trichoderma spp. (Cotxarrera et al 2002) with both competition and induced systemic resistance as mechanisms described.…”