CLADOBOTRYUM MYCOPHILUM, CAUSAL AGENT OF COBWEB DISEASE ON COMMERCIAL AGARICUS BISPORUS AND PLEUROTUS ERYNGII CROPS IN SPAIN

ABSTRACT Between 2008 and 2011, outbreaks of cobweb were observed in commercial white button and king oyster mushroom crops in Castilla-La Mancha (Spain) based on morphological and genetic analysis the casual agent was identified as Cladobotryum mycophilum. Two Agaricus bisporus mushroom cropping trials inoculated with C. mycophilum were performed. The total area of the crop affected by cobweb was 30% in the inoculated blocks of trial A and 45% in trial B. The non-inoculated blocks remained healthy. Compared with the uninoculated controls, a decrease in the yield of 10.7% was observed in trial A and 9.1% in trial B. Pathogenicity trial was also performed using blocks containing sterilized, spawned and incubated P. eryngii substrate. The first cobweb symptoms developed 23 days after inoculation and C. mycophilum was consistently re-isolated from nine (37.5%) of the inoculated blocks. Non-inoculated blocks remained healthy. In a second test, conidial suspensions of three isolates of C. mycophilum were inoculated onto P. eryngii fruit bodies. C. mycophilum grew between 80 and 85% of the inoculated fruit bodies, while the control fruit bodies remained symptomless

Genetic Analysis and In Vitro Enzymatic Determination of Bacterial Community in Compost Teas from Different Sources

16 páginas.-- 2 figuras.-- 5 tablas.-- 53 referenciasCompost tea has been used throughout the world to control diseases and promote the growth of plants. The microbial community is the main factor involved both in the antagonistic effect against relevant phytopathogens and as a stimulator of plant growth. The objective of this research is to determine the bacterial diversity present in four types of compost as well as some of the mechanisms that may be involved in the positive effects of compost tea on crops. Aerated (ACT) and non-aerated (NCT) compost teas were obtained from four different composts: spent mushroom substrate compost (SMC), grape marc compost (GMC), greenhouse horticultural crop residues compost (CRC), and vermicompost (CRV). 16S rDNA-based DGGE profiles were obtained for each compost tea and their respective bacterial communities were analyzed. Of the 100 clones obtained, those typical for being dominant for all profiles were chosen. In total, 20 different clones were sequenced. The results showed that the bacterial communities of most compost teas had high richness, diversity, and evenness values, with relative abundance of species belonging to Bacteroidetes and Proteobacteria. The NCTs obtained from all the composts, especially CRC and CRV, showed high levels of siderophore production, while teas from GMC manifested high and consistent cellulase activity. The ACTs from all the composts, especially SMC, had high protease activityThe present work benefited from the input of the project RTA2010-00011-C02-02. “Caracterización microbiológica y optimización de los mecanismos de supresividad de sustratos postcultivos de hongos comestibles frente a enfermedades del champiñón, ” from Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA) supported by the Spanish Ministry of Science and Innovation.Peer reviewe