Production and Germination of Conidia of Trichoderma stromaticum, a Mycoparasite of Crinipellis perniciosa on Cacao

Abstract

Growth characteristics of the fungus Trichoderma stromaticum, a mycoparasite on the mycelium and fruiting bodies of Crinipellis perniciosa, the causal agent of witches'-broom disease of cacao, were evaluated under controlled environmental conditions. The ability of T. stromaticum to produce conidia and germinate on dry brooms was evaluated at three constant temperatures (20, 25, and 30 degrees C) and two constant relative humidities (75 and 100%). T. stromaticum produced abundant conidia on brooms at 100% relative humidity and incubation temperatures of 20 and 25 degrees C, but none at 30 degrees C. Sporulation of T. stromaticum was not observed at 75% relative humidity at any temperature. At 100% relative humidity and either at 20 or 25 degrees C, treatment of brooms with T. stromaticum suppressed C. perniciosa within 7 days. In contrast, at 30 degrees C, treatment with T. stromaticum had no effect on the pathogen in brooms maintained at either 75 or 100% relative humidity. Mycelium of C. perniciosa grew from brooms at all temperatures at 100% relative humidity. Conidial germination on broom tissue approximated 80% at temperatures from 20 to 30 degrees C. Results suggest that applying T. stromaticum under high-moisture conditions when the air temperature is below 30 degrees C may enhance the establishment of this mycoparasite in cacao plantations.

Trichoderma stromaticum and its overseas relatives

“…However, despite a lack of taxonomic resolution, the work of de Souza et al (2006Souza et al ( , 2008, Loguercio et al (2009a, b), Medeiros et al (2010) and Sanogo et al (2002) suggests that strains of AFLP Group 1 (Clade B here) are better suited for biological control than are strains of Group 2 (Clade A here). Although T. stromaticum is very easily recognized through its morphology, the differences in phenotype between the two AFLP are not diagnostic.…”

Eficiência de fungos filamentosos no controle biológico da vassoura de bruxa do cacaueiro

“…A eficiência dos isolados de Trichoderma harzianum e T. stromaticum se deve, provavelmente, aos seus mecanismos de competitividade, de antibiose e de micoparasitismo, agindo sinergicamente no hospedeiro. Segundo Sanogo et al (2002), os microorganismos antagonistas devem competir por espaço e nutrientes com o fitopatógeno. Portanto, é importante que o fungo utilizado em biocontrole apresente uma boa velocidade de colonização, o que determina a sua habilidade em se estabelecer no substrato-alvo.…”

Isolation and Identification of Indigenous Microorganisms of Cocoa Farms in Côte d’Ivoire and Assessment of Their Antagonistic Effects Vis-À-Vis Phytophthora palmivora, the Causal Agent of the Black Pod Disease

“…An analysis of the list of the collected microorganisms revealed the existence of fungi and bacteria identified by several authors as having antagonistic effect against pathogens responsible for plant diseases. This is the case of the genus Trichoderma in which several species have been tested for the control of cocoa diseases (Sanogo et al, 2002;Krauss and Soberanis, 2001;Tondje et al, 2007;Samuels, 1996). In the group of the bacteria, the antagonistic effect of the genus Bacillus was demonstrated by Shari Fuddin, 2000.…”