Hostname: page-component-78c5997874-t5tsf Total loading time: 0 Render date: 2024-11-18T04:23:00.870Z Has data issue: false hasContentIssue false

Population dynamics of epiphytic mycoparasites of the genera Clonostachys and Fusarium for the biocontrol of black pod (Phytophthora palmivora) and moniliasis (Moniliophthora roreri) on cocoa (Theobroma cacao)

Published online by Cambridge University Press:  24 June 2003

G. Martijn ten HOOPEN
Affiliation:
CABI-CATIE-DGIS, c/o Centro Agronómico Tropical de Investigación y Enseñanza (CATIE), 7170 Turrialba, Costa Rica.
Robert REES
Affiliation:
CABI-CATIE-USDA, c/o Centro Agronómico Tropical de Investigación y Enseñanza (CATIE), 7170 Turrialba, Costa Rica. E-mail: ukrauss@catie.ac.cr Institute for Cell and Molecular Biology (ICMB), Rutherford Building, Mayfield Road, Edinburgh EH9 3JH, UK.
Philo AISA
Affiliation:
CABI-CATIE-USDA, c/o Centro Agronómico Tropical de Investigación y Enseñanza (CATIE), 7170 Turrialba, Costa Rica. E-mail: ukrauss@catie.ac.cr Cocoa and Coconut Research Institute of Papua New Guinea, Tavilo Centre, P.O. Box 1846, Rabaul, East New Britain Province, Papua New Guinea.
Tim STIRRUP
Affiliation:
CABI-CATIE-USDA, c/o Centro Agronómico Tropical de Investigación y Enseñanza (CATIE), 7170 Turrialba, Costa Rica. E-mail: ukrauss@catie.ac.cr Department of Natural Sciences, Bath University, Bath BA2 7AY, UK.
Ulrike KRAUSS
Affiliation:
CABI-CATIE-USDA, c/o Centro Agronómico Tropical de Investigación y Enseñanza (CATIE), 7170 Turrialba, Costa Rica. E-mail: ukrauss@catie.ac.cr
Get access

Abstract

Mycoparasites collected from aerial parts of the cocoa plant (Theobroma cacao) have shown great promise in the control of black pod, caused by Phytophthora palmivora, and moniliasis, caused by Moniliophthora roreri. However, the ecology of epiphytic mycoparasites is still poorly understood although it has a direct bearing on applied biocontrol practices, ranging from the identification and isolation of promising biocontrol candidates to formulation needs and required application frequency. One objective of this study was to determine the natural abundance of mycoparasites on cocoa flowers and pods in relation to crop development stage and cultivar. For this purpose, native mycoparasites were detected on cocoa flowers and pods using the precolonised plate baiting technique. Furthermore, the survival of an applied Clonostachys rosea isolate on cocoa pods on shaded and non-shaded trees was compared as well as the recolonisation patterns of surface-sterilised pods by native mycoparasites under these conditions. Clonostachys spp. were the most commonly isolated native mycoparasites, followed by Fusarium spp. No differences in the occurrence of native, epiphytic mycoparasites were observed between the three main cocoa cultivars, ‘Criollo’, ‘Forastero’ and ‘Trinitario’, nor between clones within these groups. Thus, a single biocontrol inoculum can be suitable for application to cultivar mixtures of cocoa commonly grown together in a field. Different susceptibility classes of segregating F1 populations of hybrids with resistance against M. roreri and P. palmivora supported similar population levels and taxonomic assemblages of mycoparasites. Therefore, we reject the hypothesis that these antagonists mediate resistance. Mycoparasite abundance and genetic disease resistance to black pod and moniliasis are independent phenomena and should lead to additive effects if employed simultaneously in an integrated disease management programme. The survival of applied C. rosea was not affected by the shading regime or any other meteorological parameter measured. On the other hand, recolonisation of surface-sterilised cocoa pods by most native mycoparasites was faster in the shade. Only Trichoderma spp. colonised pods exposed to direct sunlight faster than shaded ones. The implications for the design of biocontrol inocula and formulation technology are discussed.

Type
Research Article
Copyright
© The British Mycological Society 2003

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)