Skip to main content
ARS Home » Research » Publications at this Location » Publication #92001
Title: BIOLOGICAL CONTROL OF BLACK POD AND WITCHES'-BROOM DISEASE IN CACAO

Author
item HEBBAR, PRAKASH - PENN STATE UNIVERSITY
item GUILTINAN, MARK - PENN STATE UNIVERSITY
item Lumsden, Robert

Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: 6/13/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary: N/A

Technical Abstract: At least five major cacao diseases destroy annually 40% of the total crop. A large percentage of these losses are due to fungal diseases caused by Phytophthora spp. (black pod) and Crinipellis perniciosa (witches'-broom). The current control strategies available are labour intensive or are at an early stage of development. Research on biological control has been limited to antagonistic fungi such as Cladobotryum amazonense and Trichoderma spp., which were shown to have some potential to control witches'-broom. The constraints that exist for the large scale application of bioagents are lack of knowledge on the ecology of cacao-associated microorganisms and lack of selection and application strategies of microbial strains. The objective of this research was to study the microbial populations associated with the various parts of cacao thought to be the "sites of infection" for the pathogens and to identify those associated with cacao with a potential for biological control. The study indicated that bacteria, fungi and actinomycetes were found associated with both aerial parts and the rhizosphere of cacao. However, yeasts were detected only on the aerial parts of the plant. Bacteria associated with the aerial parts were highly pigmented. Total populations of bacteria, fungi and actinomycetes from the susceptible and tolerant cultivars were not different from each other, total populations of yeasts were higher in the tolerant than in the susceptible cultivar. Biocontrol agents such as pseudomonads, Burkholderia cepacia and Trichoderma spp. were detected mainly in the soil and on the roots. Greenhouse tests are in progress.