Towards integrated pest management of cocoa black pod disease in Sierra Leone: host genetic diversity, agroforestry systems, and biological control

Sammanfattning

Cacao (Theobroma cacao L.) is a key agricultural commodity in West Africa, which produces approximately 70 % of global cocoa. In Sierra Leone, cocoa provides vital income for smallholder farmers, but productivity is constrained by with diseases such as cocoa black pod disease (CBPD) caused by Phytophthora species. Accurate genetic identification is essential for effective resistance breeding programs, conservation efforts, and distribution of true-to-type planting materials to farmers. This thesis takes an integrated approach to management of CBPD combining an investigation into the genetic diversity of T. cacao, a survey of the agroforestry approaches used by farmers and testing of biological control solutions for sustainable CBPD control in Sierra Leone. Genetic characterization of cacao germplasm reveals substantial variability within populations, with most variation occurring within rather than between accessions. CBPD prevalence across Sierra Leone's cacaogrowing regions is strongly influenced by agroforestry system design. Dense shade and high canopy cover increase disease incidence through elevated humidity and reduced airflow, while greater tree-species diversity modestly reduces disease occurrence. Field applications of the biological control agent Trichoderma atroviride reduce CBDP incidence and increase yield, offering a promising sustainable alternative to the use of synthetic pesticides. The holistic approach taken in this thesis addresses key production constraints while promoting resilience and environmental sustainability in smallholder cacao systems.

Nyckelord

Cocoa Black Pod Disease; Phytophthora megakarya; Phytophthora palmivora; Cacao Agroforestry Systems; Trichoderma atroviridae; Theobroma cacao; smallholder farming; biocontrol; West Africa; IPM

Publicerad i

Acta Universitatis Agriculturae Sueciae
2026, nummer: 2026:36
Utgivare: Swedish University of Agricultural Sciences

SLU författare

• Luseni, Mohamed Mambu

  • Institutionen för växtskyddsbiologi, Sveriges lantbruksuniversitet
    

UKÄ forskningsämne

Jordbruksvetenskap
Genetik och förädling inom lantbruksvetenskap

Publikationens identifierare

• DOI: https://doi.org/10.54612/a.40u5s5qqng
• ISBN: 978-91-8124-253-9
• eISBN: 978-91-8124-283-6

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/146723