Can the banana weevil Cosmopolites sordidus be a vector of Fusarium oxysporum f.sp. cubense race 1? Unravelling the internal and external acquisition of effective inoculum

• Published in: Pest management science Vol. 77; no. 6; pp. 3002 - 3012
• Main Authors: Guillen Sánchez, César, Tixier, Philippe, Tapia Fernández, Ana, Conejo Barboza, Ana Maria, Sandoval Fernández, Jorge A, de Lapeyre de Bellaire, Luc
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01-06-2021; Wiley Subscription Services, Inc
• Subjects: acquisition dynamics; Animals; Bananas; Controlled conditions; Digestive system; Dispersal; Foc; Fruits; Fusarium; Fusarium oxysporum; Gastrointestinal tract; Gros Michel cultivar; Inoculum; insect mediated dispersion; Insects; Musa; pathogenicity; Pest outbreaks; Plant Diseases; Propagules; Weevils; Wilt; pathogenicity; Foc; Gros Michel cultivar; acquisition dynamics; insect mediated dispersion
• ISSN: 1526-498X; 1526-4998
• DOI: 10.1002/ps.6339

BACKGROUND
With the undergoing world outbreak of Fusarium wilt of bananas, it is essential to unravel all the possible process of dissemination of this disease. The host‐pest interactions of the banana weevil with banana plants make this insect an important potential vector. This study, carried out in controlled conditions, explores the interaction between the banana weevil and Fusarium oxysporum f.sp. cubense race 1 (Foc), with a focus on the external and internal transport of viable fungal propagules.
RESULTS
Viable inoculum of Foc was detected very rapidly on external teguments and in the digestive tract of the insect, i.e. at the lowest time studied of 5 min after contact with infected pseudostems. Maximal inoculum acquisition occurred after 1 h contact with an inoculum source. External inoculum was higher than the inoculum present in the digestive tract, but external and internal inoculum had the same dynamics. After a contact of an infected source, external and internal inoculum decreased exponentially within 50 h, but weevils remained infested for a long time, as long as 2 or 3 days that would be enough for inoculum dispersal. Viable inoculum was also detected in feces. Foc strains isolated were pathogenic when inoculated to banana plants of the Gros Michel variety but did not provoke any symptom on Cavendish banana plants.
CONCLUSION
These results demonstrate that the infective structures of Foc remain externally viable in the digestive system and the excreta of the banana weevil. Such excreta are capable of making healthy banana plants of the Gros Michel variety.
© 2021 Society of Chemical Industry.
Cosmopolites sordidus is able to transport viable propagules of Fusarium oxysporum fsp cubense race 1, causal agent of Fusarium wilt of bananas, on its external teguments, in its digestive tract and in its feces.