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

Abstract

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.

Evaluating the potential of soil management to reduce the effect of Fusarium oxysporum f. sp. cubense in banana (Musa AAA)

“…This effect of those soil properties could have played a role in the devastation of Gros Michel by Foc Race 1 in Latin America during the last century. The decimation of the former main banana subgroup (the Gros Michel) appears expectable with the incipient knowledge about the fungus and its dissemination (Dita et al 2018) and the recently reported interactions of Foc with e.g., soil nematodes (Rocha et al 2020) and the banana weevil (Guillén et al 2021). Due the lack of awareness about the importance of tested soil properties in the expression of the disease, the standard management of the crop with the common application of high rates of N (and the consequent drop of pH) could increase the severity of the disease.…”

Quantifying the Role of Ground Beetles for the Dispersal of Fusarium and Alternaria Fungi in Agricultural Landscapes

“…Therefore, fungal propagules can be found in the digestive system or the feces of these animals of different trophic levels [5,13]. Furthermore, the propagules can adhere to the exoskeleton (ectozoochory) of the arthropods while they move between infected plant material [14,15]. Moyo et al [5] found on herbivory and on predatory arthropods phytopathogenic fungi and showed that herbivore species transmitted the pathogen to healthy plants and that their feces are a source for inoculation.…”

Incidence, Spatial Pattern and Temporal Progress of Fusarium Wilt of Bananas

“…It is hypothesized that feral pigs surrounding the fields [ 53 ] and humans [ 54 ] are involved in the within and among field dispersal of Foc [ 7 , 21 ]. Insects as weevil borers can carry infective propagules of Foc [ 55 ] and their populations were driving FWB epidemics in banana fields [ 19 ].…”