Tropentag, September 10 - 12, 2025, Bonn "Reconciling land system changes with planetary health"

Cotton growth compensation affected by Fusarium oxysporum and root-knot nematodes in Benin

¹University of Abomey-Calavi, Benin
²University of Parakou, Fac. of Agronomy, Benin

Abstract

Fusarium oxysporum is a soil-borne phytopathogen responsible for substantial yield loss in cotton cultivation. Its pathogenic impact is exacerbated by interactions with root-knot nematodes (Meloidogyne spp.) intensifying disease impact on plants. This study aimed at assessing different F. oxysporum densities and root-knot nematodes (Meloidogyne incognita) effects on three cotton varieties (OKP 768, ANG 956 and KET 782) growth and development under greenhouse conditions. A completely randomised design was used, with twelve combined treatments of Fusarium densities and nematodes, each repeated six times. A combination of five inoculum densities of F. oxysporum conidia (D1: 2.106; D2: 4.106; D3: 6.106; D4: 8.106 and D5: 1.107/pot); one inoculum density of nematodes (1,500 juveniles/pot) and a control with neither nematodes nor Fusarium were used as treatments. After cotton sowing, nematodes and F. oxysporum conidia were inoculated (one and two months, respectively) in a crown around the plants’ collars. During the trial, the temperature inside the greenhouse varied between 27.07°C and 36.80°C, while humidity varied between 37.75% and 83.00% reflecting optimum conditions. Treatments combining nematodes with Fusarium densities at 8.106 and 1.107 negatively affect cotton growth and development, validating an existing interaction between M. incognita and F. oxysporum. With these treatments, ANG 956 and KET 782 plants failed to produce floral buds and fruit branches. Nevertheless, despite being severely affected, the variety OKP 768 performed well, having the greater growth values with floral buds and fruit branches production. Fusarium applied at 8.106 and 1.107 with nematodes induced higher area under disease progression curve and xylem discolouration than other treatments, inducing plant growth to decrease for ANG 956 and KET 782 in contrary to OKP 768. The variety OKP 768 can constitute an asset for tolerant/resistant cotton varieties development.

Keywords: Benin, conidial density, disease, Gossypium spp., Meloidogyne incognita, varietal resistance

Contact Address: Tinon Nehal Djaouga Mamadou, University of Abomey-Calavi, BP 21, Parakou, Benin, e-mail: tinondjaougagmail.com