Manual topping decreases bollworm infestations in cotton cultivation in Mali

Renou Alain, Téréta Idrissa, Togola Mamoutou. 2011. Manual topping decreases bollworm infestations in cotton cultivation in Mali. Crop Protection, 30 (10) : 1370-1375.

Quartile : Q2, Sujet : AGRONOMY

Résumé : In sub-Saharan areas of Africa, cotton growers no longer cut the shoot tips from plants (topping), although manual topping was promoted at the start of the 20th century to improve yield and, surprisingly, to reduce pest incidence. In these areas, the bollworms Helicoverpa armigera Hübner, Earias spp., and Diparopsis watersi Rothschild are responsible for the majority of cotton yield losses, and the use of pyrethroids has resulted in resistance in field populations of H. armigera. In the face of these problems and given the scarcity of literature on the effects of topping on pest control, we assessed bollworm infestation levels in 12 trials comparing manual topping and non-topping cotton plots in Mali over a sixyear period (2002, 2003, and 2005 to 2008). Topping was performed at the emergence of the 15th sympodial branch or at 10 days after the first flower opening. Our results showed no significant difference in seed cotton yields between topped and non-topped cotton. Bollworm infestations (all species) were always lower on topped cotton and 7 out of 12 trials showed significantly lower infestations on topped cotton. In plots of topped cotton, we recorded an average of 56% fewer H. armigera larvae, 68% fewer Earias spp. larvae, and 71% fewer D. watersi larvae with respectively 5, 4, and 3 out of 12 trials with significant differences in favor of topping and no significant difference in favor of non-topping. To our knowledge, our study is the first to report decreases in D. watersi larval infestation with cotton topping. Further studies are required to understand the mechanisms involved in these effects and to ensure that topping is economically attractive for farmers.

Mots-clés Agrovoc : Gossypium hirsutum, Helicoverpa armigera, Diparopsis

Mots-clés géographiques Agrovoc : Mali

Mots-clés complémentaires : Diparopsis watersi

Classification Agris : H10 - Ravageurs des plantes

Champ stratégique Cirad : Axe 1 (2005-2013) - Intensification écologique

Auteurs et affiliations

• Renou Alain, CIRAD-PERSYST-UPR SCA (MLI)
• Téréta Idrissa, IER (MLI)
• Togola Mamoutou, IER (MLI)

Source : Cirad - Agritrop (https://agritrop.cirad.fr/561537/)

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