Abstract

SILVA, Anderson Miguel da et al. Impact of different levels of artificial defoliation in cotton phenology. Rev. de Ciências Agrárias [online]. 2012, vol.35, n.1, pp.163-172. ISSN 0871-018X.

Pests and diseases of foliage, phytotoxicity of chemicals, hail and some mechanical injuries are the main agents of defoliation in cotton. The purpose of this research was to study the effect of defoliation levels at different growth stages of cotton. The study was conducted in a greenhouseand the experimental design was completely randomized in factorial 5 x 5 and growth stage. The response-variables were: bolls produced (TC), bolls viable (CV) and boll weight (PC). In conclusion there was loss in productivity for all levels of defoliation in all growth stages of cotton, except defoliation until 25% in V3 and F5 stages. Defoliation performed in early fruiting stage (F5) resulted in significant losses in cotton yield after 50 % leaf area reduction.

Keywords : Defoliating pest; economic injury level; economic threshold; Gossypiumhirsutum; leaf area.

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