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Résumé :
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The efficacy of glyphosate and glufosinate applied with two sprayers, a motorised knapsack mistblower and a hydraulic sprayer, were evaluated for the control of common reed. Phragmites australis had been cut in the beginning of September 1994, 30 d before autumn application. The study sites were cleared of vegetation to within 10 cm of the surface using an hydraulic escavator equipped with a mowing bucket, in one operation it cuts and removes the weed. Herbicides were sprayed in October 1994 and April 1995 at different spray volumes and at different rates. Glyphosate rates were 0.81, 1.62, 3.24, 4.68 and 6.48 kg a.i./ha applied with a mistblower at spray volumes of 300; 800; 1100 l/ha and with a sprayer at 800; 1600 l/ha. Glufosinate rates were 0.3, 0.6, 1.2, 1.38, 1.8 and 2.4 kg a.i./ha applied with a mistblower at spray volumes of 800 l/ha and with a sprayer at 800; 1100 and 1600 l/ha. Glyphosate provided control over 2-3 yr for dense P. australis infestations in drainage channels when applied up to 1.62 kg/ha, independently of the type of sprayer, times of treatment or spray volume. Glufosinate produced rapid phytotoxicity in aerial parts; however the autumn treatment was more efficacious than the spring one. Regrowth, during 1995, was high and 1 yr after the first application the efficacy had become very low.
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