Methodology of the application of pyrethroids against cotton boll weevil and pink bollworm

Abstract

Abstract Field experiment was conducted at Queimadas, Paraiba, Brazil, during the cotton season of 1987 to evaluate methodologies of the application of Cyfluthrin EC and Cypermethrin ED against cotton boll weevil (Anthonomus grandis) and pink bollworm (Pectinophora gossypiella). The results obtained showed that: (1) Cytfluthrin EC, at 15 g, 20 g and 40 g a.i./ha, applied with handoperated knapsack sprayer along every row and alternate cotton rows, and Cypermethrin ED, at 3–91 g and 7–81 g a.i./ha, applied with ElectroDyn sprayer nozzle taken along alternate and interrow space, respectively, are effective for the control of the cotton boll weevil and pink bollworm. (2) Optimum methodologies of application of Cyfluthrin EC and Cypermethrin ED to control cotton boll weevil and pink bollworm are spraying the insecticides in alternate rows and inter‐row spaces, respectively. (3) The percentage of damage loculi of boll by cotton boll weevil is not suitablé for evaluating insecticides against cotton boll weevil. (4) The decreased dosages and specific placement of the Cyfluthrin EC and Cypermethrin ED in relation to pest behaviour are important tools in programmes of cotton boll weevil and pink bollworm management.