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This study was carried out with IAC-19 cotton variety during 1983/84 aiming; a) to assess the performance of the electrodynamic sprayer (Electrodyn) in the control of P. latus and Tetranychus (T.) urticae on cotton plants and compare with conventional sprayer; b) to determine, for different Electrodyn nozzles, some spray parameters such as the type and rate of plant coverage, droplet density and VMD/NMD ratio. The performance of Electrodyn sprayer, in different spray procedures over 6 growth stages of cotton plants, was studied using fluorescent dye technique. Droplets were sampled on MgO coated microscope slides and measured by Fleming particle analyzer. Dicofol at 40%, 0,14% and 0,11% respectively for Electrodyn sprayer tractor mounted conventional sprayer and hand operated knapsack sprayer was used in the study of mite control. The results allowed the following conclusions: a) The Electrodyn sprayer performed fairly well in the droplet coverage trial. Coverage indexes of under surface of leaves was always lower than the indexes for upper surface coverage in all the situations and growth stages studied. Nevertheless these index were considerable, mainly at the initial growth stages of the crop; b) Electrodyn nozzles with smaller output provided better coverage index of both leaf surfaces and in all leaf positions under different spray procedures, almost in all growth stages studied; c) For plants up to 35 cm in height (11.27 dm² of leaf surface) the spray with Electrodyn should be carried out at 10 cm to 20 cm over the plant; for plants higher than 55 cm (26.04 dm² of leaf surface) the nozzle should be carried at the plant height between rows because nozzle positioning over plant is not effective since this growth stage; d) Electrodyn sprayer produced droplets with high uniformity with VMD/NMD ratio ranging from 1.10 to 1.21 (attending to specification for CDA); for Uvitex fluorescent dye solution the VMD of droplets from different nozzles ranged from 59 to 98 micrometres and for dicofol ED 40 formulation, from 56 to 94 micrometres; e) For the same flow rate the droplet size from Uvitex solution is similar to dicofol ED 40 formulation; for both liquids, nozzle with higher flow rate produces bigger droplets at the same electric charge level; f) All treatments tested at field conditions showed the same efficacy in the control of P. latus and Tetranychus (T.) urticae on cotton plants. Considering the standard procedures for tractor mounted or knapsack sprayers, the use of Electrodyn points out the possibility for a drastic reduction of the spray volume, maintaining the same efficacy in the of mites.