SUMMARY In Uruguay pest and disease control is the main problem in greenhouse horticultural crops. The aims of this study were to characterize the use of current plant treatment techniques and to evaluate alternatives to optimize plant treatment in greenhouses. Manual vertical boom, hydraulic spraying, air assisted spraying with and without electrostatic charge and cold foggers in pepper and tomato crops were evaluated. We conducted surveys among farms, which revealed that the carrier volume at full development of tomato crops was approximately 1300 l.ha-1. Significant differences in application rate were detected between farms with similar conditions. The use of vertical booms, with very fine droplets of 100 ?m, produced declining coverage in abaxial and adaxial surfaces. Droplets of 220 ?m and application rate of 520 l.ha-1 gave similar results in leaf coverage compared to 345 ?m and 1100 l.ha-1. When the nozzles were oriented 45 degrees upwards, similar coverage was achieved on the top side of the leaves, but coverage of the bottom side of the leaves was increased when compared with horizontal nozzles. In tomato crop, pneumatic application with the low volume sprayer ESS (GPS5K MODEL, Electrostatic Spraying Systems, Inc., Watkinsville, Ga), with and without electrostatic charge with application rates of 170 l.ha-1, produced greater uniformity of coverage between outer and inner foliage than conventional hydraulic high volume spraying with application rates of 1000 l.ha-1. In pepper, the use of electrostatic charge increased coverage on the top and bottom side, both at 56 and 103 l.ha-1 compared with the non-charged treatment. Similar coverage was obtained using a knapsack pneumatic sprayer, but the application rate was 240 l.ha-1. In tomato, five methods of manual application were evaluated for their effectiveness against whitefly (Trialeurodes vaporariorum W), moth (Tuta absoluta Meyr) and botrytis (Botrytis cinerea Pers): high volume hydraulic spraying (800 l.ha-1), reduced volume hydraulic spraying (350 l.ha-1), pneumatic knapsack (175 l.ha-1) and pneumatic spraying with and without electrostatic charge (100 l.ha-1). The pneumatic spray treatments were more effective than hydraulic spraying. Applications with the ESS sprayer with and without electrostatic charge and average application rate of 100 l.ha-1 were the most effective on all occasions. Product distribution by a cold fogger in greenhouse pepper, was highly variable, with a high decrease in deposits while increasing the fogger?s distance. Despite the observed spatial heterogeneity, droplet density was similar between the most exposed surfaces at the top of the crop and the least exposed inside the canopy pepper, with an average impact density of 1800 cm-2. The impacts on the foliage were almost exclusively seen on the top side of leaves. Deposits on the bottom side were observed only on twisted or inverted leaves. With the cold fogger, the thrips control (Thrips sp.) was high inside the whole greenhouse throughout the crop cycle. Controlling pepper powdery mildew (Leveillula taurica (LŠv) G. Arnaud) was generally acceptable but with significant spatial variations. During the five-month experiment there was no need for manual applications of pesticides inside the greenhouse.