To quantify the presence of whitefly (Bemisia tabaci Genny), thrips (Frakliniella occidentalis Pergande), and leaf miners (Liriomiza trifolli Burgess) in the exterior and interior of greenhouses, and the effect of screens as physical barriers on the yield and quality of tomatoes (Solanum lycopersicum L.), five screens with different porosities were installed on the side windows of greenhouses. The amount of the three insects outside the greenhouses was 30% greater than in the interior. Mesh with 39% porosity limited to 30 and 18% the abundance of B. tabaci and F. occidentalis, while L. trifolli decreased 30% using 37.5% or 37.9% porosity meshes. Greater tomato yield was obtained with 39% porosity mesh on the greenhouse side windows.