Silica coated insect proof screens for effective insect control in greenhouses

Abstract

Insect proof screens were coated with silica (SiO₂) nanoparticles using the plasma coating process. The work studied whether a screen coated by SiO₂ nanoparticles could be more effective on insects' control than a non-coated screen. Thus, the insect control properties of 25- and 40-mesh screens were studied. Besides, a series of experiments were performed to investigate the mechanical, optical, and airflow properties of different (25, 40, and 50) mesh screens coated or not with SiO₂ nanoparticles. The air permeability of the screens was affected, while the mechanical and optical properties of the screens were not significantly affected by the SiO₂ coating. Compared to 40- and 50-mesh non-coated screens, a 25-mesh SiO₂-coated screen had 54% and 66% higher air permeability values, respectively. The mean number of aphids infesting the leaves and stems of the crop grown under a 25- or a 40-mesh SiO₂-coated screen was up to 93% and 81% lower than those grown under the non-coated screens, respectively. The number of aphids found on plants grown under a 25-mesh SiO₂-coated screen were significantly lower (about 80%) than those recorded under a 40-mesh non-coated screen. Based on the differences observed on screen's air permeability and on greenhouse ventilation models available in the literature, it was estimated that a greenhouse with a 25-mesh SiO₂-coated screen will have 11.5% and 23.1% higher ventilation rate than a greenhouse with a 40- or 50-mesh non-coated screen, respectively.