Evaluation of a fog cooling system for applying plant-protection products in a greenhouse tomato crop

Abstract

The hand-held high-volume spray techniques used to apply plant-protection products in glasshouses in south-eastern Spain have poor efficiency due to heavy losses to the soil and to high risks of worker exposure. Therefore, it is necessary to develop alternative techniques to reduce these problems. The main objective of fog cooling systems is to control the climate inside the greenhouse, but the possibility of adding the extra function of plant protection without the presence of an operator inside the greenhouse, thereby accelerating the payback on the investment in equipment, has stirred interest among farmers. In the present study, the capabilities of fog cooling system were investigated in comparison with conventional spray guns. The results show that the deposition values on the crop were very low, far below the values reached with spray guns. Also, losses increased, due mainly to evaporation of droplets, despite saturating the atmosphere of the greenhouse before applications. The need to saturate the atmosphere implying an expense in water that is not necessary with spray guns.