Abstract: Bemisia tabaci is a major pest of tomato crops. Barrier-trap plants involve the use of plant species that interfere with the dynamics of pests in the main crop. The objective of this work was to determine the function of Lagenaria siceraria as a barrier-trap for B. tabaci in tomato greenhouses. The presence of pumpkin in the front of greenhouses reduced significantly the abundance of the whitefly on tomato crops. This viable and environmentally friendly practice may contribute to the control of whiteflies in tomato greenhouses.