Insect traps are disclosed that comprise a substrate (10, 20) upon which is carried an active coating (14, 24) destructive to insects. The substrate (10, 20) has markings that form a visually-distinctive, contrasting visual pattern (16, 26) in the region of the active coating (14, 24). The traps have particular, but not exclusive, application to trapping greenhouse pests, such as whitefly and thrips. A range of alternative marking patterns (16, 26) and colour combinations are disclosed. The destructive coating may include an adhesive and a chemical insecticide. Additionally, the coating may include one or more semiochemical, such as a pheromone or an allomone.
