Whitefly control for tomatoes and peppers

Whiteflies (molice) are tiny insects that rest on the underside of leaves, lay eggs there and cause yellowing, sticky honeydew and black sooty mould on vegetables such as tomatoes, peppers, lettuce, cabbage and broccoli. Two common species are the greenhouse whitefly (Trialeurodes vaporariorum) and the cabbage whitefly (Aleyrodes proletella), which differ in wing markings and preferred host plants. Effective control starts with careful inspection of leaf undersides, using a magnifying lens to locate adults, eggs and nymphs, and selecting treatments that match the specific species and crop.

A low‑cost, non‑chemical method is to create a yellow sticky trap from a painted plastic bottle or sheet. Yellow reflects wavelengths that attract whiteflies, drawing them to the surface where they become stuck. The trap can be made by spraying a bottle yellow, cutting it into rectangles, attaching a string and hanging it at canopy height. Sticky boards, yellow plastic plates coated with a thin layer of petroleum jelly, or commercially available adhesive sheets work similarly. Bacillus thuringiensis products target caterpillars but do not affect whiteflies, so they should not be used for this pest.

These DIY traps can be assembled in about ten minutes with inexpensive materials and placed before planting or early in the season to reduce whitefly populations and protect vulnerable crops.