Flies can be both annoying and a health hazard, mechanically vectoring more than 100 pathogens. Their feeding technique means that foods can be contaminated with these potentially harmful diseases. Spraying chemicals has many disadvantages but, while somewhat unsightly, a paper strip coated with a very sticky adhesive and a scent attractant is a very effective fly killer. The adhesive is often a combination of rosin and rubber, both natural products and the scent a food based or pheromone fragrance. As long as the by catch of non-harmful species is small it is an environmentally friendly fly-killer.