A pheromone trap is a type of insect trap that uses pheromones to lure insects. Sex pheromones and aggregating pheromones are the most common types used. A pheromone-impregnated lure is encased in a conventional trap such as a bottle trap, Delta trap, water-pan trap, or funnel trap. Pheromone traps are used both to count insect populations by sampling, and to trap pests such as clothes moths to destroy them.
Pheromone traps are very sensitive, meaning they attract insects present at very low densities. They are often used to detect presence of exotic pests, or for sampling, monitoring, or to determine the first appearance of a pest in an area. They can be used for legal control, and are used to monitor the success of the Boll Weevil Eradication Program and the spread of the spongy moth. The high species-specificity of pheromone traps can also be an advantage, and they tend to be inexpensive and easy to implement. This sensitivity is especially suited to some investigations of invasive species: Flying males are easily blown off course by winds. Rather than introducing noise, Frank et al. 2013 find this can actually help detect isolated nests or populations and determine the length of time necessary between introduction and establishment. (Although any trap can answer the same questions, high sensitivity such as provided by pheromone traps does so more accurately.)[1]
However, it is impractical in most cases to completely remove or "trap out" pests using a pheromone trap. Some pheromone-based pest control methods have been successful, usually those designed to protect enclosed areas such as households or storage facilities. There has also been some success in mating disruption. In one form of mating disruption, males are attracted to a powder containing female attractant pheromones. The pheromones stick to the males' bodies, and when they fly off, the pheromones make them attractive to other males. It is hoped that if enough males chase other males instead of females, egg-laying will be severely impeded.[2]
Some difficulties surrounding pheromone traps include sensitivity to bad weather, their ability to attract pests from neighboring areas, and that they generally only attract adults, although it is the juveniles in many species that are pests.[3] They are also generally limited to one sex.
In recent years, pheromone traps also partook in the digital transformation in agriculture, and agritech companies introduced digital pheromone traps. Also known as Pest Traps, digital pheromone traps are IoT devices that include systems to detect and identify pests in the field. Their main goal is to notice pests and manage pesticide spraying. They involve sticky papers, in-built cameras, and various software systems that enable pest detection and identification. Some pheromone traps, such as Doktar's PestTrapp, utilize machine learning technologies to automatize the detection process for farmers and agricultural businesses. Smart farming practices have adapted using digital pest traps as financially beneficial and environmentally friendly tools.
Though certainly not all insect pheromones have been discovered, many are known and many more are discovered every year. Some sites curate large lists of insect pheromones.[4] Pheromones are frequently used to monitor and control lepidopteran and coleopteran species, with many available commercially.[5] Pheromones are available for insects including: