# Methoprene

Methoprene is a juvenile hormone (JH) analog and insect growth regulator (IGR) used widely in pest control. Classified under Insecticide Resistance Action Committee (IRAC) group 7A, methoprene is an amber-colored liquid with a faint fruity odor. Unlike conventional pesticides that kill insects through toxicity, Methoprene disrupts the development of insects, preventing them from reaching reproductive maturity.
Methoprene does not kill insects. Instead, it interferes with an insect’s life cycle and prevents it from reaching maturity or reproducing. Methoprene functions by mimicking natural juvenile hormones necessary for insect development. Insects treated with methoprene fail to transition from pupa stages to adulthood, effectively halting reproduction and the biological life cycle.
Methoprene is considered a biological pesticide because rather than controlling target pests through direct toxicity, methoprene interferes with an insect’s lifecycle and prevents it from reaching maturity or reproducing.

## Applications

Public Health: Methoprene is frequently employed in mosquito control programs to curb the spread of vector-borne diseases such as dengue fever, malaria. and the West Nile virus. Its larvicidal activity targets immature mosquito stages, breaking the insect's lifecycle. Recent studies on the granular formulation OmniPrene™ G demonstrated over 90% inhibition of adult mosquito emergence for up to 63 days depending on water depth and mosquito species, including Aedes aegypti, Anopheles hermsi, and Culex quinquefasciatus.
Agriculture: Methoprene is applied to protect a range of food commodities such as meat, milk, mushrooms, peanuts, rice, and cereals. In cattle farming, it serves as a feed additive to prevent the breeding of flies in manure.
Veterinary Use: Methoprene is a common ingredient in flea control products for domestic animals, aiding in the suppression of flea populations on pets.
Water Treatment: Methoprene is added to water storage systems to combat mosquito larvae, making it a crucial tool for public health initiatives in areas prone to mosquito-borne illnesses.

## Formulations and Efficacy

Methoprene is available in various formulations, including microencapsulated suspensions, granules, pellets, and briquets. The granular formulation OmniPrene™ G utilizes diatomaceous earth as a carrier, enhancing the delivery and stability of the active ingredient. This formulation allows for better vegetation penetration, reduced UV degradation, and improved persistence in aquatic environments.
Laboratory and field evaluations have highlighted the efficacy of methoprene products. Against Aedes aegypti and Anopheles hermsi, OmniPrene™ G maintained over 90% control for at least 49 days in 30.5 cm of water. Efficacy was further extended to 63 days in shallower water depths of 15.25 cm. For Culex quinquefasciatus, control lasted up to 56 days.

## Health and safety

According to its materials safety data sheet (MSDS), methoprene is a material that may be irritating to the mucous membranes and upper respiratory tract; may be harmful by inhalation, ingestion, or skin absorption; may cause eye, skin, or respiratory system irritation; and is very toxic to aquatic life. The GHS signal word is "Warning", with notes such as "P273: Avoid release into the environment" and "P391: Collect spillage".
Methoprene is suspected to be highly toxic to lobsters. Like insects and mites, lobsters are arthropods.

## Conclusion

Methoprene continues to be a vital tool in pest management strategies across public health, agriculture, and veterinary sectors. Its innovative formulations, such as OmniPrene™ G, provide enhanced efficacy and extended residual control, making it a reliable option for controlling disease vectors and agricultural pests while maintaining a favorable environmental safety profile. Ongoing research and careful adherence to application protocols remain essential to maximize its benefits and mitigate potential environmental risks.