Microencapsulation

Definition

A formulation technology in which active substances—such as insecticides, pheromones, hormones, or microbial control agents—are enclosed within microscopic capsules of polymer, lipid, or other coating materials. The capsule wall controls the rate, timing, or location of release, protecting the core material from environmental degradation and enabling targeted delivery to arthropod pests or their habitats.

Etymology

From Greek mikros (small) + Latin in- (into) + capsula (small box)

Example

Microencapsulated lambda-cyhalothrin, with insecticide droplets enclosed in porous polymer spheres 10–50 µm in diameter, extends residual activity against crawling insects such as cockroaches and ants by releasing active ingredient gradually as the capsule wall degrades or is abraded.

Related Terms

• controlled-release formulation
• insecticide formulation
• pheromone dispenser
• residual activity
• formulation technology
• encapsulated pesticide

Usage Notes

Distinguished from simple emulsions or suspensions by the presence of a discrete wall material surrounding each core particle. In entomology, microencapsulation is particularly valuable for volatile semiochemicals (e.g., mating disruption pheromones) and environmentally labile biological agents (e.g., Bacillus thuringiensis spores, entomopathogenic nematodes), where unprotected materials would degrade within hours to days. Capsule size, wall thickness, and polymer composition determine release kinetics—ranging from burst release upon contact to sustained release over weeks or months. Not synonymous with macroencapsulation, which produces larger beads or granules visible to the naked eye.