Breaking the life cycle: Insect growth regulators (Coopers)

Nici de Beer

Coopers Environmental Science

Minute insect, major pest! One ant is not much of an enemy, but oh how a colony can rampage your kitchen! Insects are small and almost insignificant, but their power lies in numbers and together they are difficult to beat. This is no easy task and a full arsenal of insecticides is required to win the battle. The enemy in your kitchen has adapted to survive (or rather thrive) and can reproduce at an alarming rate.

Population growth

Most insects have a large reproductive capacity. This increases the likelihood of mutations which could lead to adaptations and improves the chances that the species will survive in the future. Other factors that influence population growth are food availability and the presence of predators. If a large amount of food is available and a population is not kept in check by natural predators it will lead to population growth. Unfortunately, with insects’ high reproductive rate, this can quickly lead to a pest outbreak if left unchecked.

Breaking the life cycle

Two major insect life cycle types are identified. The first one is holometabolic which means they undergo metamorphosis, for example a caterpillar to a butterfly. The second type is hemimetabolic, in which case they do not undergo full metamorphosis and the juveniles are only smaller versions of the adult.

Insects such as flies (e.g., housefly, bluebottle fly or vinegar fly) are holometabolic and have the following stages in their life cycle: egg, larvae, pupae and adult. When focusing on flies specifically, the adult stage is the most difficult to control since flight gives the adults the freedom to move faster and further than any of the other life cycle stages.

When controlling an outbreak of flies, one would look at breaking the life cycle before the adult stage, since the adults would be the most difficult to control.


Insect Growth Regulators

Insect Growth Regulators (IGRs) are substances that give us the ability to do exactly this – break the life cycle. It works by disrupting the chitin formation during moulting in the juvenile stage of the insect by manipulating insect-specific hormones.

These substances have a different effect on each of the stages within the life cycle, for example, the adult stage will not be affected, but the eggs they produce may not survive. Eggs that come into contact with IGRs might not hatch and the juvenile stages will not develop correctly. IGRs will be effective on many insect pests such as flies, cockroaches, and mosquitoes.

IGRs can form part of an Integrated Pest Management system, together with sanitation practices and pesticide rotation, which helps to combat resistance to conventional insecticides.

Larvakill SC

An excellent option is the Coopers Environmental Science product Larvakill SC (L 10230), an IGR containing diflubenzuron.

It is registered for use on cockroaches, fly maggots, flea larvae, mosquito larvae and litter beetle larvae and thus provides a solution to multiple problems. It contains the active ingredient diflubenzuron, a member of the benzoylphenylurea (BPUs) insecticides.

Diflubenzuron was the forerunner of its kind and has been broadly studied and used across the world. Studies on diflubenzuron showed low toxicity towards mammals, birds and fish, which makes it a more environmentally friendly product than many of the others available.

The Suspension Concentrate (SC) formulation of Larvakill SC is a modern formulation type where the active ingredient is suspended in water.

Since water is used as the solvent Larvakill SC does not have a strong smell when compared to Emulsifiable Concentrate (EC) formulations.

Additional benefits of an SC formulation include ease of use, dust free and effectiveness.

Larvakill SC can also be used in conjunction with Deltakill CS (L9528) to pack a powerful punch! In combination Larvakill SC breaks the life cycle through its effect on eggs, juveniles and pupae and Deltakill CS serves as the adulticide.


Larvakill SCfor fly control should be applied to the following areas:

  • Manure heaps;
  • Refuse bins;
  • One-meter-wide perimeter spray of interior walls and floors in animal housing buildings; and
  • Runoff areas: Flies breed in moist organic material, g., where animal housing’s floors are washed and the water accumulates in a holding area outside.