Insect Growth Regulators

One of the most frustrating parts of pest infestations are the pest's ability to reproduce and multiply so quickly. Effective pest management programs are those that reduce the likelihood of reinfestations, thus saving money by reducing the need for reapplications of pesticides. One chemical that is an effective aid in controlling the pest population long-term are Insect Growth Regulators or IGR for short.

On this page, we will cover what an IGR is, how it works to eliminate repopulation and its benefits. You can also use this page to shop our top IGR product recommendations.

What are IGRs?

IGR stands for Insect Growth Regulator and is a chemical substance that detrimentally effects the life cycle of insects such as cockroaches, fleas, bed bugs, mosquitoes and pantry pests. IGRs are not able to kill adult insects. Instead, they help to prevent insects from reproducing, stop eggs from hatching and make nymph and larvae unable to proceed to the next stage of their development. Thus, as their name states, they regulate the growth of insects.

IGRs can either come in the form of a stand-alone product such as an aerosol spray, concentrate, or disc. IGRs can also be mixed with other insecticides that kill adult insects so the entire life cycle is targeted.

Some of the more popular active ingredients that are regarded as IGRs include Hydroprene, Methoprene, Novaluron, and Pyriproxyfen.

How Do IGRs Work?

Insects go through either a gradual or complete metamorphosis before reaching adulthood. These stages vary from egg to nymph or larva, to pupa and then finally adult. IGRs work by mimicking an essential hormone in insects that cause molting to take place. It is through the hormone mimicry that they are unable to progress into the next stages of their development.

For example, when an insect such as a cockroach or bed bug is in the nymph stage of development and comes into contact with an IGR, they become stuck in that stage of development and will be unable to grow. Their reproductive organs don't develop so they can't lay eggs or make babies. In cockroaches, this is often visible in the roach looking deformed and wings appearing broken. The insect becomes sterile, breeding can not take place and multiplication stops.

IGRs can also cause eggs that are waiting to hatch to be unable to hatch. Other IGRs, like diflubenzuron, are chitin synthesis inhibitors. These insect growth regulators work by interfering with an enzyme called chitin synthetase, resulting in disrupted molting and development.

Benefits of IGRs

Insect Growth Regulators are a helpful chemical and in many cases are vital to putting the stop to an infestation since it takes away the ability of an infestation to continue to multiply.

IGRs work quickly and most IGR products are long-lasting so you don't have to apply them often. Some IGRs can remain effective in the area where they were applied for up to 7 months. IGRs are odorless and can be applied in areas where food is handled or stored without an issue. Most IGRs are photostable, have low volatility, and have low toxicity to mammals, birds, and fish.

IGRs can move into areas that have not been treated, which is great for pests that are hiding in hard-to-treat areas like wall voids, behind equipment and other areas.

Drawbacks of IGRs

IGRs on their own do not kill insect populations, namely already developed adults. For adults, you will need an adulticide. IGR works best when it is combined with an adulticide so eggs, nymphs and adults are all addressed.

IGRs can harm beneficial insects such as bees, so you should be careful in where you apply it to reduce the chances of the IGR affecting non-targets.

Are IGRs Safe?

IGRs are low in toxicity to humans and animals and are safe to use when applied according to the label directions. Exercise caution by wearing the proper personal protective equipment in the form of gloves and protective eyewear before mixing and applying the IGR products.

What To Expect

When applying an IGR, you should monitor the pest situation or observe the specific pest to see if there are changes in behavior and activity. For instance, if you notice cockroaches crawling around that look deformed, that means that IGR has affected them and the product is working. Use IGRs in combination with adulticides and you should see a sharp decline in insect activity. With no reproduction taking place, the population is unable to regenerate and so they will die off totally.

When using an IGR alone, it may take 4 to 6 months for an infestation to die out as the remaining adults will eventually die of natural causes. For very severe infestations of pests, you may need to do repeat applications of IGR more often until you observe less insect activity.

Featured Products

Novacide Aerosol - Novacide Flea and Tick Killer is an aerosol insecticide with the IGR Pyriproxyfen. Though primarily used for controlling fleas and ticks, Novacide can also be used against many other insects such as roaches, moths and ants. Novacide is safe to use and kills with contact.

Gentrol Point Source - Gentrol Point Source IGR uses Hydroprene and is an easy to use Insect Growth Regulator that effectively breaks the life cycle of targeted pests. It can be effective for up to seven months, offering long-term control of cockroaches and some stored product pests. 

Martin's IG Regulator - Martin's I.G. Regulator is an insect growth regulator concentrate using Pyriproxyfen. It provides effective long-term control of fleas, roaches, flies, mosquitoes, gnats, crickets, litter beetles, and ants. The IGR works as a type of population control for insect invasions.