Gentrol Insect Growth Regulators, IGR, Gentrol, Hydroprene

An insect growth regulator is by definition a juvenile hormone mimic, a material that inhibits the growth or maturity of certain insect pests. An insect growth regulator (IGR) is an important pest management tool because it helps to reduce, eliminate or prevent infestations of targeted pests without the use of conventional contact insecticides, thus reducing or eliminating the need for pesticides in homes, hospitals, restaurants, warehouse or any area where certain pests are not welcome.

Hydroprene is an IGR that was first introduced to the pest control industry under the brand name Gencor IGR. Gencor was used to help prevent or control populations of indoor roaches, most commonly used against German cockroaches.

Although the name has changed from Gencor to Gentrol, the active ingredient is still Hydroprene. The label for this product has been broadened to include not only roaches (cockroaches) but also many pantry pests, also known as stored product pests. The only stored product pest that does not react well to Hydroprene is the Cigarette Beetle. This particular beetle is affected by Methoprene, another IGR that is widely used in indoor flea control programs. The Methoprene products used by professional pest control operators are sold under the brand name of Precor.

When cockroaches are exposed to Gentrol (any form or type) people usually report seeing crippled, deformed or otherwise odd looking roaches. These deformities are to be expected. Young roaches (also called cockroach nymphs) have an exoskeleton or outer shell. (Mammals have an internal skeleton or bone structure.) As roaches in their nymphal stage grow, their exoskeleton or outer shell becomes too small to contain the insect. As they reach the limits of their exoskeleton a new, flexible exoskeleton forms beneath the old one and the old "shell" splits open to allow the nymphs to molt. This transition denotes what is called a different instar or stage of development.
In heavily infested homes it is easy to see German cockroaches in their varying stages of growth or instars. Many people misinterpret this as a sign of different kinds of roaches when they are actually seeing one species. Another sight that confuses many homeowners is the different shapes of the roaches. Young roaches or nymphs do not have wings. Once a roach reaches its last instar (becoming an adult roach) wings are present. (An exception to this is apparent in an Oriental Cockroach infestation. While the male Oriental Cockroach has wings, the female of the species does not have wings.)

The Effects of Gentrol (Hydroprene) on Cockroaches

The cockroaches effected by Gentrol look deformed or crippled because they cannot form new exoskeletons and have a difficult time trying to shed themselves of their older, harder and undersized existing exoskeleton. You can often see adult cockroaches whose wings are misshapen or seem to be curling up. These roaches have been exposed to Gentrol and will not survive but for a short period of time.

Gentrol is commonly referred to as an insect growth inhibitor, insect growth regulator or IGR. Another term that can be used is "juvenile hormone mimic" because the IGR does just that: it contains a mimic of the targeted pest's juvenile hormone. Once a roach nymph is exposed to Gentrol, it is literally over loaded with a hormone that keeps the insect from maturing or growing up. If the roach (or other targeted pest) cannot mature, it cannot reproduce. Only adult roaches are capable of mating and producing offspring. Another effect of an IGR on cockroaches is an increased appetite. Pest professionals have found that by using an IGR in the same area where roach baits are in use, the roaches will consume more bait than in areas where baits are used without using an IGR.

There are three different Gentrol products used by professionals and homeowners:
Gentrol Concentrate, Gentrol Point Source and Gentrol Aerosol. Many people (in sensitive areas or sensitive situations) will use Gentrol as a stand-alone product, choosing not to use insecticides in their pest management program. Most people choose to tank mix Gentrol Concentrate with an insecticide or use Gentrol Point Source and Gentrol Aerosol in the same areas where insecticide sprays or roach baits are being used.

Gentrol Concentrate is primarily used in cockroach pest control but is also being used as an extra tool in the control of drug store beetles, confused flour beetles, sawtooth grain beetles and other pantry pests. One ounce of concentrate per gallon is all that is needed for most jobs. Gentrol can be used alone and can also be tank mixed with insecticides such as Cynoff, Demon, Suspend, Demand and others.
Gentrol Concentrate and Gentrol Aerosol are now used to help control drain flies in homes and restaurants. Gentrol Concentrate is mixed with foaming concentrate and applied into effected drains using a professional foaming device. Once the Hydroprene material is forced into drains as a foam, it completely covers the inside of drain pipes, preventing fly larvae from maturing into annoying adult flies that can lay hundreds of fly eggs in the drain.
Gentrol Concentrate Product Description and Ordering Information

Gentrol Point Source devices resemble bait stations used for roach or ant control but they do not contain any material that a roach has to locate and eat. The active ingredient (Hydroprene) is released when the designated spot on the device is pinched or slightly crushed. The IGR which is released is odorless and harmless to people and pets. (The active ingredient is not harmful to mammals, when used as directed but there is a possible choking hazard with the plastic device.)
Place the Gentrol Point Source devices in areas where they will not disturbed by people or pets such as behind and beneath heavy appliances (stoves, refrigerators, freezers, dish washers, ice machines), in cabinets, pantries and closets. Use in areas where cockroaches are known to hide and forage for food and water. Kitchens, dry food storage rooms and receiving areas of restaurants, cafes and schools are examples of areas where German cockroaches enter the structures or where they might forage for food.
Gentrol Point Source Product Description and Ordering Information

Gentrol Aerosol is a crack and crevice product designed to be sprayed into out of the way areas where cockroaches and stored product pests are known to hide or travel. Another application of Gentrol Aerosol is for control of drain flies or other small flies such as Phorid Flies and Moth Flies that breed in drains. This Hydroprene product can be sprayed down drains where the larvae of small flies are feeding. Fly eggs and fly larvae (maggots) exposed to Gentrol cannot fully develop into mature flies, thus breaking the life cycle of the population in treated areas.
Gentrol Aerosol Product Description and Ordering Information

Gentrol IGR

Hydroprene Insect Growth Regulators

The Effects of Gentrol (Hydroprene) on Cockroaches