Cockroaches are an important public health pest. They have been implicated in the transmission of several pathogenic organisms, can cause allergic reactions and trigger asthma attacks. They are also a prolific cockroach species, producing four to eight generations per year.
Insect growth regulators (IGRs) can be useful tools to help break the life cycle of these prolific pests, as well as many others. IGRs, such as pyriproxyfen, mimic the juvenile hormone that naturally occurs in an insect. This hormone controls how long a cockroach remains in each nymphal stage and when it turns into a reproductive adult. IGRs prevent the normal development of immature cockroaches so they cannot produce viable eggs as adults or die during the molting process.
As IGRs don’t kill insects quickly, they are often incorporated with fast-acting insecticides or baits. When using baits, it’s important to remember that not all cockroach stages feed on bait with the same appetite level. Typically, adult males readily forage for food and leave harborage points.
On the opposite end of the spectrum, gravid (pregnant) females are much less active than other cockroach stages, preferring to stay close to harborage points, and significantly reduce their feeding and drinking. This means there is a lesser probability of gravid females eating bait than cockroaches in other life stages.
IGRs can cause egg cases to release prematurely, stimulating a female to return to normal foraging and feeding patterns. Therefore, an IGR is most effective when applied as a crack-and-crevice treatment to cockroach harborages, increasing the probability that cockroaches in multiple life stages, including gravid females, will actually contact the product. Because each egg case is carried by a female cockroach for about three weeks until the eggs emerge, a direct application of an IGR can provide an advantage in the amount of time required to control a population.
Adding IGRs to your cockroach control program can help reduce populations. For more information about IGRs, visit SyngentaPMP.com/Archer
or contact your local Syngenta territory manager.
Nicky Gallagher, Technical Services Manager, Professional Pest Management, Syngenta
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