Using an insect growth regulator alongside a baiting product achieves excellent results against cockroaches.
With the wide range of cockroach baits and sprays available, many pest managers overlook the benefits of including an insect growth regulator (IGR) as part of their cockroach treatment regime. So why would you include one and which one should you use?
IGRs do not kill adult cockroaches but act on the other life stages, ‘breaking the breeding cycle’. Insect growth regulators are long-lasting indoors and active at very low concentrations, which means they are very effective in preventing re-infestations over an extended period.
There is no known resistance to insect growth regulators, which means they are ideal as a resistance management tool – as they stop resistant populations from reproducing, they prevent the build-up of resistant cockroaches in the population. They are also useful in providing control in cases of bait aversion as well.
As they are non-repellent, IGRs can be used in conjunction with baiting programs. In fact, they have the potential to boost bait performance. Female cockroaches do not feed for the three weeks they carry their egg case. Exposure to an IGR can cause them to drop their egg case and start feeding again, thus speeding up bait performance.
These performance benefits coupled with their favourable safety profile means they are a great option to be used in a spray treatment in conjunction with baits, in sensitive accounts or integrated pest management (IPM) programs.
In fact, in the US, 83% of pest managers use IGRs as part of their cockroach treatments (source: PCT Technology, State of the Cockroach Industry, 2013), with bait treatment plus IGR spray being one of the most popular combinations.
But which IGR should you choose?
There are two types of IGR: chitin synthesis inhibitors (CSI) and juvenile hormone analogues (JHA). Chitin synthesis inhibitors prevent the formation of chitin, which is used to make the cockroach cuticle and ootheca. As a result its key impact on the cockroach life cycle is on the moulting process – cockroaches exposed to a CSI tend to die when attempting to moult. Juvenile hormone analogues regulate the growth and reproductive processes. It is this impact on reproductive processes that make JHAs a very effective active in breaking the cockroach breeding cycle.
Sumilarv, which contains the JHA pyriproxyfen, actually impacts all life-stages of the cockroach.1 Female cockroaches exposed to Sumilarv produce sterile ootheca – the key element in breaking the breeding cycle. Although male cockroaches exposed to Sumilarv also become sterile, the more interesting observation is that males exposed to Sumilarv could transfer the active to the females during the mating process, thus sterilising the female, if she hadn’t already been exposed to Sumilarv.2
Nymphs exposed to Sumilarv are not always killed during the moulting process, sometimes emerging with the ‘classic’ curly wing effect, only to often die during a later moult. But as with the adults, these nymphs are sterile.
Using an IGR is the smart way to deal with cockroach infestations, especially in commercial or sensitive accounts. Sumilarv is not only ideal for inclusion in flea treatments, but is a powerful cockroach IGR as well. With its sterilisation effect, not only does it deliver long lasting performance benefits, you can genuinely make the claim to customers that it ‘breaks the breeding cycle’.
1 Fathour, H et al. (2007). Iranian Journal of Science & Technology, 31(A1), 89-98. Effects of a juvenoid pyriproxyfen on reproductive organ development and reproduction in German Cockroach (Dictyoptera: Blattellidae).
2 Kawada et al. (1992). The Japan Society of Medical Entomolgy and Zoology, 43 (3), 169-175. Effects of pyriproxyfen on the reproduction of the housefly, Musca domestica, and the German cockroach, Blattella germanica.
