As Dr. Phil Koehler, Margie B. and Dempsey Sapp, Sr. So, Koehler spends a lot of time trying to find viable ways to rid environments of this resilient pest. On the other hand, metabolic and nerve poisons, as well as baits, are effective, but over time, some active ingredients could be lost to current legislation and others to resistance. Pest managers will be left with pyrethrins and pyrethroids, and this scenario could pose some problems. Every strain of German cockroach that we've brought in from the field in recent years has had extremely high pyrethrin resistance.
Nymphs are very difficult to kill with pyrethroids.
It only takes 30 times more to kill males and 20 times more to kill females. With the PBO additive, the pyrethroid is 20 times more effective. Just as with ants and termites, the most fortuitous baits used for German cockroach control are slow-acting. Secondary kill is extremely important. Secondary kill is when insects that did not feed directly on the bait still die.