Cockroach Control: Proactively Preventing Bait Aversion

Cockroaches are constantly evolving — getting tougher to control, in some cases, as they develop resistance to baits and challenge best practices that pest management professionals (PMPs) follow to control these public health pests. Cockroaches ranked as the second most important pest for a PMP’s revenue in PCT’s State of the Cockroach Market Report. “But more than that, cockroaches have the ability to carry disease, trigger allergies and contaminate food,” says Gregg Wisniewski, insecticide brand manager for Professional Pest Management (PPM) at Syngenta, North America. “They are a public health pest and quite problematic.”

Nicky Gallagher, Ph.D., field technical manager for PPM at Syngenta, who helped launch Advion^® Evolution and Optigard^® Cockroach Gel Baits in July 2017, said she regularly visits research sites where Syngenta cockroach baits are used and tested. “We go into apartments to see the level of cockroach infestations people are dealing with. It’s hard to witness — and it’s not right that they have to endure that,” she says.

“Resistance is an issue for the industry, as cockroaches will continue to evolve,” she adds. “To keep up with the cockroaches, we too must evolve.”

Advion Evolution is an enhanced formulation of the existing Advion^® Cockroach gel bait, originally launched in 2006. With the popularity of gel baits, PMPs have and will continue to face bait aversion, Gallagher points out. “It is important that the baits we develop are attractive to all strains of German cockroaches and other cockroach pest species, yet be differentiated from the original Advion [Cockroach] — a top-notch bait that continues to provide excellent results,” she says.

Advion Evolution has the same EPA registration number and label because the active ingredient, indoxacarb, is unchanged. What’s different is the bait matrix, designed to be more attractive to cockroaches, encouraging more feeding and faster control.

Optigard Cockroach, on the other hand, involves a completely different active ingredient that has not previously been used for urban pest control in the United States, Wisniewski says. Emamectin benzoate affects cockroaches at two different target sites: the chloride channel within the muscle and the nervous system, causing uncontrolled release of chloride ions. “It is effective through ingestion and contact. So, it’s an excellent active ingredient from the standpoint of getting thorough control of the pest population. We have done studies on secondary transfer and found that you can control additional members of the cockroach population in addition to the pests that initially consumed the bait,” he says.

Together, Advion Evolution and Optigard Cockroach provide PMPs with tools for a highly effective rotational control strategy. “Our goal is to be proactive and do whatever we can to introduce products that will allow PMPs to get ahead of potential issues,” Wisniewski says.

EFFICACY TESTING. Syngenta has invested in a comprehensive resistance management program that includes technical support and partnering with Purdue University researchers, who test products in challenging environments and in laboratory settings. Ameya D. Gondhalekar, Ph.D., has conducted field tests using Advion Evolution in public housing sites.

Before making treatments at one site, Dr. Gondhalekar caught up to 300 cockroaches in sticky traps during one night. “Usually, we exclude those apartments from studies because there are so many cockroaches that there are other issues leading to infestation,” he relates. “But nonetheless, since Advion Evolution was a new product, I used it.”

Gondhalekar says he was surprised to discover more than 90 percent control in two weeks. “That was something I had never seen in the past five years with any product. So, that is really promising. Advion (Cockroach) was already a really effective bait, but by changing the formulation, they have made (Advion Evolution) even more effective because it is more palatable and attractive for cockroaches to feed on.”

Gallagher agrees that initial field tests of Advion Evolution are “very promising.” “It has been fun to watch the cockroaches binge on that bait,” she says. “Even though the cockroaches have been feeding before and had alternative food sources, they really go for the bait and get a belly full of it, and what we’ve seen is that leads to faster control.”

She adds, “We are putting these baits in really tough situations and we are getting cockroaches under control.” In the worst-case scenarios, control might be slightly less than 100 percent. But, Gallagher says, “Educating residents and getting them on board with an Integrated Pest Management (IPM) program can help reduce the reliance on gel baits.”

Additionally, Dr. Gondhalekar has conducted several lab trials using Optigard Cockroach. He observed the new active ingredient, emamectin benzoate, causing significant levels of secondary mortality. “We found that with Optigard Cockroach, the product can be transferred from cockroaches that feed on the bait to those that have not fed on it, so you get a higher mortality rate.”

STOPPING AVERSION. Bait aversion has long been a concern in the pest control industry, and the strains of cockroaches that develop it and are resistant to baits present a challenge for PMPs. “To combat bait aversion, it’s important to introduce different matrices that do not include the ingredients (they avoid),” says Wisniewski.

Insecticide resistance can be behavioral and physiological, Gallagher says. Creating products that are highly palatable to cockroaches is “not a guessing game.” Syngenta tests baits against dozens of cockroach strains collected from across the country. Some have been in laboratory settings for a number of years. Others are more recent strains collected from the field with a history of being exposed to a variety of baits. “These are what we would call tough strains,” Gallagher says. “It’s important for us to include those in our evaluations because we really want to challenge our baits.”

The enhanced Advion Evolution “is as effective or more effective than what is on the market today,” Dr. Gondhalekar says. Used together, Advion Evolution and Optigard Cockroach provide PMPs with a rotational strategy that is designed to prevent bait aversion and physiological resistance. The idea is, by rotating baits every three months — the average life cycle of the popular German cockroach — you limit the opportunity for resistance to develop. Dr. Gondhalekar says, “When there is no rotation of products, you can see cockroaches getting much tougher to control at a faster rate. When you keep rotating products, that slows down the process of them developing resistance.”

Gallagher says Purdue University is currently working on research that will result in providing specific rotational strategy guidelines for PMPs. “Their research goal is to help the industry by developing sustainable resistance management programs,” she says.

Given that most cockroaches go from egg to adult in approximately three months, by rotating products on this schedule, PMPs can “thwart the accumulation of resistant genes,” Gallagher says. “Those that are susceptible will consume the bait and die, and their genes will no longer get passed on and the population will be suppressed and then controlled.”

And control is essential from a public health perspective. “Cockroach infestations are really difficult to deal with, and we know there is no magic bullet for any pest that we deal with, so our products are part of the solution and included as part of an IPM program,” Gallagher says.

“These new baits will provide peace of mind that PMPs can protect their customers’ health and safety,” she continues. “Through innovations and the support of the team at Syngenta, it’s our mission to provide product performance for a life uninterrupted by pests.”

Learn more at www.SyngentaPMP.com/CockroachSolutions.

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