[Cockroach Control Issue] Next Generation of Cockroach Control

Before the use of baits became commonplace, cockroaches were the No. 1 cause of callbacks. The ability to effectively control cockroaches was a sign of a pest management professional’s expertise, because treating cockroaches with traditional contact insecticides required much more time and know-how. Still, insecticide resistance could challenge even the most experienced pest management professionals.

Modern roach baits arrived on the scene in the mid-1980s and leveled the playing field, achieving tremendous results against cockroaches in pest management professionals’ toughest accounts. Even inexperienced technicians could solve a tough cockroach problem, making it a very profitable business for companies willing to offer roach control with baits.

Over several years of steady growth, baits became the preferred formulation for roach control because of their superior efficacy and because they allowed for applications in critical areas without disrupting a customer’s day-to-day life and business operations. Consequently, a variety of new gel baits came to market and eventually a serious issue emerged.

In the early 1990s, pest management professionals began to report problem accounts where German cockroaches had stopped taking the bait. Maxforce researchers determined that cockroaches were avoiding a specific food ingredient common to many commercially available baits. They isolated the culprit, glucose, and substituted fructose to solve the bait-aversion problem. There was no insecticide resistance issue associated with the control failure in these accounts.

But by 1999, German cockroaches changed their tastes again. Working with hundreds of pest management professionals across the country, Maxforce researchers determined that German cockroach bait aversion had re-surfaced. Most of these cases were in food-handling establishments with poor sanitation and where pest management professionals were relying solely on gel baits for control. Similar to the first documented cases of bait aversion, the most recent cases involved an avoidance of certain ingredients commonly used in commercial gel baits. In tests, a variety of different cockroach strains showed feeding aversion to all commercial gel baits available at the time, creating the need for a new solution. In 2004, Bayer solved the problem of aberrant-feeding cockroaches again. At the time, many in the industry commonly confused behavioral avoidance with insecticide resistance — a misconception that still occurs today. Simply speaking, however, it is not the active ingredient in bait that roaches avoid, but rather the inert ingredients that used to be attractive to them (i.e., glucose).

For example, pest management professionals have reported cases of control failure even after trying a number of commercially available baits. This classic “rotational strategy,” which could work well against insecticide resistance issues, was not working against behaviorally finicky eaters. Why? Different commercial baits can contain the same feeding-averse ingredients, even though their active ingredients are different. Our industry has learned the hard way what we now understand clearly: Without truly knowing what ingredients roaches have come to avoid, pest management professionals trying to rotate various baits on the market are unlikely to achieve lasting control.

Ever since the aberrant-feeding behavior mechanism was first discovered about 15 years ago, Maxforce researchers have worked with hundreds of pest management professionals across the country to tackle difficult infestations. They have continued to rear the offspring of the strains collected from these accounts to “predict” the aberrant-feeding behaviors cockroaches will exhibit next. Understanding that roaches will only become even pickier eaters as time goes on, it became clear to Bayer Environmental Science that the professional pest management industry was in need of a bait that didn’t rely solely on ingestion as the primary mode of action.

NEW COCKROACH CONTROL. Years of research at Bayer Environmental Science have yielded the next generation of cockroach control with an enhanced killing power, giving aberrant-feeding cockroaches little to no chance of surviving a bait treatment, as Bayer Environmental Science’s studies have shown.

Maxforce FC Magnum is formulated with five times the active ingredient, fipronil, providing contact, ingestion and secondary kill. Increasing the active ingredient in the new gel bait is a strategy that will help prevent bait aversion from developing and spreading in problem accounts, according to Bayer ES research. With this scientifically calibrated level of fipronil, plus an advanced formulation technology, cockroaches no longer need to consume the bait to die; they simply need to touch it, which Bayer calls ContactX technology.
The bait matrix was specially designed to be attractive and consumed by both normal and finicky cockroaches, though an actual meal is no longer required to achieve control.

To prove that no bait consumption is required for cockroaches to die, Bayer researchers sealed cockroaches’ mouthparts with paraffin wax and exposed them to the gel bait in a standard test arena (also known as an unforced contact test protocol), so the death of cockroaches could only be attributed to the contact kill.

Maxforce FC Magnum also has a magnified domino effect, a delayed-action kill that occurs as intoxicated cockroaches live just long enough to transfer the active ingredient to others.

One of the many advantages of fipronil is its control of cockroaches whether by ingestion, contact or domino effect. And because cockroaches no longer need to consume the bait to die, only touch it, pest management professionals can simply apply bait to high traffic areas where roaches move through, such as corners, against walls and at the entrances of cracks and crevices, to increase exposure and contact kill. Also, the bait stays moist and potent, even as it ages.

CONTROL MEASURES IN THE FIELD. Even with all of the available tools in pest management professionals’ toolboxes, effective German cockroach management should still include an integrated approach, such as:

• Vacuuming and trapping to “crash” populations.
• Focusing on floor-level sanitation prior to product application in order to remove competing food sources.
• Considering residual sprays around the perimeter and dusts in deep harborage voids.
• Having your customers record on a “sighting sheet” where they observe roaches to give you a road map for bait placement.
• Sealing cracks and crevices as an added service that provides value, increases revenue and reduces roach hiding spots.
• Installing roach bait stations to maintain control.

The author is the leader of Professional Pest Management Biology at Bayer Environmental Science. He can be contacted via e-mail at nbao@giemedia.com.