The Industry’s First Line of Defense: Protecting the Perimeter

To protect the perimeter of a home or business and prevent cockroaches from gaining access, the optimal management program should include exclusion and structural modifications, along with exterior insecticide treatment. Such treatment would include application of a liquid residual as a perimeter barrier band and entry points, and/or a granular bait as a perimeter band, and dusting inside the cracks and crevices and voids of the building, said Rentokil Entomologist and Northeast Market Technical Director Chad Gore.

However, the PMP needs to be sure he or she is not simply relying on insecticides to do the job. As Copesan Technical Director Bennett Jordan explained, "Barrier treatments and application of insecticides to structural voids have been shown to reduce the number of cockroaches invading from the exterior, but they don’t typically have a long residual and may require a generous application. While barrier applications may be a part of keeping cockroaches out, they shouldn’t be considered a standalone option." 

Following are tips for implementing a complete exterior cockroach management program from inspection to elimination.

Identify and Inspect
• Know the cockroach. Understanding the cockroaches in your area, and the seasons during which they tend to emerge in substantial numbers, can give you a head-start on performing barrier treatments and approaching your customers to collaborate to reduce their home’s attractiveness. Thus, to determine the best treatment options, you need to make a species-level determination and use the biology, behavior, and tendencies of that species to formulate a defense strategy, Jordan said.

• Know the site. Along with pest identification comes a thorough inspection of structural deficiencies and assessment of any other factors that may be contributing to the cockroach problem, Jordan added. "It really takes a summation of all contributing factors to decide on the proper course of action." A few inspection tips for often-overlooked areas, as provided by Gore, include: 
- Look for potential harborage spots near the building (stacks of wood, building debris, etc); these should be treated with an insecticide as appropriate. 
- Don't forget about lights on a building that may attract cockroaches. Some are good fliers and will be attracted to lights; a liquid residual treatment around those lights (if accessible) will help minimize a customer's encounter with cockroaches indoors. 
- Sewer systems and storm drains. If there are access points to a sewer system (manhole covers) or storm drains, where you can possibly have American or Oriental cockroaches, a treatment plan should be created for addressing those. 

Involve the Customer
• Before conducting any treatment, the PMP should discuss the situation and planned program with the customer, as this conversation may shift the treatment approach, Gore said. For example, the customer may want greener options, there may be a vegetable garden nearby that could be impacted by drift, etc.
• Discuss the inspection findings on the structural integrity of the building or home. While exterior cockroaches may pose no problem, structural issues enable them to get inside where they are a problem. "Therefore, it can't be stressed enough that maintaining a well-sealed building (i.e., sealing cracks/crevices, pipe penetrations, etc.) is critical to keeping them out where they belong," Gore said.
• "Educate your customer on the cockroaches likely to be encountered in the area and get their buy-in on the management program so that they own a stake in program," he added. "If they don't know or haven't been told what part they play and how they can help, then the control program may be a doomed effort."

Apply Insecticide Treatment
• "The best treatment options are those that get the material to where the cockroaches are, or are expected to be, in order to intercept them before they find their way into the structure," Gore said. This often will include a lower perimeter treatment band on the exterior, with a residual material that has a proven extended life is appropriate.

• Base your treatment on the behavior of the species. For example:
- With burrowing roaches (such as the Surinam cockroach), you would be best served by raking mulch into the ground so that it doesn't just sit on the surface. 
- Liquid residuals can be best for Asian cockroaches as they are often found further out in grassy areas of the property.
- Granular baits are ideal for outdoor use for American, Oriental, or smokybrown cockroaches, and can make the most sense for these cockroaches that are likely resident or transient on the immediate perimeter. 
- Granular baits also can provide diversity in a German cockroach program, offering. different bait matrix compared to gels.

• Additionally, always following all label directions: 
- Using a long-lasting, heat/UV light-resistant insecticide with high weatherability is ideal for quarterly perimeter treatments. 
- Mold- and moisture-resistant bait should be used in damp areas.
- On a quarterly or bi-monthly basis, apply a quality residual or a proven green solution to the foundation, the eaves and in a narrow band around window and door frames and other potential entry points. 
- Then apply a two- to three-foot band to the ground around the perimeter, outside of where the liquid foundation overspray may have landed. 
- Treat any non-perimeter areas attractive to insects such as woodpiles and remote landscape beds

Make (or Recommend) Structural and Environmental Modifications

 • Building out peridomestic cockroaches is your best bet for long-term control, Bennett said. You may not have any control over the level of cockroach pressure from your surroundings so it’s imperative to address access points like missing, defective, or improperly installed door sweeps, astragal seals, and weather-stripping, and seal any gaps around electrical and plumbing conduits. Other tips include:

- Reduce lighting or use indirect lighting to minimize attraction of those that will fly to lights.
- Keep garbage containers as far away from the building as practically possible. 
- Seal everything you can. 

• The PMP also should make recommendations for minimizing or eliminating anything that may be attractive to the cockroach and provide for its basic survival needs of food, water or shelter. These could include:
- Exterior harborage (e.g., a pile of wood too close to the building or dense vegetation, leaf litter, and mulch around the perimeter of the home).
- Moisture and drainage issues (such as leaky faucet or hose, overwatered plants, standing water).
- Cockroach food (e.g., fruit fallen from trees that may need cleaned up frequently, garbage containers without properly sealed lids, debris, etc.).
- Overhanging vegetation or limbs that touch the structure and enable entry.
- Fluorescent or mercury-vapor lights that can attract flying cockroaches (recommend a switch to sodium-vapor or halogen bulbs). 

Finally, Jordan said, "once the IPM program is set; don’t neglect monitoring with glue boards to assess how successful you’ve been and to help narrow down trouble spots."