Sewer Cockroaches Targeted for Eradication

Cockroaches in Encino's sewer system will once again be targeted for eradication this fall.

The Board of Public Works recently approved a $49,000 plan to treat 2,941 manholes with an insecticide citywide, including ones along Ventura Boulevard, beginning in November.

The nocturnal pests have been eliminated in about 500 holes in the San Fernando Valley over the past two years with an EPA-approved roach control pesticide developed by Anaheim-based Golden Bell Products Inc.

Company executives expect to treat 100 to 150 manholes a day in the city's sewer system.

Destroying the critters is a routine procedure that protects the quality of life for residents and provides a safe environment for sewer workers, said Barry Berggren, manager of the city's waste-water collection systems division.

"Cockroaches go into the dark, damp location of the sewers and that's where they like to breed, but it's not the only place," Berggren said. "Cockroaches can become a nuisance. They multiply in many different locations…but people generally associate them with a sewer system."

There are 140,000 manholes in the entire city. Along Ventura Boulevard, between Lindley Avenue and Sepulveda Boulevard, 150 to 200 holes are scheduled for treatment. About 6,000 other maintenance holes were treated over the past three years.

In 2005, city officials conducted a sewer roach control pilot program and then switched to using Golden Bell, which developed Insecta, a paint insecticide used only in municipal sewer systems.

"Chemists formulated and combined an insecticide within a polymer chain —think of it as a chain of bubbles hooked together. Inside the bubbles is the insecticide, formulated into the latex paint," said Michelle Webster, manager of Golden's sewer roach-control program. "The way it works is as a roach crawls over the painted surface, the mucus on their feet breaks down the polymer bubbles, so the roach absorbs the insecticide directly into its body. By having this formulation and pesticide encapsulated inside the paint makes it very safe."

The treatment lasts between two and three years. Cockroaches are known to carry E. coli, hepatitis, salmonella and dysentery and asthma antigens.

"They are pretty nasty," Webster said. "Insecta kills off adult species and interrupts the breeding cycle. When the eggs hatch it kills off the baby roach, because the nymphs start crawling over bubbles. They never grow up to be adults and so, therefore, they don't reproduce."

To avoid a problem in your house, don't keep pet food and dirty dishes hanging around the house, experts said. Roaches are attracted to water-dripping air conditioning units and pipes, so fix those leaks. Windows serve as a "freeway system" to crawl into houses, so check those screens. 

Within the state of California, there are seven species of cockroaches. Six can become indoor pests while the seventh called field roaches live in leaf litter and plant debris.

Two main species live in sewers. They are the American cockroach, nicknamed the "sewer" roach, and the German cockroach.

"Different species reproduce in different places. The American female lays egg capsules or casings and attaches the casing to a protected spot for incubation," Webster said. "She doesn't carry the capsules or casings on her back or body."

Residents who see cockroaches coming out of maintenance holes should contact city officials through the 3-1-1 telephone system. Inspectors will assess the problem and treat the area if necessary.