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One of the not-so-delightful tasks of property management is dealing with unwanted pests. Learning of a cockroach infestation can be a bit overwhelming for anyone, but especially in a multifamily environment where pests can spread quickly from unit to unit.

Cornell University's Susannah Krysko, an integrated pest management researcher, recently shared tips on how to approach cockroach infestations in multifamily and strategies to manage prevention in a webinar through The Northeastern IPM Center and StopPests in Housing hosted by HAI Group.

Kysko shared details on how Integrated Pest Management (IPM) is the safest and most effective way to control cockroaches in multifamily housing. The cycle of IPM includes inspecting and monitoring; identifying a potential infestation; scaling the response; using multiple tools to address the issue; and evaluating success. Because cockroaches are a health hazard that can cause asthma and allergies, and contaminate food, dishes, and counters, it’s incredibly important to quickly address an infestation.

While hard to detect as they often hide in undetectable cracks and crevices, a sure sign of an infestation is frass left under cabinet shelving, atop doorways, or along baseboards. Krysko said that cockroaches prefer to live near water, food, and warmth nearly anywhere in a building. Hidden leaks can be a significant issue in an ongoing infestation, Krysko pointed out, as cockroaches need water to survive. They find water sources from leaks, sinks, pet bowls, shower stalls, sweaty pipes, AC units, refrigerator drips, and pans or gaskets.

Trash chutes and boiler rooms are often areas in multifamily housing where cockroaches can thrive in addition to individual units. If unaddressed, one pregnant cockroach can multiply into 18,400 cockroaches in the matter of six months, Krysko shared. Sticky traps placed near areas where cockroaches may travel is a great start in monitoring. If detected, she recommended multiple tools to begin the process of removing these unwanted pests.

This begins with sanitation of the infested residence; eliminating harborage or clutter that cockroaches can hide in; excluding access points by sealing or fixing cracks, loose moldings, holes, and plumbing; vacuuming visible pests; and implementing targeted chemicals administered by a licensed professional.

Bait gels applied by a licensed professional are effective in killing adult cockroaches as well as the hiding nymphs that will then feed off the poisoned adults. Baits are also considered a prevente measure superior to routine spraying. Insect growth regulators that interfere with growth and egg hatching are also effective as well as insecticidal dusts, but Krysko steers against over-the-counter sprays and foggers as these are not compatible with baits and cockroaches can develop resistance to these chemicals.

Follow-up treatments are then scheduled every two to four weeks depending on the severity of an infestation. For on-site teams hoping to prevent infestations to begin with, Krysko recommended personnel to conduct monitoring and inspections, sanitation when needed, and routine exclusion practices, and prompt repairing of leaks.

Krysko noted these questions as points to review on a property’s pest management contract:

  • Does your pest management professional (PMP) use sticky monitors?
  • How often does the PMP check the monitors?
  • Is a yearly or quarterly inspection included?
  • What tools are used in treatment?
  • Will the PMP visit every two to four weeks until an infestation is eliminated?

StopPests in Housing, which receives funding from the Department of Housing and Urban Development, is dedicated to improving pest control in affordable housing by teaching everyone who works or lives in housing how to use integrated pest management.