Union Democrat

Cockroaches: The ever-changing household pest

As Halloween approaches, our thoughts turn to creepy-crawly, bats-and-spiders, fallen-leavesin-cemeteries musings. One of humankind’s least favorite creepycrawly critters is the household cockroach, Blattella germanica.

According to the University of California Integrated Pest Management Program (http://ipm. UCANR.EDU/PMG/PESTNOTES/ pn7467.html), the German cockroach is the most common indoor cockroach, especially in multi-unit housing environments. They love kitchens and bathrooms, preferring warm, moist environments that provide food, water and dark places to hide. An adult German cockroach can hide in a crack 1/16 of an inch wide.

Even though cockroaches do not bite humans, they are implicated in a number of health problems. In her Halloween-worthy book, “Wicked Bugs,” author Amy Stewart tells the story of a 1940s housing project in Southern California that, by the 1960s, became the source of 40% of Hepatitis A cases in the area. When UCLA scientists developed a silica dust insecticide that destroyed the cockroaches’ cuticle (“skin”) and tested it in the housing project, 70% of all cockroaches were killed. Hepatitis A cases were almost eliminated in the housing project, while they continued to increase in the surrounding community. German cockroaches, shuttling between garbage, food and human waste, are believed to be capable of transmitting staph, strep, Hepatitis A and E. coli. They have also been implicated in the spread of typhoid and dysentery. Amy Stewart adds salmonella, leprosy, plague and hookworm to that list.

However, in his book, “Never Home Alone,” ecologist and

North Carolina State University Professor Rob Dunn says that cockroaches, even though they can carry pathogens, pose much less of a disease threat to humans than humans do to themselves. We routinely carry and transmit many more pathogens to each other (COVID is a case in point). The most serious cockroach problem is that of allergens, created from regurgitated food, droppings, bits of cast-off skin and egg casings, stains and odors. Half of all people with asthma are allergic to cockroaches. Ten percent of nonallergic people have a sensitivity to cockroaches, ranging from mild to anaphylactic shock. A roach allergy can also cause cross-allergic reactions to shrimp, lobster, crab, crawfish, dust mites and other bugs.

But, unfortunately, our human tendency to resort to chemical warfare to destroy pests we fear and hate has had a rebound effect. Each time we create a new pesticide, cockroaches (and many other pest insects) develop resistance and immunity to it. According to Dunn, the pesticide chlordane, thought to be invincible, was developed in 1948. By 1951, Texas cockroaches were resistant to it. By 1966, roaches were found that were resistant to malathion, diazinon, fenthion, and then DDT. It was discovered that sugar baits laced with insecticide killed most cockroaches, except for those that had an errant gene that caused their “taste buds” to experience sugar as bitter. They avoided the sucrose-based baits and survived. Since mother cockroaches can give birth to all-female offspring without need of a male partner, and since one female cockroach can conceivably create ten thousand descendants in a year, many generations of sugar-bait resistant cockroaches came to be.

The many species of fielddwelling cockroaches are rarely a problem, but if you need to control an indoor infestation of German cockroaches, a many-faceted approach is best. Detect and monitor using sticky traps and glue boards. Store food in insectproof glass or plastic containers. Keep garbage in containers with tight-fitting lids. Remove piles of trash, newspapers, magazines, paper bags, boxes and lumber that provide hiding places. Gel baits are available to treat cracks and crevices. Insect dusts containing boric acid or silica can be very effective but take some time to achieve control.

The best long-term solution may be to return to a better-balanced environment. As Rob Dunn says, “The problem with cockroaches is us.” He recommends de-escalating our chemical warfare and opening our windows and doors to allow the tiny, unseen predator wasps that exist everywhere to come in and find their cockroach prey. This is Integrated Pest Management (IPM) at its best.

Rebecca Miller-cripps is a University of California Cooperative Extension Master Gardener of Tuolumne County.

UCCE Master Gardeners can answer gardening questions; in Tuolumne County call (209) 5332912 and in Calaveras county call (209) 754-2880. Check us out online at wwwcecentralsierra. ucanr.edu/master_gardeners.

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2021-10-20T07:00:00.0000000Z

2021-10-20T07:00:00.0000000Z

https://uniondemocrat.pressreader.com/article/281582358826230

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