Silverfish & Firebrats

August 15, 2009

SILVERFISH AND their heat-loving firebrat cousins attract surprisingly little research interest despite being major worldwide pests and chewing up rare book and paper collections along with food and textiles. But University of California, Riverside, entomologists are developing a renown for venturing into overlooked urban and domestic pest control realms. For her UCR Masters thesis, Mirtza Millard, an accomplished SciFi and Fantasy book illustrator, followed in the 17th-century footsteps of English microscope pioneer Robert Hooke. Hooke’s 1665 book Micrographia featured a lavishly illustrated chapter titled “To the small Silvery Bookworm.”

Millard, who is leaving behind Riverside firebrats and silverfish to study Texas ants, recommends baiting and trapping strategies rather than conventional pesticide sprays. Though pyrethroid and diatomaceous earth insecticides are often helpful, silverfish and firebrats may be repelled and go into hiding in cracks and crevices when surfaces are sprayed with conventional pesticides.

Fipronil, carbaryl or avermectin formulated into egg noodle and dog food baits work well against firebrats in lab tests; boric acid, indoxacarb and imidacloprid were not so effective. Conventional ant and cockroach baits (e.g. hydramethylnon) may be tasted (scraped on the outside), but are ineffective because they are not eaten. At UCR, Millard found that small particle (0.25-0.4 mm) baits made from grinding up high-protein egg noodles worked better than large particle and starchier baits.

Millard traps these wingless, crawling insects in small glass jars ringed with a sticky surface on the outside to make it easy for the pests to crawl inside. Once over the top of the jar, the insects lack wings to fly and cannot crawl out over the steep slick glass surface. It is similar to when silverfish seeking moisture and humidity get trapped in bathtubs and sinks and futilely try to crawl out.

Jar traps are best placed near cracks and crevices and in corners near foraging sites. It takes trial and error to master trap placement and figure out foraging sites. So try placing the small glass jar traps in different corners and near cracks and crevices until the best trap placement is learned. Numbers trapped may be small, as the insects cluster together mainly to mate, lay eggs and keep warm (via body heat) when it is cold.


Coffee Grounds for Mosquito Control

August 2, 2009

RECYCLE BIODEGRADABLE coffee grounds and simultaneously knockdown mosquitoes vectoring dengue, yellow fever, West Nile virus, malaria and other diseases. Hermione Bicudo at Universidade Estadual Paulista in Sao Paulo, Brazil, has been working towards that goal since the early 1980s. Mosquito control alternatives are needed, as mosquitoes are rapid, prolific breeders that rapidly develop resistance to pyrethroid, organophosphate and other types of insecticides.

Bicudo’s lab began studying caffeine effects on Drosophila fruit flies in the early 1980s. Drosophila fruit flies are a model insect widely used from the early twentieth century to unravel the mysteries of inheritance and genetics. Caffeine has been used relatively safely for centuries, and is found in medicines, cosmetics and food and beverages like coffee, tea, guarana and chocolate. Used coffee grounds are a ubiquitous waste product in modern caffeinated societies.

A resurgence of yellow fever mosquito, Aedes aegypti, in Brazil prompted Bicudo’s lab to test whether deleterious caffeine effects on Drosophila fruit flies (e.g. less frequent mating, less egg laying capacity, shorter life spans) might also slow mosquito population growth. Approximately four full soup spoons of used coffee grounds in a 250 mL glass of water killed 100% of aquatic mosquito larvae. This translated into fewer adult mosquitoes (the biting, blood-sucking stage) and less new mosquito egg laying (thus, lower mosquito populations over time). Used coffee grounds also have fertilizer value for plants, and can be dusted onto Bromeliads and other garden plants (possibly also puddles, ponds, tree holes, used tire breeding sites, etc.) where accumulated water forms potential mosquito breeding sites.

In contrast to other researchers, Bicuda’s lab found that caffeine solutions became more effective against mosquitoes with age. Day-old caffeine solutions took 20 days to kill 100% of mosquito larave; 25-day old caffeine solutions killed 100% of mosquito larvae in 1 day. Combined with elimination of mosquito breeding sites, used coffee grounds or caffeine solutions could prove very useful in IPM (integrated pest management) programs to slow pesticide resistance and reduce mosquito breeding.