In the early 1900s, for instance, insects and parasitoids were sometimes released after little testing on nontarget effects. As a result, the biocontrol agents often found meal sources that were more appetizing than the ones they were supposed to eat—and sometimes became a threat to a native insect or plant.

To combat the gypsy moth in 1906, for example, the parasitoid Compsilura concinnata was released in North America. Scientists knew that C. concinnata was polyphagous (pursued multiple hosts) but though that their variable appetite would ensure greater success in controlling the moth pest. Instead, C. concinnata attacked several native moths, including giant silkworm.

Florida cactus inadvertently became the preferred diet of Cactoblastis cactorum, released initially in Australia in 1926 to control prickly pear. The predator moth was so successful at lowering the prickly pear population in Australia that scientists released it in 1957 on Nevis Island in the Caribbean, close enough to the Florida coast for the moth to travel to the state and feed on several native cacti species, one of which it extinguished.

More recently (1990) a European thistle weevil, Larinus planus, was released into several western states to control Canada thisle.  By 1999, L. planus was feeding on a rare thistle species in Colorado, while ignoring the Canada thistle growing nearby.

Evens such as these led scientists to adopt new practices that would limit the chances of a biocontrol agent to attack a nontarget population. Scientists introducing biocontrol agents for weeds must present, to a federal panel, a detailed plan for host range testing based on specified protocols.

Procedures for testing biocontrol agents for insect pests do not involve a federal panel, but scientists often carefully screen close relatives of the target organism to see if the biocontrol agent will attack it, given no other food option. Organisms that adapt readily to hosts other than the target are typically rejected for use.

However, each organism presents its own risks as soon as it is released into the natural environment. In the controlled environment of a laboratory, with a limited time period, scientists cannot observe or predict how an organism may adapt over a period of years, after it has reproduced several generations and adjusted to its new climate and surroundings. The question asked is always, “do the benefits outweigh the risks, or are the possible consequences not worth the risk?”

Contrary to my usual conclusions, I’m not going to make one in this argument. I want to let those who are interested to guide the discussion. You may be a passionate advocate of biocontrol. Or you may have seen some of the past damage and now fear every biocontrol implementation. As is true with many IPM practices, there are no universal right or wrong answers. Each scientist must decide how to handle each case individually and decide what may work for today.

In the downtown Eastside community of Vancouver, people live in overcrowded, unsanitary conditions. Poverty, homelessness, drug use and HIV/AIDS incidences are high. From this community, researchers C.F. Lowe and M.G. Romney examined bedbugs recovered from three patients in nearby St. Paul’s hospital. One of the patients was suffering from methicillin-resistant Staphylococcus aureus (MRSA) and two patients were suffering from vancomycin-resistant Enterococcus faecium (VRE). Lowe and Romney found MRSA in three bedbugs collected from the one patient and VRE in one bedbugs collected from the other two patients. According to the paper, the patients were infested with bedbugs.

As with glyphosate-resistant weeds, bacteria that is resistant to one antibiotic are often susceptible to others. Both the MRSA and VRA bacteria isolated from the bedbugs were susceptible to other antibiotics, including clindamycin, tetracycline and trimethoprim, commonly prescribed antibiotics in the US.

Although authors state that the results point to the potential of bedbugs to act as vectors of bacteria transmission, several factors may have contributed to that potential in the three patients. First, the patients lived in an area where 31 percent of residents have reported bedbug infestations (a very high percentage).

Second, both VRE and MRSA rates in the community are high. MRSA has been found in 54.8 percent of patients at St. Paul’s Hospital, and 43 percent of drug users in that community have had a strain of MRSA unique to that community. Authors attribute the high rates of VRE to the squalid conditions, since enterococci bacteria inhabit the gastrointestinal tract and can be transmitted through food. The authors do not state that the three patients may have been infected through bedbug bites. Rather, they state that the conditions of the neighborhood—especially the overcrowding and drug use, that can leave openings in the skin—may contribute to any potential for infection by bacteria transmitted by bedbugs.

While the results of this research may counter previous assurances that bedbugs—although undesirable—are medically harmless, it supports other general findings about the relationship between insects and bacteria. Insects that walk on bacteria-covered surfaces can potentially pick up bacteria on their feet and carry it elsewhere. Insects that feed on blood can potentially ingest bacteria-ridden blood and inject it in another donor. However, in this study, although bacteria were isolated from bedbugs, the authors did not find that the bedbugs vectored those pathogens to someone else.

Probably the most important lesson is on how to protect yourself from insect-borne infections in general. Here are a few tips on how to prevent infections, whether from an insect bite or from your environment in general:

• If you live in an area with a high incidence of insect-vectored diseases (such as Rocky Mountain Spotted Fever, Lyme’s Disease, malaria, etc.), wear bug spray while outside or avoid highly shaded and consistently moist areas as much as possible. We’re not advising you against a good camp-out, but please be safe and check for ticks as often as you can. Most bug sprays keep other biting insects away, such as mosquitoes and chiggers.
• Always cook food thoroughly according to food safety guidelines. Not sure what those are? Go to FDA.gov or FSIS.gov. They have several resources for homeowners.
• Keep your living conditions as clean as possible. No need to become a clean freak, but be sure that your kitchen counters, cooking utensils and appliances pots and pans and dishware are cleaned with soap or other cleansers before use.
• If you do have an insect infestation, call your local extension office first. Although you will probably need to have an insecticide treatment, a person trained in integrated pest management can help you prevent another infestation by making some small changes around your house. Finding openings in crawlspaces, around windows and doors and through outside walls can be invaluable to keeping pests out of your house—except for the ones that follow you into the house when you come in the door.
• If you have a rash or insect bite that itches, use an anti-itch treatment on it rather than scratching. Scratching can create open wounds that can allow bacteria to enter, regardless of pest presence.

The results of the bedbug study will hopefully invite and produce more research that will further examine the potential—or lack of potential—of bedbugs to vector disease.

The Blog-Health-o-Meter™ reads This blog is on fire!.

Crunchy numbers

A Boeing 747-400 passenger jet can hold 416 passengers. This blog was viewed about 13,000 times in 2010. That’s about 31 full 747s.

In 2010, there were 54 new posts, growing the total archive of this blog to 71 posts. There were 67 pictures uploaded, taking up a total of 7mb. That’s about 1 pictures per week.

The busiest day of the year was February 25th with 238 views. The most popular post that day was Venerable NY IPM Program On the Ropes.

Where did they come from?

The top referring sites in 2010 were sripmc.org, pest.ceris.purdue.edu, insectsinthecity.blogspot.com, google.com, and twitter.com.

Some visitors came searching, mostly for lionfish, bed bugs concern, kudzu bug, lion fish, and ccd bees.

Attractions in 2010

These are the posts and pages that got the most views in 2010.

Venerable NY IPM Program On the Ropes February 2010
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Invasive Species in Aquatic Habitats – Altering the Predator-Prey Balance August 2010

Lionfish: A new delicacy, or an increasing threat? September 2010

Bed Bugs: An Increasing Public Health Concern August 2010
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Killing bed bugs in your laundry March 2010
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