Curbing Cockroaches and Their
A tough and wily adversary, the cockroach has survived countless attempts to
curb its domain and lifestyle. Here, ARS entomologist Richard Brenner loads a
petri dish with an experimental bait to see if American cockroaches,
Periplaneta americana, are susceptible to its allure.
In the fictional movie "Joe's Apartment," lead character Joe
befriends thousands of cockroaches and learns to live in harmony with them. But
in real life, anyone who has roaches tries to get rid of them.
Finding ways is Richard J. Brenner's primary goal. For more than a decade,
the Agricultural Research Service
entomologist at the Center for Medical, Agricultural, and Veterinary Entomology
in Gainesville, Florida, has been working on innovative strategies and tools to
send this ancient pest and the problems that come along with it packing.
"Cockroaches aren't just a social problem, they can also threaten
health," says Brenner, who heads the center's Imported Fire Ant and
Household Insects Research Unit.
Cockroaches may carry pathogenic organisms disease-causing bacteria
and fungi that can be passed on to humans through surface and food
contamination. Salmonella in food is one of the most common life-threatening
pathogens that cockroaches can transmit to humans. But there are other, more
likely, ways these pathogens are transmitted.
Health problems from cockroach-carried pathogens are largely circumstantial,
but that is not the case with allergens. Brenner points out that cockroach
feces, saliva, eggs, and outer covering, or cuticles, left behind on surfaces
contain substances that are allergenic to humans, especially those with asthma
or other respiratory conditions.
Not all cockroaches pose a threat. Of more than 4,000 species in the world,
only a few dwell in homes. The German cockroach, Blattella germanicathe
No.1 indoor insect and the brown-banded cockroach, Supella longipalpa,
are the most troublesome species in the United States.
"Both species are strictly domestic and are therefore most commonly
associated with humans and their structures," Brenner says.
Known in his field as the roach expert, Brenner and his colleagues
have come up with a variety of tactics for combating the infamous insect from
precision targeting, which relies on determining exactly where pests are and
estimating their numbers, to allergen detection kits, to vacuum cleaners all
aimed at reducing cockroach problems and related human health risks.
Brenner's team has confirmed the staying power of cockroach allergens. In
the fall of 1990, the scientists infested an experimental kitchen with German
cockroaches. They removed the roaches in February 1991. In 1996, they found
cockroach allergens were still present.
This prompted Brenner and health care officials from the Arkansas Children's
Hospital Research Institute in Little Rock, Arkansas, and the U.S. Food and
Drug Administration (FDA) in Rockville, Maryland, to join forces under a
memorandum of understanding to identify cockroach allergens and develop
allergen detection technology.
"We're looking at how effective different interventions are at removing
these allergens," says M. Christine Anderson, chief of FDA's Laboratory of
Standards and Testing at the Center for Biologics Evaluation and Research.
"We're planning to study two houses in Baltimore, Maryland, to see how
effective cleaning is at removing allergens. We want to know if people actually
feel better once the allergens have been removed."
Cockroaches on a glass plate are attracted to an experimental bait placed in a
petri dish by entomologist Richard Brenner (right) and technician Tim McCoy. A
patent for the bait, developed jointly by ARS and DowElanco, has been applied
Anderson says evaluating devices for effectiveness in removing cockroach
allergens is important, because people particularly children may be allergic to
more than one type.
"We are trying to detect all of the cockroach allergens that may
potentially be a problem, not just one or two. This is the first time anyone
has tried this approach," she says.
From this research, Brenner and fellow researchers have developed a
cockroach allergen detection kit. The kit is sensitive, measuring as little as
150 cockroach-hour equivalents that is, the residue from six German cockroaches
left on a 4-inch by 4-inch surface for 25 hours.
"This is a great tool, because before you can do anything, you have to
know where the allergens are located," Anderson says.
Teamwork To Reduce Pesticides
It has become increasingly important, because of health and environmental
concerns, to limit pesticide use. Brenner's group has several cooperative
research and development agreements (CRADA) with other government agencies and
commercial firms to develop reduced-pesticide-use technologies.
One of the biggest of these projects is a collaborative effort between the
U.S. Department of Defense (DOD), Environmental Protection Agency (EPA), and
Department of Energy to help DOD meet its pollution reduction requirements.
It's called the Strategic Environmental Research and Development Program
"USDA and DOD have had a long-standing partnership of cooperative
research in the area of pest management, going back more than 50 years,"
says U.S. Navy Captain Herbert T. Bolton. He is research liaison officer with
DOD's Armed Forces Pest Management Board.
"This cooperative research partnership has allowed DOD to participate
in customer focus workshops and has led to cooperative research on priority
pest management issues of interest to DOD," Bolton says.
In 1995, DOD became a partner in EPA's Pesticide Environmental Stewardship
Program and signed a memorandum of agreement with EPA to work toward reducing
pesticide risk and use. This program was started in 1994 by EPA, USDA, and FDA
to enlist public and private-sector cooperation in voluntarily reducing
"DOD has set internal goals of a 50-percent reduction in use of active
ingredients--from the baseline, fiscal year 1993--by the year 2000," says
Bolton. "We are also fully committed to implementing integrated pest
management (IPM) practices in our pest management programs."
In 1996, Brenner's group submitted a 4-year research proposal titled
"Pesticide Reduction Through Precision Targeting" to the SERDP
committee. This responded to DOD's IPM research requirements: Develop a
comprehensive, scientific system for reducing pesticide use while protecting
troops, supplies and rations, facilities, and natural resources from disease
vectors and pests.
"DOD's goal is to use targeted, effective, environmentally sound
methods including education, habitat modification, biological and genetic
control, cultural and mechanical control, and--where necessary--judicious use
of least-hazardous pesticides," Bolton says. "The research efforts
made by Brenner's group will help us accomplish this goal."
Some of Brenner's other cooperative research projects that are focused on
tackling social and health implications of cockroaches include:
· A CRADA with Terminix International Co., of Memphis, Tennessee, to
develop nontoxic strategies for eliminating cockroaches and their allergens.
What came out of this partnership was a recently patented new tool. It consists
of a vacuum device that uses hot, dry air to chase cockroaches from their
hiding places and special disposable filters to capture them and their
allergens. This nontoxic alternative will reduce the amount of pesticides
applied by pest control services, which typically use chemical irritants to
flush out cockroaches.
A CRADA with Colgate-Palmolive Co., in New York, New York, to develop
strategies for eliminating or preventing cockroach infestations in buildings by
using repellents and to enhance indoor environmental quality by reducing
Targeting the Problem
To cut down on allergens, scientists need to control the cockroaches
themselves. This requires knowing exactly where they are.
Brenner has developed a computerized precision targeting system that
determines the location and distribution of cockroaches based on trap counts
and their positions. After entering trap data into the computer, scientists use
spatial analysis to construct contour maps showing the population centers
Entomologist Richard Brenner has developed a cockroach antigen detection system
that allows him to map the distribution of these harmful substances so that
contaminated areas can be cleaned. The antigens are proteins that can cause
asthmatic attacks and other allergic reactions.
Spatial statistical analysis is a procedure that characterizes the spatial
relationships from trap data and then uses them to estimate values between trap
points so the entire pest distribution can be determined. This technique helps
reduce pesticide use by allowing the pest control operator to treat only
pest-infested areas, rather than spraying broadly or fumigating an entire
dwelling. It also facilitates development of IPM approaches that the pest
control industry has been eager for.
"Usually, IPM requires a higher level of training and skill than is
typical for normal pest control operations," says Brenner. "Most pest
control operators typically focus on when and where they expect pests to be
found. But things can change, such as how and where a person stores food or the
addition of new hiding places for pests. Therefore, pests may be in unexpected
areas where the pest control operator may not be looking."
Brenner says that precision targeting, unbiased as it is by previous
observations, helps the pest control operator detect subtle changes in pest
distributions. So "pest distribution can be determined consistently,
regardless of the skill level of the technician," says Brenner.
The technique also allows the pest control operator to assess the efficacy
of the treatments. And the process can be used to measure and spatially
characterize possible risks to health associated with cockroaches, such as
Brenner says precision targeting has broader uses than uncovering where
pests are infiltrating homes,
offices, and buildings. He says it can result in pesticide use reductions of 40
to 100 percent, depending on the pest and the control strategy. It could also
save money by detecting infestation early, "when it's a $2 problem versus
a $200 problem," says Brenner.
DOD plans to use the precision targeting software--still under
development--and technologies in its pest control operations.
"This approach integrates a variety of reduced-risk technologies that
will allow DOD to meet and exceed its pesticide-reduction mandate," says
"Precision targeting will provide the documentation DOD needs,"
Bolton says. "It will provide contour maps of pest distributions and the
attendant risks to health, supplies, and facilities; precise locations where we
need interventions; a measure of post-intervention efficacy; and documentation
of pesticide use reductions."
"But precision targeting's not a cure-all solution to the pesticide use
problem," notes Brenner. "We won't get away from using some
pesticides. Nevertheless, with it, we can use the least amount of pesticides
and only when necessary.
"The idea of precision targeting is to shift emphasis from reactive
strategies after the problem has been established to proactive pest management
that prevents the problem."--By Tara Weaver, Agricultural Research
Service Information Staff.
Richard J. Brenner is
in the USDA-ARS Imported
Fire Ant and Household Insects Research Unit, 1600 SW 23rd Dr.,
Gainesville, FL 32604; phone (352) 374-5855, fax (352) 374-5818.
"Curbing Cockroaches and Their Allergens " was published in
the June 1998 issue of Agricultural Research magazine. Click
here to see this issue's table of contents.