Friday, February 28, 2014

A reminder about rat bite fever

"Rat bite fever" does not refer to the latest Hollywood horror film.  Rather it is a little known infection sometimes mentioned when listing to prospective clients the reasons why a good rodent control program is so important.  In a sad story this week, however, rat bite fever has gotten some media attention.

USA Today reports that a San Diego family is suing Petco [the national pet retailer] after their 10-year old son died from rat bite fever allegedly contracted after handling a new pet rat. Results of testing by the Centers for Disease Control have apparently confirmed that the purchased rat was indeed infected with the pathogen.

Rat bite fever is caused by a bacterium known as Streptobacillus moniliformis. According to the CDC, people can contract rat bite fever from bites or scratches from infected rodents, such as rats, mice and gerbils, or even just by handling an animal with the disease without a bite or scratch. It can also be contracted by consuming food or drink contaminated with the bacteria. It is not spread from person to person. Antibiotics, such as penicillin, are highly effective at treating rat bite fever, and it is rarely fatal, according to the CDC.

Nevertheless, as the story implies, rat bite fever is not to be taken lightly. Although this case relates to a domesticated rat, it is no less relevant to pest control on the street.  It would be interesting to learn how the pet rat contracted the disease, perhaps from a Norway or black rat infestation in the store or breeding facility.

How many other serious human diseases are there that we glibly recite as associated with the ants, cockroaches, flies and rodents we control?  Until a personal story like this comes along, it's easy to downplay the importance of our profession. But I'm reminded today how important this work really is.

Running from Little Brown Moths

Little brown moths, like this meal moth,
Pyralis farinalis, can pose an identification
challenge to untrained PMPs.
Skill at insect identification is one of the little things that distinguishes the well-trained from the not-so-well trained pest control technician. And one of the pest problems that stop many a technician in their tracks is the so-called, "little brown moth".  Even entomologists are disposed to run the other way when a little brown moth shows up--so much so that bug experts often use the acronym LBM when sorting these insects from other, more interesting creatures.

But it's really not fair to the moths, or your customers, to give up so quickly on little brown moth identification--especially when the moth is an indoor pest. Household moths are pretty distinctive when examined carefully, and with a little practice identification decisions about indoor moths are not that difficult to sort out.

First a little background.  Moths, along with butterflies, are insects in the Order Lepidoptera--one of the largest insect groups, with almost 175,000 known species. Perhaps the most distinctive lepidopterous feature is the membranous wing surface covered with flattened, modified hairs, called scales.  Scales are what give each species of moth or butterfly their distinctive body and wing color pattern. 

All Lepidoptera go through a complete metamorphosis as they develop.  This metamorphosis starts out with the egg and larval, or caterpillar stage.  After the caterpillar is fully developed there is a pupal stage, then the adult emerges. In moths, it is typically the caterpillar stage that causes the most damage to plants or to stored products; although in pest control the adult stage flying indoors can also be a problem. 

The most common indoor pantry
pest is the Indian meal moth, shown
here resting in its characteristic
push-up position.
Your first job when faced with an indoor LBM problem is to determine the source. Is the moth coming indoors from outside, or is there an indoor source of the infestation?  And secondly, is this a food-infesting pest, or is it a clothes moth?  The first question can be answered to some extent by considering the numbers of moths present (outdoor moths should not be common indoors), but also by familiarity with the important indoor moth pests.  The second question is answered by familiarity with the appearance and behavior of the two major species of clothes moths.

Comparison of sizes and wing
shapes of Indian meal moth (top),
Angoumois grain moth, and
clothes moth (bottom).
The most common types of moths found in residential or commercial interiors are pyralid moths. Pyralid moths include the Indian meal moth, Mediterranean flour moth, almond moth, raisin moth and others. These moths all have a relatively short fringe of hairs on the hind wing.  The Angoumois grain moth is a smaller moth with a 1/2 inch (13 mm) wingspan and a long fringe of hairs on its hind wings shaped like a pointing finger (see right).

Clothes moths are the smallest of the moths likely to be found indoors (3/8-inch or 5-7 mm wingspan). They are covered with light brown to golden scales and have a tuft of hairs on the forehead. The hind wings lack a pointing finger shape. Clothes moths do not readily fly, and prefer to scuttle or run. For this reason, clothes moths can usually be ruled out as the culprit when a client reports seeing flying moths commonly indoors.

If in doubt as to the source of an indoor moth problem, pheromone lures can help. Pheromone lures contain copies of the sex pheromones that these moths use to locate mates. Pheromone lures can be placed throughout an account to help pinpoint moth hot spots. Some pheromone formulations for moths are even available as confusing agents to prevent males from finding female hosts (this approach is not effective for clothes moths, as explained in an interesting article just out in Fumigants and Pheromones newsletter).  Pheromone traps are available for many species and Insects Limited is an excellent source for information on selection and technical aspects of pheromone use.  Another commercial source for pheromones is Trécé Inc.

For anyone with deeper interests in stored product pest identification, including detailed keys to stored product pests, an excellent resource is the USDA Agriculture Handbook 655, Insect and Mite Pests in Food, now accessible online.

With all the great resources available there really is little reason to run from those Little Brown Moths.

Friday, February 7, 2014

Mosquito Training for Cities

AgriLife Extension will be hosting four Mosquito Training workshops this spring in Fort Worth (Mar 10), Longview (Mar 14), San Antonio (Mar 17), and Round Rock, TX (Mar 24).  The program is designed to help orient municipal employees who need to learn more about setting up a mosquito control program, but some of the information could be useful to pest management professionals involved in mosquito control.  These workshops are being held along with the Texas Department of State Health Services, and will include DSHS speakers at some locations.

The programs have been developed by AgriLife extension entomologist Dr. Sonja Swiger. I will be helping with the first program in Fort Worth, and Wizzie Brown and Molly Keck will be assisting with the San Antonio and Round Rock location trainings, respectively.  For a copy of the flier, click here.

Topics being covered include:
  • Vector Borne Disease in Humans & Testing 
  • West Nile Virus: Summary of the 2012 Outbreak 
  • Mosquito Identification, Biology & Ecology 
  • Integrated Mosquito Management 
  • Putting Surveillance Data to Work 
  • Properly Treating Mosquito Oviposition Sites
  • Developing an Effective Vector Education Program

Cost for the program is $50 in all locations except Fort Worth, which is free. To register for the Fort Worth program only, click here.  For the other programs contact Dr. Swiger using information on the flier linked above.

Thursday, February 6, 2014

It's not easy finding green

Occasionally I get a request from someone seeking a listing of green insecticides. Of course this is a difficult question to answer without knowing exactly what someone means by a "green insecticide".  Green means different things to different people.  To some it means something natural or organic, overlooking the fact that many highly toxic compounds are found in nature. Others might not restrict a list of acceptable insecticides to only products that occur in nature, but might include some man-modified compounds if they were sufficiently easy on the environment.

Personally I prefer the concept of low impact pesticides. I define "low impact" to include any pesticides (man-made or natural) that pose low risk to humans and to beneficial organisms (including wildlife, pets and beneficial insects).  Using this definition, it's not too hard to find products that fit the description from both the organic and the synthetic side of things.

Examples of man-modified or produced insecticides that meet the low impact criteria include soaps and oils, insect growth regulators, microbial-based products, and reduced risk pesticides identified by the U.S. EPA. If the properties of such products were understood properly, most of these insecticides would be acceptable to most people.

So are there any lists of low-impact, or green pesticides?  A few resources come to mind.  First, Texas has a loose definition of green pesticides in its Green Category products that schools are encouraged to use.  For a summary of these pesticides, see

Another resource is the U.S. EPA list of reduced risk products.  This list is tucked away online in an obscure, online EPA cubbyhole on the Conventional Reduced Risk Pesticide Program.  While this is a regulatory concept and not intended as a list of the lowest risk pesticides, it does list some interesting insecticides that might not be otherwise noted by people seeking lower impact alternatives to more conventional products.  For a list of RR pesticides, click here.

One of the frequently cited sources of "acceptable" pesticides in green circles is the City of San Francisco's Reduced Risk Pesticide list.  The list is designed around professional products that can be used by city employees, and is not intended for consumer reference (click here for consumer low-impact options).  It is, however one of the few sites that has some scientific review and is continually updated with new products--a lot of work.  Municipalities and LEED building architects frequently refer to Tier III pesticides on this site as the standard for acceptable pesticides.

Lastly, the EPA's list of Minimum Risk (or 25b) compounds that are considered exempt from standard label requirements bears mention. This list contains ingredients that are "generally regarded as safe" by the EPA.  Unfortunately, being safe doesn't always make for an effective pesticide; but manufacturers continue to roll out new products with these ingredients because of the economic advantages of not having to register with the EPA.

None of these lists are perfect and all are highly arbitrary in some respects. They all have their uses and limitations.  All of them leave out some very useful pesticides that can solve otherwise intractable pest problems at reasonable risk to the environment. Some "green pesticides" may be very green, but not make very good pesticides--a common problem.  For these reasons, my advice would be to not commit oneself to a course of saying that "only these (select, green, organic, etc.) pesticides will be used" in our city, or our school, or our place of business.

Pesticides are power tools.  Like any power tool, along with their advantages, they have potential hazards. That doesn't mean we shouldn't use them, but that we should choose them and use them with caution.  If you're committed to using pesticides from a green list for your school, city or business, give yourself options. The Texas school regulations and the San Francisco program have both been relatively successful.  But they both allow for exemptions or exceptions for using pesticides not on the preferred lists.  The worst mistake any green pest control program can make is to limit itself so that it cannot effectively or economically respond to all pest problems. That's the quickest way to discredit any green program as impractical.

As Kermit the Frog would tell you, "it's hard to be green".  It's also hard to find the perfect green list of pesticides that will cover all pest problems. Keep this in mind, and these lists might actually help you.