Issue 33

Winter 1994

A Newsletter for the Insect Control & Pest Management Industry

The Sawtoothed Grain Beetle ... I n 1980- 1988 the sawtoothed grain

beetle (Oryzaephilus surinamenis) was listed in a survey of Land Grant Universi­ties throughout the United States as the most frequent stored-product insect sent in by homeowners to be identified. It is one of the top insects listed by processed food companies (processed cereal, pasta, dog food, ect.) as customer complaints. Let's take a close look at this "quick moving" beetle; the sawtoothed grain beetle (STGB).

Introduction: This beetle is very flat and can shimmy into small cracks and often penetrate improperly sealed packaged foods.

Adult Pupae Larva

It prefers the cracks behind pantry shelves. The small size (1110") in length makes it one of the smallest stored-prod­uct insects.

Saw teeth Even though the 12 saw-teeth on the abdomen of this popular stored-product pest looks obvious, they are not. The insect is only 1110" (2.5 mm) as an adult. You need a lOx microscope or handlens to even see the saw-teeth.

For this reason, it is easier to 'ID ' this live insect by its ability to run- it has ambulatory legs (ie. cockroach) and will

The fastest "bug" on the block

run rather than crawl. If you put a STGB on a piece of paper, it can run to the edge of the paper before you can reach down and pick it up (try it).

Its Problem This mobility allows this pest to run from product to product on grocery shelves. It is a major problem in retail health food stores and grocery stores. The trend in the United States and Canada is going to large (ie. 80,000 sq. ft.) mega stores that stay open seven days a week/ 24 hours per day. Insect complaints have accelerat­ed for many food companies in recent years. Many times it is not the food com­pany's fault- but the lack of good sanita­tion, inspection and rotation by the distri­bution warehouse, trucks, and the stores themselves. Grocery sales is a game of quantity and sanitation is a virtual unknown topic these days.

The STGB thrive in these conditions. One major food company in the Midwest

was sited repeatedly for STGB customer complaints, however, upon close inspec­tion of the manufacturing facility, plant and distribution warehouses, no STGB's could be found - Go figure.

continued on page 2

ARTICLES IN THIS ISSUE

• New Fumigation Technique ... phosphine, carbon dioxide and heat

• Dave's Soapbox

• Better detection of sawtoothed grain beetle

• New products

• Museum section

• DDVP Cancellation

• Quotable Quotes

Fumigauts & Pheromones Page 2

STGB ••• Why do they have saw-teeth? When an insect is in its pupa stage (com­plete metamorphosis: egg, larva, pupa, adult) they are very vulnerable to attack by their enemies (ie. small wasps). The pupa creates these 12 projections (ie. lit­tle volcanos) and secretes a bad tasting substance from the tips. It is their protec­tion as the pupa sits motionless before changing into an adult. This protective organ hardens and becomes vestigial.

Merchant grain beetle ••. A close cousin This insect is often grouped with the STGB. It does have some unique biologi­cal differences. It flies. The eyes are set differently and the thorax is slightly dif­ferent but the real difference is in food preference. The MGB prefers more nuts and nut oils and the STGB prefers more grains, pastas, and dried fruits.

This leads me to believe that many of the STGBs found by the customers in food, nuts, and candies are really MGB that have been misidentified. "Knowing the pest is half the battle in controlling it."

Conclusion Identifying insects can be easier if you know what you are looking for. STGB's are one of the top 5 stored-product insects in the world. The next time a small brown beetle runs to a nearby crack before you can smash it - it is likely the dreaded STGB or MGB ... the fastest' bug's on the block. ~

Dave's Soapbox

I'm SCARED and it's not Halloween!

I just sat through two days at the Methyl

Bromide Controls Workshop/Consulta­tion in Ottawa, Canada. This well attend­ed meeting was co-hosted by Agriculture and Agri-Food Canada and Environmen­tal Canada.

In June of 1992 I was asked to participate in a similar workshop in Washington, DC. This one was requested by the Unit­ed Nations Environment Programme (UNEP) on behalf of the Contracting Par­ties of the Montreal Protocol. What a zoo! Every one had his own agenda. The exporting countries were screaming that there is no ozone problem; the environ­mentalists were praising their position, and the EPA kept saying: "Listen folks it is time to look at the facts, methyl bro­mide is gone, period. Now let's all get on the same page and start looking for alter­natives to this product."

Well, for one-and-a-half years now we all have been denying that there was a prob­lem and questioning the science. And in the background the EPA was been saying "Listen folks it is time ... "

In Ottawa this message was heard stronger than ever when John Reed, of the International Programmes of Environ­ment Canada stated clearly in the opening talk: "Ozone protection is the single most important issue facing mankind today! Never has mankind dealt with a threat like this."

Now that's scary.

The scientists paraded forward for the remainder of the morning to show satel­lite reports, daily UVb readings from the southern hemisphere, comparisons of methyl bromide and its potential effects vs. CFC's and other ozone depleters. One person showed that 25% of the pyto­plankton in the Antarctic region has dis­appeared. The hole in the ozone is now the size of North America over the south­ern tip of this planet.

I'm convinced that this is not some pie in the sky, but a hole in the sky. I don't want to be Chicken Little and run around yelling "The sky is falling, the sky is falling." But... it is time.

Recently I visited Dr. Robert Watson, White House Staff for Science and Tech­nology in Washington D.C. Dr. Watson is formerly from NASA where he won many many awards for his work on atmospheric science. He now consults the Vice-president of the United States. He

mentioned that the ozone hole this year (late October) was deeper but not bigger. Deep is better than bigger.

He stated that if fragments of this ozone hole were to break away and float over highly inhabited areas like New Zealand, Chili, or Australia, disastrous conse­quences could occur.

People, we are not talking about phyto­plankton here or global competitiveness, we are talking about human suffering. For every one percent decrease in the ozone layer, there is a two percent increase in non-melanoma skin cancer. Australia already has lost 5-10% of its ozone layer and one of those breakaway clouds could shoot the UVb (a concern to DNA) level up 20-40%. This does not take in the cases of skin melanoma that are 100% deadly and the increased cataracts caused by the lack of ozone sur­rounding the planet. We are talking potentially I 00,000' s of increased cases of cancer and other human misfortunes.

I'm going public here to announce that my company will phase out the use of methyl bromide, which represents over 50% of our total profits, by the year 1997 or sooner if the science doesn ' t change significantly. I believe methyl bromide is having an impact on the ozone layer. It's important, maybe it is. the single most important issue facing mankind today.

&.k.fu~

Insects Can Be Lured By Scents of Female Sex:

Luring pests to their doom with scents that falsely promise mating, is the sug­gestion put forth in Ger­man entomological circles according to an item in Die Umschau.-Science News Letter: October, 1941.

Page 3 MUSEUM SECTION Fumigants & Pheromones

DDVP Cancellation The final revocation of dichlorvos

(Vapona, DDVP) was signed by the EPA on November 3, 1993. The 409 Tol­erances for dichlorvos have been revoked by this ruling. This means that the prod­uct is not cancelled, but residue in such food must not be in excess of 0.5 parts per million (ppm) on the finished food or packaging materials.

Has the Fat Lady Sung for the Last Time?

The PRESS ADVISORY states: "EPA REVOKES TOLERANCES OF PESTI­CIDE DICHLORVOS IN OR ON PACKAGED OR BAGGED NONPER­ISHABLE PROCESSED FOOD EPA has revoked the food additive tolerance (maximum allowable levels of residues in food) for residues of the pesticide dichloros (2,2-dichlorovinyl dimethyl phosphate (DDVP) in or on packaged or bagged nonperishable processed food. The Agency's action is based on its deter­mination that the food additive tolerance for dichlorovos is inconsistent with the Delaney clause in Section 409 of the Fed­eral Food, Drug and Cosmetic Act (FFDCA). Dichlorvos is classified by EPA as a possible human carcinogen based on laboratory animal tests. The revocation action goes into effect 120 days after publication of this notice in the Federal Register which is expected out on (November 12, 1993)."

"EPA intends to cancel the use of DDVP on packaged or bagged nonperishable processed foods. A special review of dichlorvos is currently underway by EPA

to determine whether other uses of this pesticide should be cancelled or other­wise regulated."

This is the EPA's way of cancelling a use for a product without removing the prod­ucts label. In short, the product can still be used for some label applications as long as it 's not on food products.

This revocation does not include resin strips used in grain bins. This is still con­sidered raw agricultural commodity (wheat, tomatoes, popcorn, etc.) and is covered under the 408 tolerances. This is being considered also by the EPA.

Phase out. There will be a 120 day phase out period for the residues for dichlorvos . This will allow manufacturers time to monitor their existing products for dichlorvos residues and find other uses for existing stocks. This does not mean that there are 120 days to use their left over dichlorvos for treating food prod­ucts.

Risk. If there is product in the commerce system that was treated with dichlorvos prior to this action and it has detectable residues of dichlorvos present, this prod­uct could be confiscated and destroyed. Whether this occurs or not is only specu­lation.

Some people will be sorry to see Vapona go. It was a powerful insect killing tool for many years. The insects were starting to show high levels of resistance. It had an LDso (toxicity rating) of 53 mg/ kg.; it was a strong colinesterase inhibitor; it is a organophosphate with long persistence; it was a mild carcinogen that was used in the food industry; it wasn't a restricted use product. In the future, wide spectrum, non-specific insecticides will continue to be eliminated. ~

INSECT SPOTLIGHT

Clothes Moths ... The Museum Industry's #1 Insect Pest.

I n recent visits to museums throughout the United States and Europe, I have

seen some extreme cases of destruction by these voracious moths. Many pre­served birds and mammals have had to be discarded. Expensive Oriental woolen

rugs have had parts so eaten that the value of repairing the rugs was more than the value of the rug itself. Tapestries that are 100's and even 1000's of years old have severe damage caused by this 'tex­tile beast'. How do you place a dollar value on a 2000 year old tapestry? Let 's learn more about these insects ...

Importance and Type of Injury. There are several species of clothes moths that are responsible for damage, the most common being the casemaking clothes moth (Tinea pellionella) and the webbing clothes moth (Tineola bisselliella). Fab­rics injured by clothes moths have holes eaten through them by small, white lar­vae, and in most cases the presence of the insect is indicated by silken cases or lines of silken threads over the surface of the materials. Materials left undisturbed for some time or stored in dark places are most severely injured by these insects. Small, buff-colored moths, not over 112 inch across the wings, will be found run­ning over the surface of infested goods when such goods are exposed to light, or flying somewhat aimlessly about the houses or closets. The clothes moths are not attracted to lights .

EGG 0 lt.IOrlr. ...... l~-

Food. Clothes moth larvae feed on wool , hair, feathers, furs , upholstered furniture, occasionally on dead insects, dry dead animals, animal and fish meals, milk powders such as casein, and nearly all animal products, such as bristles, dried hair and leather. This is much of what som'e museums might have stored and displayed.

Distribution. Clothes moths are distrib­uted generally over the world.

Fumigants & Pheromones Page 4

Life History, Appearance, and Habits. The adult "millers" or moths are entirely harmless and probably take no food of any sort. They lay their eggs singly on the products in which the larvae feed, each female laying 100 to 150 eggs (1/50 inch long).

Their white color and the frass from the larvae makes them rather conspicuous when tapped onto a black piece of paper. The larvae which hatch from these eggs are the only stage of the insect causing damage. They are white, and vary in size from about l/16 inch long, when first hatched, up to about l/3 inch when full­grown. The length of the larval period varies greatly according to the conditions and food supply. The complete develop­ment of this stage may take from 6 weeks to nearly 4 years. Development is greatly influenced by humidity, the life cycle being shortest, in average room tempera­ture, at about 75 per cent relative humidi­ty. In heated buildings (ie. oriental carpet stores), the adults may be found at any time of the year but are most abundant during the summer months.

Pheromones. The pheromone for the webbing clothes moth has been identified and synthetically produced in 1993. Insects Limited, Inc. is proud to announce that this pheromone will be exclusively available in early 1994. The pheromone is quite active for the adults. The pheromone is a two component two dou­ble bond aldehyde (difficult to synthe­size). If you are interested in obtaining this pheromone, contact Insects Limited, Inc.

Control. Frequent dusting, brushing, vacuum cleaning, and steam cleaning are very important non-toxic control mea­sures and should be extended to the most remote cracks, warm and cold air pas­sages, and similar hiding places. Layers of cotton will not be damaged by clothes moths. Vault fumigations can be effec­tive. Methyl bromide should not be used for these fumigations however, magne­sium phosphide, argon, carbon dioxide, nitrogen, oxygen-free environments, and/or combinations of these techniques can be utilized. Clothing which is in daily use is practically never infested by the clothes moths. It is important that cloth­ing, other fabrics, or woolen rugs placed in storage, should be free of moths and a detection program with pheromone traps implemented.

source: Destructive and Useful Insects, Metcalf, Flint, and Metcalf.

Setter Detection of Sawtooth Grain Beetles

By, Paul Cogan, Central Science Labora­tory (CSL), MAFF, Slough, England; Paul was a moderator and speaker at this year's International Technical Confer­ence in Lubeck, Germany.

As Wendell Burkholder noted in issue 31 of this newsletter, traps will indi­

cate the location of beetles and are effec­tive in giving warning of infestations. But how effective are they? We compared the ability of traps to detect beetles with detection by sampling procedures and found that traps were at least lO times more effective than sampling. We have conducted trials releasing 450 sawtooth (Oryzaephilus surinamensis) into 150 kg of grain in bins held at 25°C. Average unbaited trap capture over a 3 day period was at best only 5% of the released bee­tles. In a recent experiment at CSL only l% of sawtooth were trapped over a peri­od of several months from 120,000 released into bins totaling 120 tons of wheat. Traps are good, but indications are that only a small percentage of beetles are captured using unbaited traps. For a storekeeper to have faith in traps, espe­cially that a nil capture means no infesta­tion, there is a need to increase the ability of traps to capture this and other beetle pests. At CSL we have looked at improv­ing detection of all beetle pests by the food volitiles and pheromones and are currently developing a food lure which will attract not only sawtooth but all stor­age beetle pests.

We have also studied the aggregation

pheromone produced by male sawtooth which attracts both sexes. The 3 lactones comprising the sawtooth pheromone have been known for some time but synthetic production of them has been expensive. We have now reduced the costs to an economically viable level and produced lactones with a purity of >96%. We have established the optimal blend of the lac­tones to which we have added an inex­pensive synergist. The synergist decreas­es costs whilst increasing the capture of the sawtooth in lab bench tests by 50%.

Testing our lure in laboratory bin tests, we tested the lure against populations other than our standard lab cultures. We tested the lure against various sawtooth populations including some organophos­phate-resistant ones which had different behavioral patterns from our lab cultures and the lure proved effective against them all.

We are now in the final stages of devel­opment of this lure. Providing the lure does not decrease capture of other storage beetles, then CSL will be ready to release on the unsuspecting sawtooth another weapon in the detection armory. ~

INSECT 810-ASSAYS for fumigations

I nsects Limited, Inc. has a new tool available for the skilled fumigator.

Insect Bio-Assays are live insects that are placed in a small vial. They then are placed throughout the fumigated area prior to the release of the fumigant. After the fumigation, they are gathered to be checked and incubated for a period of time.

Page 5 Fumigants & Pheromones

All Stages & Multiple Species Available The adult stage of a beetle is relatively easy to kill with fumigants. The difficult stages to kill are the immobile stages (ie. eggs, pupa). Insects Limited, Inc. has all four stages available for Insect Bio­Assay. Here are the various species that are available: Rice Weevil (Sitophilus oryzae), Red flour beetle (Tribolium cas­taneum), Indian meal moth ( Plodia inter­punctella), Warehouse beetle (Trogoder­ma variable), Mediterranean flour moth (Ephestia kuehniella), Webbing clothes moth (Tineola bisselliella) . There will be more species available.

Extreme Temperature for Insects The response of stored-product insects to temperature*

Zone Temp.('C) Effect

Lethal 5D-60 death in minutes

45 death in hours

Suboptimum 35 development stops

Optimum 25-33 maximum rate of development

Suboptimum 13-25 development slows

13-20 development stops

Lethal 5 death in days {unacclimated), movement stops

·1D-5 death in weeks to months {acclimated)

-18 most stored-product insects die

-25- -15 death in minutes, insects freeze

*Species, stage of development and moisture content of food will influ-ence the response to temperature.

source: Paul G. Fields, Ph.D. The Control of Stored-Product Insects and Mites with Extreme Temperatures, J. stored Prod. Res., 1992.

Cost The Insect Bio-Assays from Insects Lim­ited, Inc. will come 15 vials in a packet. Each vial will have 10 or more insects in a food media. Each packet will be $54.75 . Each packet will be shipped next day air within the United States only. Shipping charges will be added to the invoice.

Efficiency

Now more than ever it is extremely important to be sure that your fumigation was a success. Gas readings are impor­tant. Adult insect bio-assays are good, but the ability to place eggs, larvae, pupae, and adults of multiple species in a fumi­gated structure will give you and your customer the added confidence to walk away with a better picture of the outcome of a skilled fumigation .

Pest Monitoring Software Offers New Version 2.1

PEST MONITORING sonwARE

I nsects Limited, Inc. is proud to

announce the latest version of its Pest Monitoring Soft­ware. It has been a year since the origi­nal version was

released and we feel that we've made quite a few improvements since that time. The original version offered a means of keeping detailed records of insect and rodent trapping programs as well as offering reports and graphs of these loca­tions. Version 2.1 offers all of this plus a whole lot more.

Here are just some • ofthenew features: • A mapping feature which gives a unique · visual layout of each facility along with trap location and trap catches

• An on-screen timer which alerts you when you need to change traps, lures or bait

• An On-Line Instant Help Box which

gives a quick explanation of each menu selection

• Numerous menu improvements which allow quick and easy movement throughout the program

• Customized Printer selection

• A menu option which allows entering trap catches for only a few traps and will automatically assign a zero trap catch for all the remaining traps (A big time saver for large accounts)

• Combine sites for reports and graphs (For extra-large accounts)

• And many More!

We at Insects Limited have made many of these changes based on the feedback from our customers. We feel that they are a valuable addition to the original pro­gram and we highly recommend it to either the first time buyer or as an update for current owners. Pest Monitoring Soft­ware will run on IBM Compatible com­puters only and is available in whatever disk size you would like.

The cost is $175.00 plus shipping (For 1st time purchasers) or $75.00 for an update (If you had already purchased ver­sion 2.0)

AEPA Regulatory Action Under the Clean Air Act on Methyl Bromide On November 30, 1993 the Environ­

mental Protection Agency (EPA) added methyl bromide to the Clean Air Act list of class I Ozone Depleting Sub­stances (OPS). The EPA final rule will freeze U.S. production and importation of methyl bromide in 1994 at 1991 levels, with a phase out of production and importation by the year 2001.

0 The Clean Air Act requires that all substances with an Ozone Depletion

continued on page 7

Fumigants & Pheromones Page 6

Practical Use of Fumigants & Pheromones Technical Conference & Workshop. December 1-3, 1993. Lubeck, Germany.

N. S. & P. S. Pruthi; Pest Control, Mwalshe, India

Moshe Calderon, Ph.D.; The 'Storyteller '.

Methyl Bromide Panel; B. Taylor,

C. Smith, C. Reichmuth,

L. Kline

A f estive banquet aboard the 'Passat ' in the Baltic Sea.

Lee Ryan, Ph.D.; Philip Morris Europe,

Switzerland

Moderator, Speaker, Referee, Song master ... Jerry Sullivan, Ph.D

Dr. Wendell Burkholder; 30 years of Patient Research on Insect Behavior

Photos by Stan Brookie

Dr. Lather Benzing, Detia

'The Trainer '

Dr. Pasquale Trematerra;

Mating disruption in flour mills

wlth pheromones in Italy.

Stanislaw lgnatowicz, Ph.D.; Agricultural Uni versity of Warsaw, Poland

Page 7 Fumigants & Pheromones

Potential (ODP) of 0.2 or greater be listed as class I substances, and be phased out within 7 years of listing. Based upon the latest international scientific assessment, the ODP for methyl bromide is 0.7. Sci­entists believe that bromide from methyl bromide is far more effective at ozone depletion than chlorine from CFCs. 0 This rule is more stringent than the Montreal Protocol freeze on production in 1995 at 199llevels. 0 The scientific basis for these actions is supported by the National Aeronautics and Space Administration, the National Oceanic and Atmospheric Administra­tion, and represents a consensus of atmospheric scientists (Montreal Proto­col). 0 Methyl bromide is a pesticide utilized for soil fumigation (80% of its world­use), and structural fumigation (5% of use). 0 EPA recognizes that methyl bromide is important, and will strive to protect the environment as required under the Clean Air Act in ways that minimize the effect on agriculture. Although there is no sin­gle alternative chemical treatment which can duplicate the action of methyl bro­mide, alternative chemicals and growing methods can substitute in many situa­tions. More Information: stratospheric Ozone Hotline at 1-800-296-1996, or Bill Thomas, EPA/OAP/SPD (6205J), 401 M Street S.W., Washington, D.C. 20460, tel: (202) 233-9179 FAX: (202) 233-9577. '*

Seminar Shares with 27 Countries Practical Use of Fumigants & Phero­

mones Technical Conference and Workshop was held December 1-3 in Lubeck, Germany. Participants from 27 countries were represented from the pest

control, fumigation , processed food , tobacco, grain/milling, university and gov­ernmental agencies . Over 120 came to this historic North­em Germany city located between

Hamburg and the Baltic Sea. They came to listen, discuss, share view-points and ideas from: Argentina, Australia, Bel-

gium, Brazil, Brunei Darussalam, Cana­da, Czech Republic, Denmark, England, Hungary, India, Northern Ireland, Israel, Finland, Germany, Greece, Italy, Kuwait, Lebanon, The Netherlands, Poland, Por­tugal, Sweden, Switzerland, Taiwan, United States and Zimbabwe.

Lee Ryan, Ph.D., of Phillip Morris Europe stated: "I was surprised when I came from the States several years ago to Europe that there were no real training programs for the stored-product protec­tion and fumigation community. I believe this in the future ."

Jerry Sullivan, Ph.D., summarized the conference by saying in his closing remarks: "This conference covered some important aspects of fumigation and the use of pheromones. The Panel on Methyl Bromide clearly showed that this chemi­cal will be lost as a fumigant and I think we all are aware that politics are highly involved in the decision to ban its use."

"Several papers were presented on inert atmospheres or modified atmospheres which clearly showed the effectiveness of these methods. Previous disadvantages of these chemicals such as time of fumiga­tion may have been solved with the report of Dave Mueller where he found in his trials, successful fumigations with carbon dioxide+ phosphine+moderate heat in 24 hours . We heard interesting reports on other methods such as irradiation, genetic control, physical control, physiological control, biological control and chilling. The need for further work in the field of fumigation was clearly pointed out."

"We also heard interesting reports on the monitoring of phosphine by fixed or · portable instruments and a spirited dis­cussion following an excellent report on phosphine resistance from Larry Zettler, Ph.D. Resistance management must be given more consideration in the future. Two proposals were suggested from this discussion to slow the tide of phosphine resistance: mandatory pressure testing prior to releasing the fumigant, and using test insect cages with all stages of test insects to determine the effectiveness of the fumigation ."

"We were also privileged to hear very interesting reports on pheromones, their chemical structures, their use and how they could be employed. It was very interesting to hear the report of Dr. Burk­holder on 30 years of research with

pheromones. This clearly showed how this field has advanced during this time period. Dr. Burkholder stated in his clos­ing remarks: 'This is what we have done, now it is time for the next generation to carry on.' At the conclusion of the meet­ing David Mueller presented Dr. Burk­holder a check from the proceeds of this conference to create a scholarship for stu­dent support in the stored products area. The scholarship will be named in honor of Wendell Burkholder, Ph.D. and pre­sented annually."

"Jeffery Brown, Ph.D., gave all of us a reason to consider who we are and what we are - eagles, otters, or unicorns. Toxi­copy, as discussed by Dr. Ulrich Schwarz, alerted us to this serious prob­lem and how we can possibly solve such a problem. Lee Ryan , Ph.D., presented a very good approach to a proper sanita­tion/hygiene program. Paul Cogan did an excellent job of highlighting the museum pest management topic and his work on the sawtoothed grain beetle pheromone."

It was stated in a recent N.P.C.A. keynote lecture that there are three things that will help our industries survive and prosper in the current business climate: education, education, and education. The Lubeck Meeting was an example of such an edu­cational experience where international sharing can make us all more knowledge­able and better at our job of protecting property and food . The next Fumigants & Pheromones Technical Conference and Workshop will be December 6-8, 1994 in Indianapolis. ~

New Product Announcement

Webbing clothes moth pheromone is available from Insects Limited, Inc. Pheromone Kit: 1 0 traps and 1 0 lures: $74.00/kit 10 kits/case: $666.00/case

Fumigants & Pheromones Page 8

'' QUOTABLE QUOTES

'' "We don't inherit the world from our ancestors, we borrow it from our chil­dren." Chief Joseph/Jonathan Banks, Ottawa 11/93.

"Survival of your business doesn't depend on methyl bromide, it depends on the public." Dr. Stephen Andersen, EPA, Ottawa 11/93.

"When you have a global issue, you have a global market." Stephen Andersen, Ph.D., EPA, Ottawa, 11193.

"There is a zero percent chance of the Clean Air Act being amended for methyl bromide exemption." Andersen

"Someday science and reason will over­come emotion and fear." Jerry Heaps, BCE, Minneapolis, MN.

"In 1987, 27 contracting countries signed the Montreal Protocol. In 1993 over 120 countries have signed the document." John Reed, Environment Canada, Ottawa, 11/93.

"You can't solve the problem thinking the same way you were thinking when you got into the problem." A. Einstein

Quotable Quotes from National Pest Control Association (NPCAJ in Washington, DC: Jack Kemp, undeclared 1996 Presidential

Fumigation Service & Supply, Inc. 10540 Jessup Blvd. Indianapolis, IN 46280-1451 317-846-5444 FAX 317-846-9799

Candidate said: "It is confidence that makes a business work."

"Since 1968 we have spent $5 trillion fighting poverty in this country and poverty is winning."

"Capitalism without capital is just an ism." Jesse Jackson/Jack Kemp

"Washington is Phaeroh, I will shout to Congress today on the Hill: 'Let my peo­ple go!'

Dr. Lynn R. Goldman, United States Environmental Protection Agency, Assistant Administrator

"EPA's future pesticide policy changes for FIFRA will be:

"Every 15 years a product will need to be reregistered."

"There will be a quicker removal of pesti­cides, it now takes about five years."

"Enforcement procedures will be enhanced."

"The current trend to reform pesticides is greater than ever before."

"The major focus are children - their pro­tection is the aim of this administration."

Question to Dr. Goldman (medical doc­tor): "What is the current status of methyl bromide by the EPA?"

Reply: "We will work with you to find alternatives to this product."

:: )

Attention Mailroom Personnel (or Addressee)- Please Reroute if Necessary

Fumigants & Pheromones Technical Conference and Workshop December 6-8, 1994

University Place Hotel & Confer­ence Center, Indianapolis/USA

Fumigants & Pheromones is published by Fumigation Service & Supply, Inc. and Insects Limited, Inc .for the professional applicator. We hope that the information that you receive from this newsletter will help you in your business, and you. in turn, will support our business efforts. If you have an associate who would be interested in receiving this newsletter, please contact the address below. We would welcome any comments or suggestions for topics. Address correspondence to: David K. Mueller, Fumigation Service & Supply, Inc., P.O. Box 40641, Indianapolis, IN 46280.

~~~~~ ~~~~ Insects Limited

Copyright 1994 Fumigation Service & Supply, Inc. All rights reserved. No part of this publication may be reproduced or transmitted by any means without permission of the editor.

U.S. Postage PAID

Carmel, IN Bulk Permit #14

A New Method of Using Low Levels of Phosphine in Combination with Heat and Carbon Dioxide.

By David K. Mueller Fumigation Service & Supply, Inc.

Indianapolis, Indiana USA 46280-1451

Patent Pending

ABSTRACT - A combination of low levels of phosphine (65 -100 ppm), heat (32- 37 degrees (C), and carbon dioxide (4%- 6%) were used in three mills in the United States. Fumigations were car­ried out for 24 hours. Multiple species of stored-product insects in various life stages were used as bio-assays. A corrosion study was conducted with copper and electronic equipment. A penetration study was conducted with 2 and 3 meter deep tubes filled with wheat flour. All insect bio-assays were retained for 30 days. A 100% insect mortality within bio-assays was achieved in 24 hours or less. This method of fumigation holds promise as a replacement for methyl bromide fumigations in flour mills and similar structures.

KEY WORDS: Magnesium phosphide, carbon dioxide, penetration, corrosion, Tribolium castaneum

Purpose: To evaluate the use of combination treatments to effectively control given populations of stored-product insects. Insects are stressed by the increased levels of carbon dioxide and heat. This allows lower levels of phosphine to be more effective in shorter periods of time.

History

Fumigations with inert gases and methyl bromide have been performed since 1929. The famous stored-product ento­mologist R.T. Cotton is noted for the work and patented a combination method. More recently, the Australians have performed numerous experiments with carbon dioxide and phosphine on commodities in sealed structures. The Israelis patented a method in 1979 for using four parts carbon dioxide with one part methyl bromide in grain storages. Carmi and Leesch have shown that carbon dioxide is effective in moving an atmosphere of phosphine deeper into the grain mass.

Mueller states in The Mallis Handbook of Pest Control 7th ed. that there are several ways to produce insect stress includ­ing: l) decreasing oxygen concentration, 2) increasing carbon dioxide levels, or 3) increasing temperature. It has been pub­lished that insect respiration can be increased by 50% by increasing carbon dioxide levels to 3%. Insect respiration increased 300% when carbon dioxide levels were raised to 5%.

Materials and Methods

Fumigants. Fumigants for this study were produced from Degesch FUMI-CEL™ and Degesch FUMI-STRIP™, a mag­nesium phosphide formulation in a solid plate form. Each plate generates 33 grams of hydrogen phosphide (phosphine) gas. These formulations have advantages over standard alu­minum phosphide formulations in that gas is generated more rapidly. A minimum concentration of 100 ppm can be achieved in seven hours at 32 degrees (C) and 50% RH. This compares to eleven hours with aluminum phosphide at the

same tested dosage rates and conditions. Dosage. A dosage rate of 6.6 grams per 1000 cu.ft. was

initially used to treat each location. One gram of phosphine produces 25 ppm in 1000 cu. ft. The theoretical maximum concentration for the dosage rate was 165 ppm. Conventional fumigations with phosphine would have concentrations between 850 and 1500 ppm. Each of the three locations showed peak phosphine concentrations of more than 50% of the theoretical maximum concentration. These concentrations were representative of properly sealed buildings.

11100

ALTERNATIVE PHOSPHINE FUMIGATION GAS CONCENTRATION

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TIME (HOURS)

The first location (Mill #1) was a two story, 60,000 cu.ft. feed mill at Purdue University in West Lafayette, IN. The sec­ond location (Mill #2) was a six story, 181,000 cu . ft. flour mill in Honolulu, HI. The third location (Mill #3) was a six story, 300,000 cu.ft. flour mill in Frankenmuth, MI. All fumi­gations were carried out during the summer of 1993.

Carbon Dioxide. During the first combination fumigation at Purdue University (Mill #1), a total of 37 fifty pound steel cylinders of carbon dioxide were used during the fumigation. Use of cylinders was cumbersome and more expensive than larger vessels.

Carbon dioxide must be vaporized from a liquid to a gaseous state. Gas temperatures should range from 70 - 90 degrees (F) or 20 - 30 degrees (C) when entering the building. Special hoses and regulators are required when working with -40 degree (F) liquid carbon dioxide. Advanced knowledge of how to control and release this inert gas is necessary. Even though carbon dioxide is inert, it can be very deadly. Oxygen levels are decreased when carbon dioxide enters a building. Carbon dioxide should be treated as a hazardous fumigant similar to methyl bromide and phosphine.

20

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ALTERNATIVE PHOSPHI E FUMIGATION CARBON DIOXIDE CONCENTRATION

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1 2 3 • 5 6 7 8 9 10 11 12 13 14 16 17 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 46

TIME (HOURS)

Heat. Frequently mills and similar facilities have heating systems that maintain a content temperature in the building. The Purdue University location utilized electric heaters to maintain a 100 degree (F) 38 degree (C) temperature ( + or -) 2 degrees (C). The Hawaiian Flour Mill (Mill #2) had no heat­ing system. No heaters were available on the island of Oahu.

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ALTERNATIVE PHOSPHINE FUMIGATION TEMPERATURE

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The ambient temperature of the flour mill was 30 - 31 (C) temperatures necessary for the combination techniques. A steam boiler was used to heat radiators in the building and an additional steam coil-type 125,000 BTU heater was utilized to enhance heating capacity. Outdoor temperatures during the Michigan fumigation (Mill #3) reached 4 degrees (C) or 40 degrees (F). The other two fumigations (Mill #1 and Mill #2) were performed on warm summer days.

Results Test Insects. Mill #1 - Test insects were placed in four locations at the

Purdue Feed Mill. Four species of insects were utilized. These included: Angoumois grain moth (Sitotroga cerealella), Red flour beetles (Tribolium castaneum), Warehouse beetles (Trogoderma variable), and Rice weevils (Sitophilus oryzae). Eggs, larvae, pupae, and adults were placed in 250 ml plastic containers.

Two groups of 36 containers were placed on the first floor

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and two groups of 36 containers were placed on the second floor.

Test insects were retrieved from the fumigated mill begin­ning 20 hours after the start of fumigation. Test insects con­tinued to be retrieved every four hours until 48 hours after the start of fumigation. Adult and larval stages were evaluated for all sampling intervals. All insect stages were dead starting 20 hours into the fumigation. All of the containers were taken to the lab at Purdue University and incubated for 30 days in a growth chamber. No insect activity was observed after 30 days . Control insects remained alive throughout the evalua­tion period.

Test insect bio-assays were used at the Purdue Feed Mill. Four sets of these bio-assays were placed throughtout the mill. They were incubated for 30 days after the fumigation to check for egg survivors. None apppeared after 30 days.

Mill #2 - Two species of stored-product insects were placed as bio-assays in the flour mill fumigation in Hawaii; Red flour beetles (Tribolium castanium) eggs, larvae, pupae, and adults (Indiana strain and Hawaii strain), and Rice weevil (Sitophilus oryzae) adults. A total of 150 insect cages with ten or more insects per cage were placed on the six floors. Insect cages were placed approximately one meter above the floor. Insect cages were retrieved from the building beginning 13 hours after . the start of fumigation. All insects within bio­assays and retrieved at the 13 hour interval were dead. All insects retrieved from the flour mill at 24 hours after the start of fumigation were also dead. These insects were incubated in Hawaii and Indianapolis for 30 days with no activity observed. All indoor and outdoor insect control groups were alive 48 hours after the fumigation start and 87% were alive after 30 days.

Mill #3 - During the Michigan flour mill fumigation three species of stored-product insects were used in bio-assays. Red flour beetle eggs, larvae, pupae, and adults, Rice weevil adults, and lndianmeal moth eggs ( Plodia interpunctella).

Insect cages were placed on each floor and controls were maintained as described previously. Over 150 cages were placed in the mill with I 0 or more insects per cage.

Insect cages were retrieved from the building twelve hours after the start of the fumigation. All adult and larval speci­mens were dead twelve hours from the beginning of the fumi-

gation. All insects retrieved from twelve to 24 hours after the start of fumigation were subsequently dead. All specimens were held at room temperature. No insect activity was observed for any stage of the three stored-product insects test­ed. Controls from outdoor cages and indoor cages remained alive.

Penetration Study Phosphine and carbon dioxide are excellent penetrating

gases. Phosphine is a more effective penetrator than methyl bro­

rrude. Twelve six inch diameter X 6 ft. long PVC pipes were capped and permanently sealed on one end. Insect cages were placed in the bottom of these long tubes. Each tube was sub­sequently filled to a three-foot level with wheat flour and insect cages were placed at that level. Flour was again added to the remaining three feet and tubes were filled completely. A 1.4 mil polyethylene bag was secured with tape over the open end of each tube. Two tubes were placed on each of six floors of the (Mill #2) Hawaiian Flour Mill (HFM).

Penetration study in Michigan flour mill

Five flour-filled tubes were retrieved from the flour rrull 24 hours after the start of the fumigation. Carbon dioxide and phosphine levels were measured with a Draeger tube and lev­els were found to be equal to the ambient concentration of the fumigated rrull. Phosphine levels under polyethylene bags were 50 ppm the carbon dioxide levels were 3%. Test insects at 3 feet and 6 feet were evaluated. All adults and larvae were dead. Eggs and pupae were incubated for 30 days.

The remaining six tubes were retrieved 48 hours after the start of fumigation . To affect a kill on test insects, gases had to penetrate the 1.4 mil polyethylene bag, permeate 3 to 6 feet of flour and inside polyethylene bio-assay tubes and kill eggs, larvae, pupae, and adult insect specimens. Insects in control groups remained alive. After 30 days, insects in polyethylene vials positioned at the bottom of 6 foot flour tubes showed some survival in the first instar larvae stage. Some eggs had survived this penetration study.

The study was taken one step further in Michigan (Mill #3). Two 5-foot and one 10-foot tube similar to those described above were placed in the furrugated rrull. All stages of insects were positioned at 10 foot, 5 foot, and I foot lev­els within tubes. A 1.4 mil polyethylene bag was placed over one five foot tube. No bags were placed over the remaining tubes.

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Observations twelve hours after the start of fumigation indicated that insects at the bottom of the five foot tube with­out a plastic bag were dead. After 24 hours the test insects at the bottom of the 5 foot tube with bag and ten feet tube were dead. The immature stages were incubated for 30 days. No survivors appeared after 30 days. This furrugation was about 4 degrees (C) or 10 degrees (F) warmer than the Hawaiian study. The gas concentrations were nearly the same.

Corrosion Study One negative characteristic of phosphine is that under cer­

tain conditions it can cause corrosion of precious metals and coppers. Many items should be removed from buildings to be fumigated when possible. Often it is impossible to remove items that could be affected by high levels of phosphine and high humidity.

Phosphine produced from magnesium phosphide or alu­minum phosphide can generate phosphoric acid. When phos­phoric acid and sufficient moisture are combined on precious metals, a rruld acid is formed and corrosion occurs. With severe corrosion, instruments will often fail. Corrosion man­agement is necessary when phosphine is to be used in fumi­gating buildings that contain printed circuits, and sensitive equipment.

Heat and carbon dioxide will lower hurrudity within a facility. Samples of wheat from the Michigan location (Mill #3) dropped from 13 to 11 percent moisture during the fumi­gation process, while moisture in the flour mill dropped 12% (56% vs. 44% ).

ALTERNATIVE PHOSPHINE FUMIGATION OXYGEN CONCENTRATION

1 2 3 .c s s 1 a s 10 11 12 13 1o11 16 11 1a 20 22 24 26 u 30 32 34 36 38 40 42 4.41 415 .u TIME (HOURS)

By managing large peaks in phosphine gas levels, levels of HJPO. can also be managed. Phosphine levels should remain in a range from 50 to I 00 ppm with the need for magnesium phosphide furrugant to be physically removed when levels reach 150 ppm. Magnesium phosphide can be easily added or removed from buildings to achieve these target levels. Proper safety precautions are necessary.

A new method of evaluating corrosion was developed for this test. New copper pennies where placed throughout the structures to determine severity of corrosion with combina­tion fumigation techniques. Each penny was labeled with a number and weighed prior to fumigation. Pennies were locat­ed randomly throughout each structure and placed vertically

on-edge. Some pennies were suspended from ceilings with fishing line at various heights. Solid blocks of steel and copper where placed within the Purdue Feed Mill during fumigation.

Results of the corrosion study revealed small weight gains of each of the pennies. Average weight gains of .0009 grams for the 10 pennies in the Michigan study and average weight gains of .0040 grams were observed for 31 pennies in the Hawaiian study.

Electron microscope scans revealed no traces of phospho­rus or other elements (except inherent impurities) on the two steel samples placed on the first and second floors of the feed mill. No traces were found in the copper sample (apart from impurities) placed on the second floor of the mill. The copper sample placed on the first floor, did show a treatment effect of about 8% phosphorus contamination (average of two read­ings) due to phosphine gas treatment.

Although this information is preliminary, future compar­isons should allow for ratings of corrosion potential and a determination of the method's viability.

A ten-penny corrosion test is planned for each future fumi­gation. Average percent weight gains should be a factor that will help with corrosion management assessment programs.

Cost Real costs of a fumigation are related to shutdown time.

Many mills and processed food operations cannot afford shut­downs longer than 24 hours.

The costs of carbon dioxide are offset by reduced costs for magnesium phosphide. Additional costs for equipment rental (vaporizer and vessel) also exist. Permanent installation of such equipment would be relatively simple. Additional costs for heat would be determined by outdoor temperatures and how well a building is sealed and/or insulated. Additional steam coils or electrical heaters could be installed if necessary.

It is difficult to determine the specifics of a building with­out studying it extensively during the first few combination fumigations. This will require many around-the-clock gas readings throughout the building. After experience is gained in stabilizing and maintaining levels of phosphine within the proper range, combination fumigations can be very success­ful and cost-effective.

Conclusion The future of the fumigation business is unclear. Dozens of

fumigants have been removed from the market during the past

4

decade. Methyl bromide has been identified as a serious ozone depletor with an Ozone Depletion Potentional (ODP) of 0.7. The Clean Air Act in the United States declares that any product with an ODP of 0.2 or greater will be eliminated in due course. The Montreal Protocol's 120 plus signitore countries are discussing similar retribution. There may be a day in the near future when phosphine could be the only con­ventional fumigant available.

With this uncertainty, alternatives are needed to eliminate insects from structures. Methyl bromide provides several advantages in that it acts quickly (24 hours or less), is inex­pensive, and causes minimum damage to contents of struc­tures, although it is a less aggressive penetrator than phos­phine, it provides for effective kill of pests.

A Combination Method of fumigation using maintained lower levels of phosphine, moderate heat, and higher carbon dioxide levels for a 24 hour periods in sealed structures has potential for replacing many methyl bromide applications within mills and similar structures.

Acknowledgement I thank John Mueller (Fumigation Service & Supply, Inc.,

Indianapolis, IN) for his fumigation expertise, and Larry Pierce (Food Protection Services, Mililani, Hawaii) for his assistance, and to Dirk Maier, Ph.D. (Purdue University, Agricultural Engineering Department) for his assistance on the corrosion study, and Prof. Hruska (Purdue University, Metallurgical Engineering Department for his analysis of the copper and steel specimens, and to Linda Mason, Ph.D. (Purdue Entomology Department) for her assistance with the stored-product insect bio-assays and their evaluation, and Degesch America, Inc. for contributing the magnesium phos­phide, and Fred Whitford, Ph.D. (Purdue Training and Certification Division) for his assistance and photography, and Angie Richards (Insects Limited, Inc., Indianapolis, IN) for the graphs and data collecting, and HFM Foods, Inc. (Hawaiian Flour Mills) for performing this test on their facil­ity, especially Don Sorum, their Cereal Chemist, and Dick Kraft of Star of the West Milling for his strong support and belief in Al's sons, and to Keith Weber for getting the build­ing sealed and the work done right and to Mike Culy, Ph.D. and Curt Hale for their detailed review.