

DRAFT Stored Food Pests FAQ

Copyright Eric Richard Paulsen, 1997
This being a draft version may not be archived, or used as reference
until it is formally released after the newgroup has had an opportunity
to give me feedback on this draft.

DISCLAIMER:  This FAQ is does not include all pests, nor is it intended
to be an end resource for the identification and control of such pests.

My primary resource used for writing this FAQ was "General Pest Field
Representative Exam Study Guide" by Munro & Paulsen, Copyright 1995 -
Pest Control Operators of California Inc.

Pesticide Disclaimer: The mention of any pesticides should not be
construed to be a recommendation or endorsement of such products.  Use
only Registered Pesticide Products and Read and follow all Label
Directions.  The Label is the Law.  Although there are some good
homemade pesticides, most I have seen recommend unsafe use of such
products or are such products, which are ineffective.

1: The Key to Controlling Pests; proper identification.  To control any
pest, one needs to first make a proper identification of the pest, and
secondly know the pest's biology so a proper management strategy may be
planned.  Pesticides should only be used as part of a larger all
inclusive Integrated Pest Management Plan.  So how can you really
identify these pests based on your descriptions?   Van Waters & Rogers
has the largest collection of insect (and other pests) specimen slides
in the world.  Go to their specimen slide search engine page
http://www.pestweb.com/pps/slidea.htm and type in the name of the pest
from this FAQ you wish to see.  The images on the web have large
transparent VW&R written across them (which is absent on their real
"slides" which may be purchased) but their web images are still
excellent!

2: What is the importance of Stored Food Pests?

Between harvest and reaching your dinner table better than 20% of food
harvested in the US is destroyed by pests.  In third world countries
this number is often as high as 80% or greater.  The sad fact is that
much of the food we send to third world countries in the form of
charities simply eaten by insects and rodents on the docks of foreign
shores.

Pests in your stored food can be at a minimum a frustrating
inconvenience, in a worse case they may cause illness and or destroy
your entire food storage cache.

Post Harvest Bulk Grain Stored Product Pest Control during transport,
storage, and processing consists of the following:

a) Monitoring for pests
b) Control using fumigants (methyl bromide, phosphine and others)
c) Control using insect growth regulators and other pesticides
d) Adding diatomaceous earth to grain
e) Pheromone Traps
f) Modified Environments
g) Parasitic wasps

3: THE USDA INSPECTS FOODS DISTRIBUTED IN RETAIL TRADE
The USDA is responsible for inspecting for insect infestations as well
as other contaminants.  Random samples are tested for insect and rodent
parts, and feces, as well as fungal infestations.  The number of these
fragments determines whether the product may be sold to consumers, or
must be sold as feed stock or if it must be destroyed rather than to be
consumed by either man or animal.

4: CONSUMER STORED PRODUCT PESTS

This FAQ will cover several major groups of Stored Product Pests; Insect
pests, being beetles, weevils, and moths,  Rodents, and Fungi.

A) Insects
B) Rodents
C) Fungi & Mites


A) INSECTS:
The  insect pests of our stored food products consist of many different
species, but are primarily either of the  order  Coleoptera (beetles and
weevils) and Lepidoptera (moths).  In this section we will review  some
of  the more common species of both order.

The  different  species are divided into three groups according to their
feeding habits.   There  are  internal feeders, external feeders, and
scavengers.


*INTERNAL FEEDERS
The  internal  feeders  are so  called  because  the  female deposits
a  single  egg  inside a whole kernel  of  grain.   The  egg hatching,
the larvae feeding, and the pupation all occur within that grain
kernel.  These insects are primarily a problem in fields or  in grain
storage and processing facilities.

RICE WEEVIL & GRANARY WEEVIL
1. adult is reddish-brown in color; about 1/8" long
2. Rice weevil has four light colored spots on the wing covers and the
wing cover is dotted with small round punctures.
3. the rice weevil is one of the most destructive insect pests of stored
grain in the United States
4. weevils can be identified by the presence of the characteristic
"snout" that is used for boring into the grain kernels
5. Granary weevil back covers have elongated oval punctures and no
colorations; it has no wings
6. Granary weevil cannot fly so infestation is restricted to stored
whole grains; rice weevil is a good flier so also infests fields
7. under ideal conditions, development from egg to adult takes as little
as four weeks
8. the adult female lives four to eight months during which time it lays
up to 400 eggs
9. both can survive the winter by hibernating
10. the adults are sometimes found in flour or macaroni,  but their eggs
cannot hatch in these materials

BEAN WEEVIL
1. This insect, actually a beetle, is called a weevil because its
feeding and egg laying habits are like the weevil
2. the adults and larvae feed on beans

ANGOUMOIS GRAIN MOTH
1. this pest is frequently encountered in homes, as well as warehouses
and stores; it often is found in seed art or decorative dried "Indian
corn"
2. the adult is very small like a clothes moth, yellowish  white in
color with pale colored wings
3. the hind wing has a finger-like projection on the leading edge

The LESSOR GRAIN BORER is an internal feeder of the bostrichid
family.   This  family is more well  known  for  its  wood-boring
members.   The  lessor grain borer also  bores  into  wood and books as
well as whole grains.

*EXTERNAL FEEDERS
The  external  feeders are so called because the egg is laid outside the
whole grain, and the  larvae  bores its way in and feeds and develops
then inside the grain or product.  These insects are often found in
homes.

DRUGSTORE BEETLE
1. this beetle feeds on almost every dried plant product there is; it is
often found in dried dog food, and spices such as red pepper
2. the adult is light brown in color, about 1/10" long
3. it can be distinguished from the cigarette beetle that it resembles
by the longitudinal lines on the wing covers (elytron)
4. there will be one to four generations per year depending on
temperatures; under ideal conditions development takes about 40 days

CIGARETTE BEETLE
1. most common pest of stored tobacco; also infest most other dried
plant products
2. similar in appearance to the drugstore beetle except body is smooth
3. more prolific breeder than the drugstore beetle, and is a good flier

CADELLE
1. the largest of the food pests; is also known as the bread beetle or
bolting cloth beetle
2. the adult is shiny black in color, about 1/3" long, and the pronotum
is strongly separated from the wing attachments giving a "tractor and
trailer" appearance

TROGODERMA
1. T. Granarium, the Khapra beetle, is the most destructive of the food
infesting insects; many efforts are made to prevent this insect from
again becoming established in this country
2. some other trogoderma are quite well established already; the Cabinet
beetle (T. ornatum), larger Cabinet beetle (T. inclusum), and the
Warehouse beetle (T. variable). The warehouse beetle adult is brown to
black and about .12 inch in length.  The Larvae is about .25 inches and
has sharp pointed hairs which can cause severe gastric disturbances when
ingested in food.
3. if Khapra beetle is suspected, obtain verified identification
immediately and notify agricultural authorities

INDIAN MEAL MOTH
1. most common pest of dried fruit
2. adult is distinctive in appearance and behavior, about a3/4"
wingspread, outer half of forewings are reddish-brown in color, flies at
night in an irregular zigzag pattern
3. the larvae is about 1/2" long, dirty white color with a pinkish or
greenish tint; the mature larvae is often found searching for a suitable
place to pupate, they are often mistaken for clothes moths

*SCAVENGERS
The scavengers are so called because they are unable to penetrate or
feed on undamaged grain  kernels.  They  lay their eggs and the larvae
feed on dust and particles of food products, or on the kernels damaged
by  the internal or external feeders.

RED FLOUR BEETLE & CONFUSED FLOUR BEETLE
1. very similar in habits and appearance
2. red flour beetle is a strong flier, the last three antenna segments
form a distinct club
3. confused flour beetle, often called the BRAN BUG  does not fly, the
antenna segments gradually enlarge to a slender club end
4. both are reddish-brown in color, about 1/8" long
5. female lays up to 400 eggs in her lifetime of up to three years

SAW-TOOTH GRAIN BEETLE
1. the smallest of the stored food pests, it is able to easily penetrate
almost any package or jar after the original seal has been broken
2. adult is about 1/10" long, flattened body; brownish color
3. gets its name from the six saw-tooth projections on each side of the
thorax; merchant grain beetle very similar in habits and appearance
4. are found in almost any stored dry food material, large population
develops rapidly in normal household conditions
5. female lays about 300 eggs in her life of up to three years

MEDITERRANEAN FLOUR MOTH
1. common in household products such as nuts and chocolate as well as
spices, dried fruits, and flour
2. adult has about 1" wingspan, wings are pale gray with black wavy bars
running across them
3. when at rest, has a characteristic pose with the head elevated and
the tip of the abdomen protruding between the wings
4. silken threads or mats in infested material indicate this moth

*CONTROL/PREVENTION RECOMMENDATIONS

1. PREVENTION:  Purchase your grains and storage foods from a reputable
dealer.  Even so you will sometimes run into these stored insect
pests.   Nitrogen packed grains in sealed buckets should be safe from
infestation.  If you purchase bulk grains or dried fruits in other type
packaging, it is sometimes advisable to take steps to kill any  stored
product insects that may be in the packaging.  The first method of
making sure you have not brought any stored grain pest into your home is
by freezing the grain.  Freezing the grain at 0 degrees Fahrenheit for
4-7 days will kill most stored insect pests.   The other alternative is
to heat the grains.  Spread the grains out on a tray and heat in the
oven for 20 minutes at 150 degrees F (66 degrees C), or for two to three
hours at 120 - 130 degrees F (49-54 degrees C).   By heating the grains
you also dry them out, which is important if there is any question about
your grain being too damp.   Your grains should be placed into sealable
containers as soon as possible after purchase regardless as to whether
you take these other preventative steps or not.

2. Some suppliers sell pheromone traps, for monitoring many of the moth
species that infest stored grain.


3. THE INFESTED PRODUCTS MUST BE REMOVED AND DESTROYED; when inspecting
for infestation look for:
(a)  live or dead insects
(b)  webbing or silk threads
(c)  insect droppings in the bottom of a container
(d)  small holes in boxes or bags, sealed or not
(e)  flying moths
(f)  emergence holes in whole grains, or quantities of grain dust

4. after removal of the infested materials, all food particles and
residues must be thoroughly cleaned
5. If you so chose, a registered pesticide for this use, and apply to
cracks and crevices, and under shelving and behind paneling. (Often
these are the areas where the larvae will go to hide to pupate.)
6: It is normally advised not to eat food that has been contaminated
with food storage insects.  Insects and other pests can introduce
microbes into the food, and there may be an association between pest
insects and the development of mycotoxins.   This having been said, I
have often eaten foods that have had relatively minor infestations of
sawtooth grain beetles.  The infested grain products were used in
cooking, and no one was the wiser.  However if the grain has been
infested by any of the beetles in the Trogoderma family, you definitely
should NOT eat the grain; have the grain destroyed.  The larvae of all
of the Trogoderma beetles and especially the Warehouse beetle have sharp
pointed hairs, which can cause severe gastric disturbances when ingested
in food.   Any grains which have any mold, or rodent urine or feces need
to also be definitely destroyed and not eaten.
7. For large quantities of infested food material such as railroad cars,
ships, grain silos, pallets of bagged products, you may want to
investigate the hiring of a professional to fumigate the infested
product with methyl bromide or aluminum phosphide.  (Neither of these
products are available to the consumer and should only be handled by the
appropriately trained and licensed individuals.)




B) RODENTS
Comensal Rodents:
Comensal (Lives with man) Rodents are those rodents that have become
dependent on man for survival, as different from wild or feral rodents.
Over the centuries, these rats and mice have adapted to living in or
near our dwellings and farms, and eating our stored food and garbage.
They have caused more deaths and misery and economic damage than any
other group of vertebrates.


The  three  common  species of commensal rodents were first introduced
into this  country  from  Europe; during  the  Gold Rush period they
were brought into California in large numbers and have thrived in  this
climate.  Our cities, our suburban areas, and our farms have become
heavily populated.

Their  lives  are  designed  around survival.  They breed year round.
Their sight  is  poor,  but  their  highly developed sense of hearing,
touch, smell, and taste more than compensate.  They are very athletic
and  acrobatic with excellent balance, swimming, climbing, and burrowing
abilities.  They are very secretive, usually only seen  at night  unless
a heavy population is competing for limited food or nesting space.  Rats
will range one hundred  feet or  more  from the nest for food and
water.  Mice control only a small territory, and are often introduced
in  crates and boxes.  A large population may exist for some time before
anyone is aware of their presence.

An  infestation is usually detected by noticing one or more signs;
gnawed door corners or holes  in  walls, rub marks or swing marks from
their greasy bodies rubbing along a surface, spilled food, or their
fecal  droppings.  Sometimes their constant gnawing, necessary to keep
their teeth ground down, causes structural fires.

In addition to the physical damage caused by their eating and gnawing,
and the contamination from  their plague  is  probably  the  best known
and most feared, but salmonellosis  (food  poisoning),  murine
typhus,.  and  Weil's  disease  are  also a hazard.  While there have
been reports of rats biting people at  night,  they  will  usually only
attack  when  surprised  or cornered, then they will bite and scratch
fiercely.   An  infestation  of  commensal rodents should never be
ignored or taken lightly.

PHYSICAL CHARACTERISTICS

NORWAY RAT
1.   largest of the commensal rodents
2.   head and body 7 1/2" to 10" long, tail is shorter than head and
body
3.  weighs from 12 to 20 ounces
4 the coarse fur is grayish brown on the back and grayish white on the
belly; also called Brown rat, or sewer rat depending on the region.
5.   prefers to burrow so is built for digging; stocky body, small
close-set ears and eyes, and blunted  muzzle
6.   fecal droppings are 1/2" long, smooth with blunted ends
7.   live about 12 months
8.   female has two to four litters of eight or nine per litter
9.   prefers meats, fish, and grains for food, about one ounce per day
10.   needs more water than the roof rat, or about one ounce daily
11.   burrows often found along side of streams and ditches in coastal
and valley areas


ROOF RAT
1.   smaller and lighter than Norway rat
2.   head and body 6" to 8 1/2" long, tail is longer than head and body
3.   weighs from 8 to 10 ounces
4.   the color varies with the subspecies; the black rat is sooty black
on the back and gray below; the  Alexandrine is gray-brown on the back
and yellow-white underneath
5.   usually nests in the open or in trees and hedges so is adapted for
open living; large wide-spaced ears and eyes, the long tail for balance,
and a sharply pointed muzzle
6.   fecal droppings are 1/4" long, smooth with pointed ends
7.   live about 12 months
8.   female has two to four litters of five to seven per litter
9.  prefers fruits and vegetables as well as grains, about one ounce of
food and about one-half ounce of  water
10.  likes to live up in places; attics, etc., but will live wherever
they have to; found in the foothills up to 3,500'


HOUSE MOUSE
1.   resembles a miniature roof rat
2.   head and body about 2 1/2" to 3 1/2" long, tail is 3" to 4" long
3.   weighs less than one ounce
4.   dusky brownish gray color, slightly lighter underneath
5.   nests anywhere; may spend complete life in a box or a closet as
long as food and water is available;  male is very territorial in habits

6.   fecal droppings are 1/8" long; smooth with pointed ends
7.   live about 6-9 months
8.   female has six litters of five or six per litter
9.   prefers to feed on seeds and grains, needs little water; will
nibble when feeding and may feed 15 to 20 times per day
10.   may live outside in summer and move inside for winter

CONTROL OF COMMENSAL RODENTS

One  can consider rodent control from the standpoint of prevention
through environmental  management and  population  suppression.
Prevention is best, and environmental management is required as part
of  a  suppression operation.

There  are biological factors, behavioral factors, and environmental
factors to be considered in  designing a  rodent control program.  They
must be all weighed and allowed for or the control program will not  be
success-ful.

*BIOLOGICAL FACTORS

1. Rodents begin reproducing at a very young age, have large litters,
and breed year around (a)  a 90% population reduction may be replaced in
as little as 9 months
2.   The territorial movement of rats and mice tend to be quite limited
and their movement is usually only at night
a)  if live rodents are seen during the daytime it indicates that a
heavy population is present
(b)  rats normally range no more than 150 feet from the nest; a male
mouse will control an area of 10-20 feet from the nest
(c)  rats will migrate on their own; mice are often carried in boxes or
crates into new locations
3.   Rats rarely live more than one year; mice average 6-9 months.

*BEHAVIORAL FACTORS
1.   Rats and mice have poor sight, but their other survival senses are
extremely well developed
(a)  TASTE sensitive to fresh food; they remember foods that made them
sick in the past
(b)  SMELL sensitive to certain poisons and freshness, smell of man does
not frighten them
(c) HEARING very keen, can identify strange sounds and locate them and
they will adapt to any constant noise (including ultrasonics)
(d) TOUCH centered in the whiskers and guard hairs causes them to tend
to follow vertical surfaces when they travel
(e) PHYSICAL abilities of climbing, burrowing, and swimming enable them
to enter and survive most environments
2.   New object avoidance is a term that describes the tendency of rats
to be very cautious and wary of new objects introduced into their
surroundings  (such as bait boxes or traps) and or changes in the
surroundings
(a)  major sanitation programs should be done after the initial
suppression is performed
3.   Mice are very curious and will immediately investigate new objects
(a)  rearranging furniture or storage will encourage the mouse to go out
to inspect and remap the new arrangements
(b)  they are often caught in newly set traps


*ENVIRONMENTAL FACTORS
1.   Poor sanitation usually means abundant food, water, and harborage
is available so a population may become easily established; good
sanitation involves;
(a)  garbage and waste in closed containers with no spillage
(b)  stored foods in rodent proof containers
(c)  storage 6" off the floor and 18" clear of all walls
(d)  no structural defects or closed areas such as double floors, dead
spaces under cabinets, blocked corners, abandoned rooms or buildings
(e)  no outdoor harborage such as rubbish or debris piles, tall or thick
weeds, stacks of lumber, pallets, or boxes
(f)  no free water such as leaky faucets, standing water as in puddles,
toilet bowls or sinks
2.   Excluding the rodents from the structure is the most effective and
provides the longest term control; rodent-proof the building by
correcting:
(a)  openings under or around doors that are more than 1/2" for rats and
1/4" for mice
(b)  unshielded wooden doors or door frames (use metal kick plates and
in some cases metal door frames to keep rats from gnawing through.)
(c)  unscreened sewer drains
(d)  vines, shrubs, or trees touching or overhanging the structure
(e)  dirt floors or openings through floor to subarea
(f)  holes in walls or gaps around pipes or utility entrances
(g)  practices that permit rodents to be carried in with merchandise or
materials


*POPULATION SUPPRESSION THROUGH CHEMICAL POISONING AND TRAPPING

Suppressive  measures are considered as supplementary to and not a
substitute for  basic  environmental sanitation.

1.   TRAPPING is the preferred method of control when:
(a)  the use of chemical rodenticides is to be completely avoided
(b)  the animals may die in an inaccessible area and cause an odor
problem; anti-coagulant rodenticides do not cause the animal to go
outdoors to die
(c)  the last few survivors of a population refuse to take baits

2.   The classic snap trap or glue boards are effective for rats; mice
can also be caught by snap traps and glue boards, as well as the
Ketch-All repeating trap or the Tin Cat device

3.  mice are easily caught in traps; rats are more wary of new objects
so the technique of baiting an unset trap for several feedings is
effective in maximizing results
(a)  the best bait is that food that the rodents are eating now,
providing it can be affixed to the trap and can be kept fresh
(b)  baits for rats and mice include rolled oats, peanut butter, gum
drops, raisin bread, and bacon
(c)  cheese is not effective bait material
(d)  if food is not being taken, cotton balls or other nesting
materials, or shiny beads may be attractive, especially to mice.
4. set the trap against a wall or other vertical surface where the
rodents are traveling; use non-toxic tracking powder (talc or flour) to
determine the traffic patterns.  Like baiting with food, place the trap
with the trigger side against the wall and leave for several days before
setting the trap.
5.   CHEMICAL POISONING is the most common method of suppression and for
obvious reasons, I recommend using baits ONLY as a last resort. (There
are many situations where baits can be safely used, but due to the
complexity and potential hazard of baits, I do not recommend lay people
use them, but will cover the subject for academic reference.)
(a)  poison baits are hazardous to humans and non-target animals
(b)  only place poisons in areas or containers that are not accessible
to children and non-target animals
(c)  bait containers must be properly and visibly marked - this is a
required safety step
6.   many of the same considerations as in trapping apply
(a)  best bait is familiar food, or other solids or liquids
A. cereal grains, fish, meat, fruits or vegetables
B. if water is limited, use water as the bait with a little sugar added
for acceptance
7.   pre-baiting with the unpoisoned bait material will help overcome
shyness
8.   toxic tracking powder can also be used if food baits are not well
taken
(a)  as hazardous as food poisons so must be handled and applied with
the same considerations for safety

DEALING WITH INFESTED FOOD & CONTAMINATED AREAS:
All foodstuffs, which have show evidence that rodents have either eaten
or defecated or urinated upon, should be destroyed.

CDC Recommendations to protect yourself from communicable diseases
spread by rodents and their urine & feces are as follows:

Wear protective clothing, including coveralls, gloves, goggles and a
respirator. (Only a hepa filter respirator will filter out viruses)
Wear protective clothing when collecting dead rodents.  Rodents
collected (either already dead, or trapped) should be sprayed with
disinfectant (see below for recommendations), itās carcass placed inside
two plastic trash bags and disposed of in the garbage.  Snap traps
should be liberally sprayed with disinfectant if they are to be reused.

It is recommended that you use Lysol, or other disinfectants containing
diphenols as your disinfectant. Hospital disinfectants are effective if
they contain benzalkonium cloride.  Follow the label for the dilution
rates of the disinfectant you chose to use. You may also use a mixture
of one half cups chlorine bleach with one gallon of water.

Do not sweep up or vacuum areas containing rodent feces or urine.  Clean
up rodent waste using the disinfectants described above. Mop or sponge
the suspected area with the solution. Place your waste inside two
plastic garbage bags and throw away in an exterior garbage can.

Attics and subareas should be left alone using the method described
above . Take extreme care not to contaminate the living areas of a home
or structure with rodent feces and waste that may be found in and attic
or sub area.
(More information will be provided in the Health Pest FAQ)


Other Rodents:  Deer Mice

Deer Mice are of some importance due to the Hantavirus.  A full FAQ on
Hantavirus can be found in the yet to be released Health Pests FAQ.
Deer Mice (Peromyscus spp) are found throughout the nation..  Deer mice
are active all year, and are usually found in fields, shrubbery, and
wooded areas.  Though not normally found in structures they sometimes
nest in empty structures, and have been known to get into stored foods.
The first outbreak of Hantavirus in the US came about because of pine
nuts, which were contaminated with Deer Mice urine.  Deer mice are about
the same size as house mice but are easily distinguished. Deer mice have
a bi-colored tail and body.  The upper portion of the tail and body is
dark colored usually brown or in the case of juveniles, gray,), and the
underside of the body and tail is white.  The deer mice in California
have also been known to have fleas carrying the bubonic plague.  Though
Deer mice appear to be the primary vector for the Hantavirus , the virus
has been identified in the pinon mouse and chipmunks.

Follow all the safety precautions described above in this FAQ for
cleaning up and disposing of feces of rodents.


D) FUNGI & MITES

Both fungi and mites are pests, which appear only in moist grain.
Usually proper storage of grains will prevent these problems.   With any
of the fungi or mites, you should never try to eat the food, and it
should be disposed of.  Fungi cause mycotoxins in many stored foods.
Rather than to list these out, it is better said that any foods (with
the exception of cheese) should be thrown out if you suspect fungi
infestation.   Mite infestations are sign enough that you have a serious
moisture problem and most likely have fungi.  (There are one or two
mites used in grain mills to attack other stored product pests, but
these mites should not be present in any of your food storage.)

_____________________________________________________________

This is the first Rough draft of this FAQ.  Please send your comments,
criticisms, complaints, and suggestions to me at Paulsen
or post them to the newsgroup.  Please do not rely upon this FAQ or
refer to it until it is released in it's first "finished" version.

Once the first final release of this FAQ is ready I will develop and
release a draft "Health Pests FAQ".

Thanks for your input!

Eric
___________________________________________________________________




