'STORED PRODUCT PESTS 

Learning Objectives 
After completion of the study of Stored Product Pests, the trainee should be able to: 

Stored products can be infested at every point from their origin to final use; 

The most commonly attacked products are cereal grains, spices and nuts. Less commonly attacked are dried fruits, candy, rodent bait, dried dog food, dried decorative flowers and such diverse materials as museum artifacts, cosmetics, and drugs. Old, neglected, or hard-to-reach products provide the greatest potential for infestation and reinfestation. 

CONTROL AND MANAGEMENT 
Inspection 
In large facilities, a pest control technician will want to become familiar with the entire operation before making an inspection. The pathway a product takes is vitally important to detection. 
Pests can occur in machinery, stacked products, waste dumps, delivery spills, etc. In homes and retail businesses, excess clutter, bad lighting, storage areas with blocked access, and rooms located above or below infested materials are special target sites. 
All inspections should be conducted with strong flashlights. A knife, a good hand lens, screwdrivers and mirrors are also useful equipment. Flushing agents can be used, but care must be taken not to contaminate foodstuffs. 
Special attention should be given to all spills. Check for pests, cast skins, and tracks in spilled products or dust. Inspect the back of pantry shelves, floors under shelves, and all dark areas. 
Pheromone traps, available for nearly all stored product pests, should be used where routine inspections are made. 
Keep detailed inspection records. Written inspection findings and recommendations for changes by management or maintenance must be clear.
Be safe. Use bump hats and be careful of heat machines, and electrical hazards. 

Habitat Alterations 

Follow-up 
Ongoing monitoring and inspection plans should be put into effect in all food handling establishments. A complete pest management program is recommended for these operations. Clear communication with clients is important. Recommendations on cleaning and sanitation should be evaluated continuously.

PESTS OF WHOLE GRAINS AND SEEDS 
        Most stored product pests feed on readily available starch of broken or ground-up seeds and grains. Few species can chew through the strong seed coat or place eggs inside intact grains. Pests that can are: the rice and granary weevil, the Angoumois grain moth, the lesser grain borer, several species of seed beetles, or pea and bean weevils in the family Bruchidae. 

RICE WEEVILS AND GRANARY WEEVILS 
Sitophilus oryzae and Sitophilus granarlus 
These two similar snout beetles are found in stored whole grain throughout the United States. Adult beetles have snouts with jaws (mandibles) at the tip. With these jaws, females chew holes in the grain and deposit eggs. Larvae devour the inside of the seeds, pupate, and later, emerge to renew the cycle. Rice weevils (common in the southern states) can fly. Granary weevils (more common in cooler climates) cannot fly. These two weevils are more common in granaries and mills than in stores and homes, but they infest a wide variety of cereal grains and seeds that are found in storerooms, pantries, garages, and other storage sites. [The word "weevily" is still used in general reference to infested grain products whether or not the infesting pest is a weevil.]

Another weevil with a much longer snout infests acorns, pecans and hickory nuts. Acorn weevil larvae leave the acorns and nuts to pupate. When infested nuts are brought inside, fat white larvae often escape and wriggle across tables, floors, etc.

ANGOUMOIS GRAIN MOTH 
Sitotroga cerealella 
This buff, tan, or golden moth, with a wing span of 1/2 inch, is larger than the common golden-colored clothes moth. With wings folded it is more than 1/4 inch long. The Angoumois Grain moth is most commonly found in whole corn in the south and mid-west. Like the weevil, it is more often a problem in grain storage; but if whole corn is brought into homes or stores, sooner or later these moths are likely to become pests and fly about.

LESSER GRAIN BORER 
Rhyzopertha dominica 
A small cylindrical brown beetle about 1/8 inch long, this beetle is an important damaging pest of grain in storage or transport (trains, ships, etc.). Like many of its relatives (the Bostrichids, most of which are wood borers), the Lesser Grain borer has strong jaws and can chew through seed coats into grain where it completes its life cycle. This beetle is rarely a problem in urban homes or stores.

SEED BEETLES OR PEA AND BEAN WEEVILS 
    These beetles are not true weevils and do not have the weevil snouts. They infest only the seeds of one large plant family, the Legumes: peas, cowpeas, most beans (including mung beans). Each of these pests specializes in seeds of only one kind. 
     Most species measure 1/8 to less than 1/4 inch long. They are rather broad and have light and dark markings. They lay eggs on beans; larvae bore inside, devour the middle, then emerge through obvious 1/8 inch holes. The pest can be a problem in restaurants and homes. Infested and potentially infested legume seeds should be discarded.

PESTS OF GROUND, MILLED, OR PROCESSED GRAIN, SPICES, SEEDS AND NUTS 
This large group of pests [Some are called, "bran bugs."] infests stored products that have seed coats that are broken or removed by processing. [Potential infested products are listed with each species.] 

INDIAN MEAL MOTH 
Plodia interpunctella 
The Indian meal moth is a small colorful moth. Sitting on a wall, it is 1/3 inch long (somewhat longer with wings folded backward). The head and thorax is brown; the basal half of the wings are gray, and the last half coppery with dark bands. These moths can fly short distances indoors. Active flight for several days wears off most of the colored scales, but their gray band and coppery scales can be seen using a hand lens. Larvae, or caterpillars, grow to be about 1/2 inch long, cream colored (sometimes pinkish or greenish) with a brown head. Although not easily seen, fairly long hairs grow sparsely on each larval segment; when the larva is in a dusty environment, small particles will stick to the hairs. The Indian meal moth's life cycle is about two months.
 Infestations in packaged products start with small numbers; the longer the product is kept without use the larger the population grows.

 Larvae spin silk from their lower lip wherever they go. In large numbers, they can cover the top of a product with silk as they wander around on the surface. As a population grows, larvae may wander outside the package [often for long distances: from a room in lower levels, through holes in the floor into upper areas, from a pantry to the ceiling]; they may dangle from ceilings on silk strands. Their numbers, wandering habits, and large size easily distinguish Indian Meal moth larvae from the tiny Clothes moth larvae that do not wander openly. A pheromone that specifically attracts the flying Indian Meal moth is a very effective monitoring tool to use in warehouses and food service or retail sale food stores; in large areas, pheromone trap results reveal infested areas. 
        Indian meal moths infest most milled or ground cereals such as flour and cornmeal; all starchy processed products such as crackers, cake mixes, pasta, dog food, and rodent bait. They particularly respond to nut meats like pecans and walnuts, nuts in candy, powdered milk, some spices, and dried fruit. Products stored or unused for a long time are always primary suspects for infestations. 
         Control and management of these pests is the same as that for the Saw Toothed Grain Beetle (see below). 

SAW-TOOTHED GRAIN BEETLE 
Oryzaephilus surinamensis 
The saw-toothed grain beetle is a tiny, slender, dark-brown beetle that measures a little under 1/8 inch long. With a good hand lens, a pesticide applicator can identify three ridges that appear as fine lines on top of the thorax with six fine teeth on either side. Eggs are deposited on infested food and hatch into tiny white larvae. 

   At full growth, larvae are slightly smaller than the adults. They become covered with the material they infest and appear to be very small lumps. (Pupae are equally inconspicuous.) Larvae do not leave the infested material. Adults do, and while they do not fly, they wander in conspicuous numbers in the same vicinity as the infested material. [A similar species is the Merchant Grain beetle.] 
       Little harborage alteration is indicated. Older products will produce large populations simply because more generations develop over time. Saw-toothed Grain beetles infest the same materials as the Indian meal moth. Likewise, finding the infested product and cleaning the area of infestation is of prime importance. 
       Cockroach bait stations with a grain base may be useful in attracting and killing these beetles. [Capture in these bait stations may be the first indication of beetle infestation.] Pesticide sprays are of little use when infested material is discarded and cracks and crevices cleaned. 
Follow-up 
normally is not needed.

CABINET OR WAREHOUSE BEETLES 
Trogoderma species 
     In the same family as Carpet, Hide, and Larder beetles (see Fabric Pests, Chapter Five), Trogoderma and closely-related species (Cabinet, Larger Cabinet, and Warehouse beetles) principally infest grain-based products. One species, the Khapra beetle, is a very serious grain pest; routine federal quarantine inspections are made to prevent its entry and establishment in the United States. It has been known to build-up in large infestations. 
     Trogoderma adult beetles range from 1/16 inch to about 1/4 inch in length. They are about half as wide as long, which gives them an oval appearance. Their base color is black with three reddish-brown, golden, or gray irregular lines across the body. Larvae are stout and capsule-shaped; their segments are seen as stripes across the body. 
    Species that infest processed grain can be found in warehouses, storage rooms and homes. These beetles commonly infest cereal, spices, rodent bait, dry dog food, wheat germ and other processed cereal products with a high-protein content. 

Inspection 

Habitat Alteration 

Follow-up 
Set up regular monitoring programs in warehouses and food storage areas. [Pheromones for stored product infesting beetles are very helpful in such programs.]

CIGARETTE AND DRUGSTORE BEETLES 
Lasioderma serricorne, Stegobium paniceum 
These beetles are similar in appearance; while related to ' some wood borers or Powderpost beetles, their habits are quite different. Adult Cigarette and Drugstore beetles are oval, about 1/8 inch long and reddish-brown in color; they can fly. The Cigarette beetle is 

covered with tiny hairs that give it a golden" sheen. The Drugstore beetle appears dull and darker because of deeper lines on wing covers.
   Larvae are tiny, white, curved, and covered with infested material causing them to look like tiny lumps of the stored product. They are difficult to detect unless the product is dumped and sifted. These beetles are commonly found in spices (paprika, ground pepper, ginger), milled cereals (flour and cornmeal), dry dog food, cosmetics, drugs, as well as some human poisons, pyrethrum dusts, and dried flowers (through the glue that attaches the flower head to wire stems). In homes, spices are favorite foods, especially paprika.

Locate the infested material (beginning with spices) and discard all infested products. 
Follow-up is seldom needed.

FLOUR BEETLES 
Tribolium castaneum and T. confusum 
Two common species of similar flour beetles infest dry milled cereal products in flour mills, retail food stores, and homes. Other closely related species are found from time to time, but the two that are best known are the Red Flour beetle and the Confused Flour beetle. These beetles are about 1/8 inch long, reddish-brown in color, with short, stout antennae. Larvae are slightly longer than adults, creamy-white, with few hairs. Only those flour mills with the most thorough cleaning programs keep populations of Flour beetles low. [These beetles can live on flour spills.] Packaged milled cereals such as flour, cornmeal and cake mixes bought in large quantities may be stored long enough to allow eggs or larvae that have slipped through the milling and packaging process to develop.


Control and Management

PESTS OF MOLDY, DAMP, OR OUT-OF-CONDITION GRAIN AND GRAIN PRODUCTS 
      Milled or ground cereals and cereal-based products become heavily infested with fungi and bacteria when their moisture content is high. Many insects feed on the decaying organic matter that involves starches, proteins, certain vitamins, and other chemicals produced in the process of decomposition by microorganisms. Spoiled products may include animal foods, milled cereals, flour spills, caked milled grain. Pests can be found in unclean grain storage elevators, barns, and mills as well as in kitchen pantries and cabinets with moisture leaks or ineffective ventilation. The infesting pests are scavengers whose nutritive requirements are met by fungal-infested cereal products; they can develop into large populations. These pests include grain beetles, mealworms, and mites. Two merit special attention:

PSOCIDS 
         Psocids are tiny, pale gray or yellowish-white, wingless, soft-bodied insects little more than 1/16 inch long. They feed primarily on mold that grows on decomposing starchy materials. Psocids are sometimes called "book lice" because they are found in great numbers on books and papers sized with starch and stored in damp situations. Psocids require a minimal relative humidity of at least 60 percent; t h i s level accomplishes two purposes: the moisture keeps the Psocids from drying out, and it promotes the mold or fungal growth on which they feed. A relatively high humidity can be maintained in poorly-ventilated rooms, closets ' basements, cabinets and pantries with a moisture source. To eliminate Psocids, discard the starchy source of mold and dry out the storage area.

GRAIN MITES 
The most common grain mite is called Acaras siro. These tiny tick relatives look like dust with a slightly brownish tinge. A constant humidity level is even more important to Grain mites which prefer relative humidity's between 75 and 85 percent. Grain mites are almost colorless but have long microscopic hairs. When they molt, the hairs of the cast skins cling to those of others. [They can pile up in a fluffy ball the size of a man's palm. A population of that size can be produced in a humid kitchen cabinet with as little as a scant dusting of flour over the shelf.]

     Like Psocids, Grain mites can be eliminated by discarding infested materials and cleaning and drying out the chamber. Grain mites have been known to be responsible for allergies like those caused by house dust mites in humid homes. Use preparations containing tannic acid (carpet cleaners or brewed tea) applied to mite cast skins to suppress this protein allergy.







SUMMARY

Stored product pests include a wide range of insects that feed on grain, seeds and other plant parts that are stored, milled, or processed. Some of these pests infest stored products at every point from their origin in fields to granaries, mills, processing plants, warehouses, retail stores, food serving establishments, and homes. Some species of stored product pests can feed on the whole intact grain. Most can only feed on grains that have been broken or milled, and some feed on processed herbs and spices. Each pest species has a preferred environment and group of foods. Stored product pest infestations are not easy to discover when populations are low or building up. Pheromone traps (traps that use specific attractants) are very helpful in monitoring stored products in a pest management program. Locating and discarding infested products in homes and restaurants is a common method used in stored product pest control.

STUDY QUESTIONS FOR MODULE ONE CHAPTER FOUR STORED PRODUCT PESTS

1 . Some common stored product pests that attack whole grains and chew through the seed coat are
A. rice and granary weevils
B. red and confused flour beetles
C. psocids and grain mites
D. sawtoothed and merchant grain beetles

2. Pheromones are used in
A. sprays
B. traps
C. dusts
D. warehouses

3. is not commonly a food of stored product pests.
A. dried fruit
B. paprika
C. paper products
D. cornmeal
E. mung beans

4. Psocids and grain mites need to build large populations.
A. grains
B. processed meal
C. high protein grain
D. high humidity.