Food and Fabric Pests

Apart from rodents, the pests which attack food and fabrics are primarily insects belonging to the orders Coleoptera and Lepidoptera - in other words, beetles and moths. There are about 100 species which are significant pests and, with few exceptions, these species are found throughout the world. This global distribution of food and fabric pests reflects the extent of international movement of people and products, which has resulted in these pests being carried far beyond their origins.

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Many of the pests of stored food are tropical or subtropical in origin and cannot resist low temperatures, but they can thrive indoors under the right conditions. Up to certain limits their rate of reproduction increases in direct proportion to increases in temperature and humidity. However, temperatures above 95OF inhibit development of most of these pests. Temperatures below 65 OF prevent the reproduction of pests such as flour beetles, which don't lay any eggs at these temperatures, and rice weevils, which lay very few.

The availability of water can also affect the survival of these pests. Some, such as flour beetles and the saw-toothed grain beetle, can thrive on food with only six percent water content, whereas rice and granary weevils need eight percent or more, and drugstore beetles require at least 10 percent moisture content. However, moisture contents above 15 percent may induce growth of molds which interferes with the development of some of these insects.

While many of these pests do not thrive outdoors in the United States, some such as the rice weevil can infest corn, rice or wheat in the fields in the South. Others, such as carpet beetles and larder beetles, scavenge harmlessly outdoors throughout the country, but become pests when they invade buildings and damage their contents. Many food and fabric pests feed on a wide variety of materials, but most have certain food preferences and some are very restricted in their diet.

While food and fabric pests may represent more of an economic threat where large quantities of food and fabrics are manufactured or stored, they also occur on a smaller scale as pests in individual homes. To some extent, the nature of the premises will determine the methods used to counteract food and fabric pests. Ironically, because of current government restrictions, these methods may be much more limited in a food plant than in a private home. However, in this Pest Management Report the focus will be more on homes and other premises where the professional can plan on using all the available procedures, without the artificial constraints imposed by government agencies in many food plants.

While it is important to know about the biology of every pest encountered, there are so many food and fabric pests that space limitations necessitate outlining the facts for just a few common pests representing the group. As mentioned earlier, most of these pests are beetles or moths which all share some similarities in their life cycles. For instance, beetles and moths both undergo complete metamorphosis. In other words, there are four stages in their life cycle: egg, larva, pupa and adult. The larvae are active feeders and in some species are the main stage causing harm. However, in many species of beetle the adults also feed and cause damage, though sometimes on different materials than the larvae. Most adult moths do not feed, although some may suck up liquids through their proboscis. The biology of the following pests will be outlined:

APPEARANCE: Dull, reddish-brown, cylindrical beetle, 1/10 inch long, with long snout and elbowed antennae. Two reddish-gold spots on each wing cover. Well developed wings and a strong flier.

LIFE HISTORY: Female bores a hole in the kernel of grain and deposits an egg. Up to 400 eggs are laid in a lifetime of three months or more. The larvae emerge from the eggs in a few days and feed inside the grain kernel. After three or four molts, pupation occurs inside the grain and after a few days the adults emerge. The whole life cycle takes about four weeks. Rice weevils are sensitive to cold and cannot survive outdoors in the North.

FEEDING HABITS: The larvae can eat all types of sound whole grain, including corn, rice, wheat, and rye, as well as peas, nuts and farinaceous products. Adults feed even more widely and can eat apples, pears, nuts, beans, cereals, flour, biscuits, bread and even tobacco. As with other primary feeders (i.e. pests which attack sound grain), the attacks of rice weevils can pave the way for secondary pests. Grain in the field as well as stored food are attacked. This is the dominant pest of stored food in the South.

APPEARANCE: Brown or blackish, cylindrical beetle, 1/10 inch long, with its large head bent under the thorax.

LIFE HISTORY: Females lay 300 to 500 eggs singly or in clusters in loose grain. The larvae eat their way into grain kernels and, after two to four molts, pupate there. Development is only possible above 730F; under optimum conditions the life cycle is complete in four weeks.

FEEDING HABITS: Adults can bore into sound grain kernels, where they may feed until only the shell remains. The larvae may feed on the flour produced by adult boring or may bore themselves. They are an important pest of whole grain, including wheat, rye, corn, rice and millet, but they are also known to breed in flour or other fine milled cereals which have been stored a long time.

These beetles include the saw-toothed grain beetle (0. surinamensis), the merchant grain beetle (0. mercator) and the rusty grain beetle (C. ferrugineus). These insects are so-called secondary pests of grain, attacking only damaged grain. They also eat grain products and other foods. The saw-toothed grain beetle is the most common and is described below:

APPEARANCE: Reddish-brown, slim beetle, 1/10 inch long, slightly flattened with six pointed projections on each side of the thorax (giving it a saw-like appearance). The wings are well developed but it is not known to fly (the closely related merchant grain beetle does fly).

LIFE HISTORY: Females lay about 150 eggs, singly or in small batches in crevices of food or loosely in ground food, over a period of about 5 months (some adults have lived over three years). The eggs hatch in about 8 days and the emerging larvae feed and molt two to four times before pupating. The pupal period averages about 6 days and the whole life cycle from egg to egg takes from four weeks to over four months, depending on nutrition, temperature and humidity. Optimum conditions are 860F to 95"F and high humidity; breeding ceases below 650F and at low humidity.

FEEDING HABITS: The larvae and adults thrive on processed or damaged food, including breakfast foods, flour, whole meal, dried fruit and sugar. It is commonly associated as a secondary pest with primary grain pests in granaries. The flat shape of the adults enables them to penetrate many packaged foods.

APPEARANCE: The confused flour beetle (T confusum) and the red flour beetle (T castaneum) are the most common species and they are both reddish-brown, slim beetles 1/8 inch long. Both have well-developed wings but the confused flour beetle is not known to fly, whereas the red flour beetle can fly short distances. They are further differentiated by the confused flour beetle having a straight-sided thorax and gradually enlarging antennae, whereas the red flour beetle has curved sides to the thorax and a very distinct antennal club.

LIFE HISTORY: Females of both species lay two or three eggs a day for a total of about 400 eggs in a lifetime. The eggs are laid loose on any available food. The eggs hatch in five to 12 days and the larvae feed and molt five to 12 times over a period of 22 to 100 days, depending on nutrition, temperature and humidity. The total life cycle takes from seven to more than 12 weeks; in warm buildings there are often five generations per year. The confused flour beetle is more common in northern states and the red flour beetle is primarily found in warmer parts of the United States.

FEEDING HABITS: These flour beetles, together with the saw-toothed grain beetle, make up an estimated 80% or more of flour mill insects. The larvae and adults cannot feed on whole, undamaged grain but can feed on flour, grain dust, dried fruit, nuts, spices, peas, beans, and even chocolate. They particularly feed on grain previously damaged by weevils or grain borers, but they can also attack grain which has developed cracks.

APPEARANCE: Reddish-brown, oval body, 1/10 inch long, covered in fine hairs. The wing covers are patterned with lines of dots and the antennae have a three-segmented club.

LIFE HISTORY: The female deposits eggs singly as they crawl on or bore through food. A total of 20 to 100 eggs are laid and these hatch in about 10 days. The emerging larvae feed, grow and molt four times over a period of two to seven months, and then make a cocoon of food particles in which pupation occurs. Pupation lasts 12 to 18 days and the emerging adults live two to six weeks. At room temperatures there are usually one or two generations each year.

FEEDING HABITS: The adults bore through materials but are not thought to feed. The larvae feed on a very wide range of materials, including bread, flour, spices and breakfast cereals. It is also recorded as eating leather, wool, hair, books and drugs. It can tunnel in wood and can perforate tin foil and sheets of lead.

Spider Beetles

LIFE HISTORY: Eggs are laid singly or in clusters on or near the larval food. The emerging larvae feed and molt three times over a period of about 90 days before spinning a debris-covered cocoon within which pupation occurs. In heated buildings two or three generations can be expected each year. Spider beetles are relatively resistant to cold and are common in northern states.

FEEDING HABITS: The larvae and adults are omnivorous and~are known to eat damaged grain, grain products, dried fruit, wool, hair, feathers, fish meal, cocoa, rodent droppings, spices and dead insects. They can also eat carpets and furs and have caused damage by tunneling into wood to pupate.

Among the most common carpet beetles are the varied carpet beetle (Anthrenus verbascl), the furniture carpet beetle (Anthrenus flavipes) and the black carpet beetle (Attagenus megatoma). Black carpet beetles are reportedly the most widespread and most destructive of all carpet beetles in the United States. With their black, oval bodies they are easily distinguished from the smaller, rounded, mottled bodies of the varied and furniture carpet beetles. Nonetheless, their life histories and feeding habits are similar. A biological profile of the black carpet beetle follows:

APPEARANCE: Shiny, black oval body, 1/6 inch long, with brown legs. Well developed wings and a good flier Larval carpet beetles have a characteristic hairy or wooly appearance.

LIFE HISTORY: Sixty to 90 fragile eggs are laid in hidden locations, such as in lint around baseboards, in hot air ducts and under furniture. The eggs hatch in five to 16 days. The larvae feed actively, avoiding light and molting five to 11 times over a period of nine to 23 months at room temperature. The larvae pupate in the last larval skin and pupation lasts about two weeks. The resulting adults may remain quiescent for two to 20 days before emerging, and then may live another 30 days.

FEEDING HABITS: The adults can live outdoors, feeding on pollen and scavenging in bird nests and on the remains of dead mammals and birds. They fly or are carried into buildings on flowers, etc., and larvae hatching from eggs laid by these invading adults can feed on a wide range of materials. Plant products eaten by the larvae include seeds, grains and cereals. Animal products are even more often attacked, including wool rugs, blankets, clothing, silk, felts, furs, skins, feathers, hair-filled furniture, meat, leather, milk powders, dead insects, books and dead rodents. Apart from direct feeding damage, carpet beetles may breach containers and make them vulnerable to insects which otherwise could not enter.

Webbing Clothes Moth

APPEARANCE: Adults have a wingspread of about 1/2 inch and when the wings are folded the insect is about 1/4 to 1/3 inch long. The wings are pale gold and the head bears fluffy, reddish-gold hairs and black eyes. There are no spots on the wings.

LIFE HISTORY: The females avoid light and lay eggs singly or in small groups among the threads of cloth, fastened by a gelatinous material which prevents easy dislodgement. A total of 30 to 50 eggs are laid in a period of one day to three weeks. The eggs hatch in four to 21 days and the emerging larvae are active and feed almost immediately. They often spin webbing as they move across the food material and, after molting five to 45 times in a period ranging from 40 days to two years, they spin a web in which they pupate. The pupation lasts eight to 44 days and after mating the female commences egg laying.

FEEDING HABITS: The adult moths do not feed, but the larvae have been reported feeding on a wide range of animal products, including furs, insect collections, wool, fish meal, woolen clothes and blankets, fingernail clippings, piano felts and lint accumulations. The webbing clothes moth is the most common of the moths which attack textiles. While they cannot digest vegetable products, they often damage cotton, linen and even paper during exploratory chewing or if these materials are dirty or coated with sizing or other attractants.

Tobacco or Warehouse Moth

APPEARANCE: Light, grayish brown, with two light bands across each forewing and uniformly gray hind wings. The wingspan is 5/8 inch.

LIFE HISTORY: Females lay about 100 eggs singly or in small clusters on or near tobacco or other food. The larvae cover the food in webbing and after molting about five times they migrate to crevices and other sheltered locations and spin a pupal cocoon. There are usually one or two generations a year in tobacco warehouses.

FEEDING HABITS: The highest-priced tobacco is attacked since this contains the most sugar. Tobacco that is not eaten is spoiled by webbing and frass adhering to the leaves. In addition to tobacco, many other dry vegetable materials are eaten, including nuts and dried fruits and to a lesser extent grains and flour.

Since they feed on any items containing grain, Indian meal moths are common pests found in pet stores. The Indian meal moth is a particular problem in bird seed, but can also be found in dry pet foods.

Let's take a little time to find out about this guy that spends your money so freely. This is one of the easiest stored food insects to identify because the adults have a colorful appearance and the larvae leave a silken webbing trail wherever they crawl. Newly emerged adults are bi-colored and measure about 1/2" from top to bottom.

Description

INTRODUCTION. The Indianmeal moth was given its common name by an early entomologist (Asa Fitch) who found it feeding on cornmeal (Indian meal). It is probably the most encountered pest of stored products found in the home and in grocery stores in the United States. Of Old World origin, it is now found worldwide.

RECOGNITION. Adults with wingspread (wing tip to wing tip) about 5/8-3/4" (16-20 mm). Wings pale gray but front wing with outer 2/3's reddish brown with a coppery luster.

Mature larva usually about 1/2" (range 9-19 mm) long. Usually dirty white but color may vary to a greenish or pinkish or brownish hue depending on its food, with head and prothratic plate/shield yellowish bron to reddish brown. With 5 pairs of well-developed prolegs on abdomen and each bearing crochets (hooks).

Prespiracular tubercule (wartlike area between spiracle and front edge of segment) of prothorax with 2 setae (hairs). Tubercule VI on mesothorax (wartlike area near and above leg) with one seta (hair). Body without pinnicula (dark or pale wartlike area at base of hairs or setae) on mesothorax, and 1st 9 abdominal segments.

BIOLOGY. Chiefly at night, the female lays 100-400 eggs, singly or in small groups, on the larval food material during a period of 1-18 days. Upon hatching, the larva establishes itself in a crevice of the food material. It feeds in or near a tunnellike case it has webbed together of frass or silk. The larval period lasts 13-288 days, depending primarily on temperature and food availability. When the last instar larva is ready to pupate, it leaves the food and wanders about until a suitable pupation site is found. There are usually 4-6 generations per year (range 4-8), with the life cycle (egg to egg) typically requiring 25-135 days (range 25-305).

HABITS. The adults cause no damage. The larvae are surface feeders and generally produce a lot of webbing throughout the infested part of the materials. They are general feeders and attack grain and grain products, a wide vriety of dried fruits, seeds, nuts, graham crackers, powdered milk, biscuits, chocolate, candies, dried red peppers, dried dog food, and bird seed. They are very destructive wherever dried fruits are stored. Preferred are the coarser grades of flour such as whole wheat, graham flour, and cornmeal, but they can breed in shelled or ear corn.

When the larvae wander about looking for pupation sites in homes, they are often mistaken for clothes moth larvae. Likewise, when the moths are flying, they are also mistaken for clthes moths. Adults are attracted to light.

CONTROL. follow the standard control procedures for stored product pests but remember that pupation takes place away from the infested food material.

This small, oval beetle is a common pest of dog food. Warehouse beetles feed primarily on animal products, but will readily feed on grain and cereal products.

Description

Larvae: are orange-brown in color and look hairy. The hairs of the larvae can cause allergic reactions in sensitive individuals especially when swallowed.
Adult: The adult is a tiny black beetle with white or lightly colored markings on its back.
Life Cycle: From egg to adult can be completed in 43 days, but they can stay in diapause (hibernation) for up to two years.

Trap Use and Placement: There is no exact number of traps that should be placed in a Pet Store to detect the presence or absence of insect pests. This will vary depending upon the size of the store and the number of rooms. In general, both types of traps should be placed 25-50 feet apart (3/1000 ft3) at eye level. Lures should be replaced every 60 days and traps should be replaced when necessary.

Spider Beetles

Webbing Clothes Moth

Tobacco or Warehouse Moth