Orchard Pest Management species list -- Elizabeth H. Beers and Geraldine Warner (originally published 1993) Insects and mites belong to a large group of animals known as arthropods. Several characteristics differentiate insects from other arthropods. The body is segmented, and the segments are grouped into three sections: head, thorax and abdomen. The eyes, antennae and mouthparts are on the head, and the legs and wings are on the thorax. In contrast, mites have no antennae, and adult forms usually have four pairs of legs. The head and thorax are smaller and fused in mites. The abdomen is relatively large and bulbous and is not distinctly segmented. An insect's skeleton is on the outside of its body and is called an exoskeleton. It serves as a support for muscles and internal organs as well as a covering. The body wall of an insect has three layers. The outer layer is cuticle containing chitin, proteins and often pigments. This is secreted by a cellular layer beneath it called the epidermis. The inner layer is called the basement membrane. The type of mouthparts an insect has determines how it feeds and what sort of damage it does.

There are two general types: chewing and sucking. Insects with sucking mouthparts suck liquid food through an elongated beak. Insects with chewing mouthparts tear off pieces of host tissue and ingest it. Growth progresses through successive stages. Females lay eggs, which hatch into an immature stage. After passing through a series of immature stages, the insect emerges as an adult. Adults mate and the cycle begins again. Most insects start as eggs, which vary in size, shape and color. They can be deposited singly or in compact masses but are usually protected in some way. They may be laid in the ground or in or on plant tissue. Eggs left exposed are often protected from the elements and natural enemies by a coating. Eggs may be round, oval, barrel shaped, disk shaped or suspended on long stalks. The tough outer surface protects the embryo and prevents water loss. The first immature stage of the insect hatches from the egg. As the insect's rigid exoskeleton cannot expand much, it must be shed and replaced with a larger one as the insect grows. This process is called molting. The life stage between each molt is called an instar. Molting is governed by hormones.

Cuticle secretion and the molt cycle are controlled by ecdysone, a steroid hormone. The hormone is secreted by a gland in the thorax, which is in turn controlled by a hormone from the brain. Whenever the brain receives the appropriate stimulus, the insect will molt. A new cuticle forms under the old one, then the old exoskeleton splits and the insect wriggles its way out. Many insects eat their own discarded skin. The new cuticle is soft at first. The insect may swallow air to expand its own volume and stretch the new exoskeleton before in hardens, usually within about an hour. Metamorphosis Most insects change in form during their development, and the successive stages are not all alike. This change in form is called metamorphosis. It is controlled by a juvenile hormone secreted by glands in the insect's head. The juvenile hormone is released during each molt, but the amount decreases each time. As the concentration of juvenile hormone declines, more adult characters will appear until very little or no juvenile remains and the adult stage is produced. If the juvenile hormone is introduced at the wrong time or in the wrong amount during the insect's life cycle, normal growth can be disrupted.

Insect growth regulators use this principle for pest control (see section on Insect Growth Regulators ). Some insects change very little in form, and the young and adults are similar except for size. This type of development is known as simple metamorphosis. The young, which are called nymphs, usually share the same habitat and feed on the same host as the adults. Nymphs lack wings and reproductive organs. Aphids and leafhoppers are among the insects that go through simple metamorphosis, as do mites. Some insects have young and adults that are quite different in appearance from each other and often live in different habitats. This type of development is known as complete metamorphosis. The young are called larvae. Larvae generally have chewing mouthparts, even when the adults have sucking mouthparts. The larva goes through a series of stages, finally transforming into a pupa before becoming an adult. The pupa does not feed and is usually inactive. Many insects pass the winter in the pupal stage before emerging as adults. Insects that go through complete metamorphosis include moths (whose larvae are caterpillars), flies (whose larvae are worms or maggots) and beetles (whose larvae are grubs).

The metamorphosis of some insects is somewhere between simple and complete. These include thrips and male scale insects. The length of a generation and how it is influenced by the seasons varies from insect to insect. Many insects have one generation each year. However, some beetles and moths need two or three years to complete one generation. Other insects have more than one generation each year. In some cases, the insect has a constant number of generations. In others, the number of generations may vary depending on the climate. A few insects, such as aphids, have many generations each year and keep reproducing as long as the weather is favorable. In most cases, the insect passes the winter in a state of dormancy. The overwintering stage can be the egg, nymph, larva, pupa or adult. Dormancy can last from days to years. It can be triggered either by environmental or genetic factors. Most insects go into dormancy when the weather becomes unfavorable and become active again when it turns favorable. Others will go into dormancy at a certain time of year before conditions become unfavorable. This is known as diapause. Diapause is often triggered by the shortening days as winter approaches.

Many insects require a prolonged period of chilling before they will break diapause. Reproduction in Insects and Mites Reproduction in insects and mites can take a wide variety of forms, often very complex. Some can switch their type of reproduction during their life cycle based on environmental triggers. Others reproduce the same way throughout their life history. The basic theme, and some of the variations are described below. Sexual reproduction: The standard model for reproduction is where males and females occur throughout the life cycle, and each produces a germ cell (egg and sperm, respectively). The male inseminates the female during mating. The female often stores sperm in special pouches in her abdomen called spermathecae (singular, spermatheca). The eggs are fertilized within the female's body, producing an embryo. Eggs are deposited on a host. They hatch and develop into either male or female offspring. Parthenogenesis: This is asexual reproduction, where eggs grow and develop without fertilization. There are several variations of parthenogenesis. Arrhenotokous parthenogenesis is where unfertilized eggs produce only males. In deuterotokous parthenogenesis, both males and females are produced from unfertilized eggs.

In thelyotokous reproduction, unfertilized eggs produce only females. Spider mites, for example, undergo arrhenotokous parthenogenesis, where unfertilized eggs produce males and fertilized eggs produce females. External insemination: Insects may reproduce by sexual means, but insemination occurs without mating. The males deposit spermatophores, which are packets of sperm, and the females extract the sperm from these packets by various means. Rust mites undergo external insemination. Viviparity: Most insects deposit eggs that hatch into nymphs or larvae, a process called oviparity, but some insects bear living young. A common example are aphids, which are viviparous during part of their life cycle. A variation is ovoviviparity, where eggs are held within the female's body, where they hatch, and the young are born live. Polyembryony: This is where two or more embryos develop from a single egg, as in the parasitic Hymenoptera, such as braconid, encyrtid, and dryinid wasps.

Typically, between two and several dozen embryos are produced, but some encyrtids can produce up to 1,500 embryos from a single egg. ENT 425 | General Entomology | Resource Library (Tutorials) deon branch Reasons for Success It is certainly no accident that insects are the most abundant and most diverse group of organisms on earth. They have maintained a position of ecological pre-eminence for over 400 million years: they have witnessed the rise and fall of dinosaurs; they have survived at least four major cataclysms that resulted in planet-wide extinctions; and they continue to thrive despite mankind's best efforts at eradication. While no single ecological or physiological attribute can account for this unparalleled success, the insects do have a unique combination of characteristics which, as a whole, have given them an unusual survival advantage. In brief, these attributes include an exoskeleton, small body size, the ability to fly, a high reproductive potential, complete metamorphosis, and adaptability in an ever-changing environment. Exoskeleton Unlike vertebrates, an insect's supporting skeleton is located on the outside of its body.

This exoskeleton is a marvelous structure that not only gives shape and support to the body's soft tissues, but also provides protection from attack or injury, minimizes the loss of body fluids in both arid and freshwater environments, and assures mechanical advantage to muscles for strength and agility in movement. As a "suit of armor", the exoskeleton can resist both physical and chemical attack. It is covered by an impervious layer of wax that prevents desiccation. Much of the exoskeleton is fabricated from chitin, a polysaccharide that binds with various protein molecules to form a body wall that may be as flexible and elastic as rubber or as hard and rigid as some metals. Freedom of movement is ensured by membranes and joints in the exoskeleton. Muscles that attach directly to the body wall combine maximum strength with near-optimum mechanical advantage (leverage). The result is an ant, for example, that can lift up to 50 times its own body weight. Small Size In general, the insects are marvels of miniaturization.

Most species are between 2 and 20 mm (0.1 - 1.0 inch) in length, although they range in size from giant moths that would nearly cover your computer screen to tiny parasitic wasps that could hide inside the period at the end of this sentence. Dichomorpha echmepterygis is the smallest of the small. Discovered in 1997, this Costa Rican wasp (family Mymaridae) is a parasite of other insects' eggs. Adult males may be only 0.139 mm (0.00055 inch) in length -- nearly 1/3 smaller than some single-celled protozoa (e.g., Paramecium caudatum). Smallest Insects For an animal with an exoskeleton, small size is a distinct advantage. If insects were as large as cows or elephants, their exoskeleton would have to be proportionately thicker to support the additional mass of body tissue. But a thicker exoskeleton would also be heavier and more cumbersome. Even the simplest movements would require a larger muscle volume and consume more energy.

Since a two-fold increase in body length typically results in a four-fold increase in surface area and an eight-fold increase in volume and mass, there is an upper limit to how large insects can become (somewhere around 125-150 grams). Beyond this size, the insect's surface area is just too small for attachment of all the additional muscle tissue. "Mothra" and "The Fly" may be entertaining on the movie screen, but in real life they'd never get off the ground!! Trail left by the larva of a leafminer Another advantage of small size is the minimal resources needed for survival and reproduction. A crumb is a feast; a dewdrop quenches thirst; a pebble provides shade. In some cases, food requirements are so modest that an insect may live on a single plant or animal for its entire life and never exhaust its food supply. A leaf miner, for example, spends its entire larval stage tunnelling within the paper-thin layer of cells (parenchyma) between the upper and lower epidermis of a single leaf. In some ant species, an entire colony may live inside a single acorn or plant gall.

Parasitic wasps in at least seven families of Hymenoptera complete their entire development within the eggs of other insects. Biggest Insects Finally, small size is a big advantage to insects that must avoid predation. They can hide in the cracks of a rock, beneath the bark of a tree, behind the petal of a flower, or under a blade of grass. The exoskeleton is hard enough for them to burrow between individual grains of sand, yet flexible enough to let them squeeze through the tiniest of cracks. Small size, together with adaptations in body shape and coloration, gives many species the ability to blend so well with their environment that they become virtually undetectable. Flight Insects are the only invertebrates that can fly. Judging from the fossil record, they acquired this ability about 300 million years ago -- nearly 100 million years before the advent of the first flying reptiles. Flight gave these insects a highly effective mode of escape from predators that roamed the prehistoric landscape. It was also an efficient means of transportation, allowing populations to expand more quickly into new habitats and exploit new resources.

The forces of natural selection have shaped insect flight into a remarkably efficient process employing principles of aerodynamics that human engineers do not yet fully understand. Although the metabolic cost of flight (calories per unit of lift) is similar to that of birds and bats, an insect's flight musculature produces at least 2X more power per unit of muscle mass (see chart below). This high efficiency is largely due to elasticity of the thorax -- 90-95% of the potential energy absorbed by flexion of the exoskeleton is released as kinetic energy during the wing's downstroke. Efficient use of energy allows some insects to travel great distances or remain airborne for long periods of time. More than 200 species, including moths, dragonflies, locusts, flies, and beetles are known to migrate over long distances by air. The migratory locust, Schistocerca gregaria, can fly for up to 9 hours without stopping. Large swarms occasionally traverse the Mediterranean Sea. In North America, annual migrations of monarch butterflies (Danaus plexippus) wing their way from summer feeding grounds to overwintering sites in California and Mexico.

One individual, marked in Ontario, Canada was collected four months later in Mexico, 2800 km from its birthplace. Speed and manuverability are traits usually associated with the more highly advanced orders of insects, but some primitive insects (notably the dragonflies) are remarkably agile fliers: they can hover, turn while hovering, and even fly backwards or sideways. For their size, some species are remarkably swift. Large hawker dragonflies (family Ashnidae) have been clocked at a top speed of 58 km/hr (36 mph) over level ground. By comparison, the fastest human sprinters run only about 36 km/hr (22.5 mph). The wings of a large insect can generate a considerable amount of lift. Green darner dragonflies (Anax junius) are able to fly while carrying a load up to 15 times their body weight. Insects with smaller wings have to work much harder to remain airborne. Some of the tiny biting midges (like Forcipomyia spp.) beat their wings over 1000 times per second. A special type of muscle tissue is needed to sustain this rapid rate of contraction.

Reproductive Potential Reproductive success is one of the most significant measures of an organism's fitness. In insect populations, females often produce large numbers of eggs (high fecundity), most of the eggs hatch (high fertility), and the life cycle is relatively short (often as little as 2-4 weeks). Together, these three characteristics enable insects to produce remarkably large numbers of offspring. A typical female lays 100-500 eggs in her lifetime, but numbers in the thousands are not uncommon. The queen of an African termite colony may be the mother of more than ten million workers during her 20-25 year lifespan. Antoni van Leeuwenhoek, the Dutch scientist who first discovered single-celled organisms, was probably the first person to comprehend the reproductive potential of insects. In 1687, he reared blow flies (probably Calliphora erythrocephala) on a diet of owl meat and found that females produced an average of 144 progeny: half male, half female.

Using this data (and assuming no mortality), he calculated that a single pair of flies could give rise to 10,368 offspring in the third generation, 746,496 in the fourth generation, 53,747,712 in the fifth generation, and 3,869,835,264 in the sixth generation. At this rate, the fly population would grow to more than 1 X 1017 individuals in one year (10 generations). In two years of continuous reproduction the flies would fill a ball nearly 8 million kilometers in diameter. Calculations like this are completely unrealistic because they ignore all the limiting factors (like food supply, predation, climate, and disease) that keep natural populations in check. But the numbers do illustrate how quickly insect populations can grow, and they help explain why pest outbreaks often seem to develop so suddenly. Since most insects die before they ever have an opportunity to reproduce, a high reproductive potential is the species' best chance for survival. Many adaptations help maximize this potential. Most females, for example, can store sperm for months or years within the spermatheca, a special region of the reproductive system.

A single mating can supply a female with enough sperm to fertilize all the eggs she will produce in her lifetime. An unbalanced sex ratio, where females outnumber males, is another way to maximize reproductive potential. Since most insects are not monogamous, a few males can supply sperm for a large number of females. And finally, there are many species (e.g. aphids, scale insects, thrips, and midges) where males are entirely absent -- all members of the population are female and contribute offspring through a process of asexual reproduction. Life cycle of the house fly Most insects undergo significant developmental changes as they grow from immatures to adults. These changes, collectively known as metamorphosis, may involve physical, biochemical, and/or behavioral alterations that promote survival, dispersal, and reproduction of the species. In the more primitive insects, most of these changes occur gradually as the animal matures: organs of reproduction and flight develop incrementally during the immature stages and become functional only in adults. Since this transformation process is slow and does not include all body tissues (incomplete metamorphosis) the immatures and adults share many characteristics -- they often live in similar habitats and feed on similar types of food.

More advanced insects, however, undergo complete metamorphosis -- a dramatic transformation in form and function between the immature (larval) and adult stages of development. In these insects, a larva is primarily adapted for feeding and growth. It assimilates energy reserves which, in some cases, will sustain the insect for the rest of its life. When fully grown, a larva molts into a transitional stage, called the pupa, and begins a period of massive internal and external reorganization. Body organs and tissues encoded by larval DNA are disassembled and rebuilt according to a second DNA blueprint that had been repressed during larval life. An adult insect (imago) eventually emerges from within the pupal exoskeleton bearing little or no resemblance to its larval form. Its primary function is dispersal and reproduction. In the class Insecta, only 9 out of 28 orders undergo complete metamorphosis, yet these 9 orders represent about 86% of all insect species alive today. The obvious advantage to this type of development lies in the compartmentalization of the life cycle. Through natural selection, larval form and function can be optimized for growth and feeding without compromising adaptations of the adult for dispersal and reproduction.

Each stage of the life cycle is entirely free to adapt to its own ecological role. In some cases, this means that immatures and adults may consume different types of food, exploit different environmental resources, and even occupy different habitats. Adaptability A combination of large and diverse populations, high reproductive potential, and relatively short life cycles, has equipped most insects with the genetic resources to adapt quickly in the face of a changing environment. Their record of achievement is impressive: they were among the first creatures to invade the arid expanses of dry land and exploit green plants as a source of food, they were the first animals to use flight as an escape from predators, and they were the first organisms to develop a complex social hierarchy with division of labor and cooperative care of the young. As a group, they have endured 400 million years of climatological and geophysical upheaval, including the evaporation of inland seas, formation of mountain ranges, shifts in continental plates, onset of ice ages, and the fallout from cosmic impacts. Adaptation is an ongoing process. Populations must continually change as new resources appear and old ones disappear.

Just within the few thousand years since humans began roaming the earth, insects have acquired a taste for new products that would never be a part of their "natural" environment: e.g., glue and wallpaper paste, book bindings, cardboard, paintbrushes, tanned leather products, the corks of wine bottles, mummies, stuffed museum specimens, chocolate, ginger, yeast cakes, tobacco, pepper, and even potent drugs like marijuana and opium. In the early 1900's, a powder post beetle (Scobicia declivis) made itself a nuisance by gnawing holes through the lead sheath around telephone and telegraph cables. Once inside the cable, these "short-circuit beetles" ate the fiber insulator around the copper conductor. After enough insulation was gone, the wire would touch the lead sheath and create a short-circuit in the line. The high cost of replacing damaged cable eventually forced the telephone company to develop non-fibrous insulators for their long-distance cables. Perhaps the most remarkable example of insect adaptation in this century has been the speed with which pest populations have developed resistance to a broad range of chemical and biological insecticides.

After World War II, public health officials in the United States made a concerted effort to eradicate the house fly (Musca domestica) with DDT. For several years the campaign seemed promising: fly populations decreased and optimism ran high. But a few resistant flies managed to survive because they were endowed with an enzyme that could detoxify DDT. These survivors reproduced and passed this resistant trait to their offspring. In time, DDT-resistant flies repopulated their environment and the species now appears to be living happily ever after! Significant levels of pesticide resistence have now been reported in over 500 insect species, and many of these animals are resistant to compounds from more than one chemical family. In New York, for example, potato growers on Long Island must cope with a population of the Colorado potato beetle (Leptinotarsa decemlineata) that is resistant not only to organophosphates, carbamates, and synthetic pyrethroids, but also to some of the insect growth regulators and microbial insecticides. Development of insects Insect identification > Development of insects Development of insects Most insects lay eggs which hatch after a longer or shorter time into the young.

In some cases the egg appears to be retained within the body of the parent until after it has hatched, and then the young are produced in a stage able to move about. Insects in which this is true are termed ovoviviparous, the others being oviparous. Insect eggs are usually very small, vary greatly in form and may be laid singly or in clusters (Fig. 31). They are covered by a chitinous shell, the chorion, which often bears markings in the form of ridges, reticulations, etc., and frequently they are also colored. At one place on the surface is a minute opening or group of openings through the shell, called the micropyle, believed to be for the entrance of the fertilizing sperm. The length of time spent in the egg differs in different insects from a few hours to many months, and in some cases the eggs do not hatch until the second season after they are laid. In hatching, the shell breaks and out of it crawls the young insect, in the majority of cases quite unlike the adult it is to become. In order to reach maturity it must now grow and undergo changes in structure and appearance.

These together are expressed by saying that most insects in order to become adult undergo a metamorphosis. In some of the simpler insects, a few changes and growth only are needed to make them mature, and these are therefore usually grouped together as the Ameta�bola, or insects having practically no metamorphosis. The remaining insects, from this standpoint, form two groups: those which on hatching generally show some resemblance to the adults and reach maturity by a certain series of changes; and those which on hatching are totally unlike the adults and become adults by a somewhat different process. These groups are known as the Hemimetabola, or Pauro�metabola, and the Holometabola, respectively, these names suggesting the amount of metamorphosis required for members of each group to become adult. A member of the group Ametabola, upon hatching, will begin to feed and grow. Growth, however, is restricted because the insect is enclosed by chitin which, while elastic to some extent, at least at its thinner portions, has its limitations in this regard.

In some cases the insect is able to reach its adult size within the chitin, but in other cases this proves impossible, and a process called molting takes place. This is begun by pouring out of fluid by the outside layer of living cells, the hypodermis, between it and the chitin, separating the two. Next a split in the chitin appears somewhere, usually along the back, and the insect crawls out of its skin, i.e., molts. It is now soft and unrestricted by an outer shell and grows rapidly. A new chitinous shell begins to appear and is completed in a short time (within a day or so) and thereafter only such growth is possible as the elasticity of the new shell will permit. In most of the Ametabola, molting as thus described is not usual, the shell being sufficiently thin to stretch the amount needed for growth to adult size (Fig. 32A), though sometimes two or even three molts may occur (Fig. 32B). In both cases, however, the reproductive organs appear not to be mature at the time of hatching and only gradually become so during the period following. In a few cases molting seems to occur at intervals throughout life.

In the Hemimetabola (or Paurometabola) the young insect on escaping from the egg, though resembling its parent to some extent, must, never�theless, undergo many changes in structure and a considerable increase in size as well before reaching maturity. Thus a young short-horned grasshopper, on hatching, will need to grow to be about ten times as long before becoming adult; it is without wings, which will need to be developed; its reproductive organs are not mature and must become so; and other differences occur. All of these must be transformed into their condition in the adult; and to accomplish this, energy is necessary. In the egg the energy for development has been provided by the yolk; after hatching the young insect must provide it by gathering food. The young insect, therefore, soon after hatching seeks for food and having found it begins feeding. The nourishment thus obtained results in growth so far as this is possible within a shell which is tightly fitting and only to some degree elastic. When no further growth in this way can occur and the body has stored within it all the materials needed for a greater increase in size, it proceeds to molt in the manner already described for the Ametabola.

On escaping from its old skin or shell, however, besides a rapid increase in size, changes of structure also occur, so that a difference in appearance now becomes evident. These changes must be produced quickly, as the hypodermal cells of these parts, as well as of all the surface, are producing a new chitinous skin; and when this has once hardened, no further changes and little further growth are possible. Molting, then, marks the beginning of a brief period - a day, more or less - of increase in size and of changes in appearance, these last all being in the direction of making the young insect more nearly like the adult it is to become. When the new shell has become hardened, the insect resumes its feeding. After another feeding period the young insect is again confronted with the same difficulties as before, and it meets them in the same way, by molting, and immediately thereafter, before its new shell has hardened, it seizes the opportunity to grow and change its appearance further. Finally, after some molt, full adult size for the insect is attained and all its organs have also fully developed and matured, producing the adult insect itself (Figs. 32C, 33).

Thus the young insect becomes an adult by alternating periods of feeding, with brief periods of molting, following which growth and change take place, the total of which produces the adult. The number of molts, and consequent opportunities for change which occur, varies in different Hemimetabola. There may be only 2 or 3 in some kinds; 5 is perhaps the average number though more are not uncommon, and 21 are known to occur in one species. Certain names for these different conditions are convenient for use. The feeding periods between the molts (or ecdyses) are called instars, so that the progress of an insect from hatching to adult is by an alterna�tion of instars and molts. The insect itself, from hatching until maturity is generally called a nymph. Figure 33 shows the changes in appearance of a grasshopper after each molt. Some entomologists have removed from the Hemimetabola those groups whose young develop in water, this aquatic life having resulted in making these young differ greatly from their adults.

For the group thus formed they have also taken the name Hemimetabola, which leaves the other insects of that former group without a name and for them they have suggested the term Pauro�metabola. If this classification be accepted we should have four groups: the Ametabola; the Paurometabola, which would include all of the Hemimetabola as the term is used above except those whose young live in water; the Hemi�metabola, which would include those whose young live in water; and the Holo�metabola, which have a complete metamorphosis. This division of the groups has not as yet been universally adopted. With the remaining group of insects, the Holometabola, while there is a little similarity in the metamorphosis to that in the Hemimetabola, there are also many differences. When a young Holometabolous insect hatches, it in no way resembles its adult. A caterpillar is totally different in appearance from the butterfly it finally becomes; the white grub in the earth is in no way suggestive of the June bug (May beetle) into which it transforms.

Nevertheless, this young insect - called a "larva" - has to meet the same problems of growth and transformation to the adult condition as do the Hemimetabola and uses the same means for accomplishing the needed results, viz., the utilization of the energy derived from its food. Accordingly, upon hatching, in the Holometabola, a feeding period or instar comes first, followed by a molt and growth. At this point the story of the metamorphosis differs from that of the Hemimetabola, for after the molt no change in appearance to make the young insect more nearly like the adult takes place. It may be different in some regards, besides size, from what it was before the molt, but these differences do not increase its resemblance to what it finally becomes. This holds throughout the feeding period of its existence, so that after three, four or more molts a caterpillar is still a caterpillar, a grub is still a grub, and this is equally true for all Holometabolous insects.

Within the insect during this period, however, changes not perceptible on the surface are taking place, by the construction of portions of the adult which are forming as buds or ingrowths from various parts of the body and are termed imaginal buds (from "imago," the adult). They are closely compacted and many at least are infolded somewhat like buds, becoming finally ready to open when the proper time comes. And during its feeding instars, the larva is storing energy from its food not only for its growth at each molt but also to carry it on through a period yet to be described, during which it must transform into the adult condition while unable to feed and obtain the energy needed for this purpose (Fig. 32D). After a varying number of feeding instars and molts, the young insect or larva has grown sufficiently and has stored within it energy enough to carry it through the remainder of its changes, and internally the essential parts for the adult condition have been formed as far as possible under existing conditions. As the next change will produce an animal practically helpless in most cases, and unable to protect itself from its enemies, its next step is to find as much protection as possible.

Accordingly, the full-grown larva usually, though not always, leaves the place where it has been feeding and elsewhere prepares for its next change. Many larvae begin this by spinning around themselves a thread of silk, produced by glands within the body and opening to the surface on the lower lip. This thread is spun backward and forward and around the body until it sometimes forms a complete outer covering, entirely concealing the larva within from view. This case or cocoon appears to be protective in its function (Fig. 32D). Some larvae go underground for this change. Here a cocoon, as such, seems unnecessary; but after digging into the earth a few inches, the insect forms a little earthen chamber or cell in which to lie and generally lines this more or less densely with silk, probably to keep the earthen walls from falling in and crushing it. A larva transforming in tunnels in wood where it has fed may make a partial cocoon with more or less of the chewed-wood fragments mixed in. One staying above ground but not in tunnels or otherwise protected will spin more or less of a cocoon as already described. The completeness of the cocoon, however, varies greatly with different insects.

Instead of being a thick, dense wrapping which entirely conceals the insect, it may be so scanty that the animal within can be seen to some extent. In other cases it is merely a sort of network, in no degree giving concealment; and in still others, a few scattered threads to hold the insect in place are all that represent it. Sometimes hairs from the body of the larva, held together by silk, form most of the cocoon, and in the case of butterflies only threads enough to attach the hinder end of the body at the place where it is to transform, and to form a supporting loop around its middle, the ends of the loop also being fastened to what it rests on, are produced. In some flies the larva shrinks within its larval skin and transforms, this skin, now called a puparium, functioning like a cocoon (see Fig. 34c). The reason for such variations in a structure, presumably formed for the purpose of protection, can only be guessed at. Possibly in the course of generations some insects found less need of this than others and gradually reduced it, thereby saving the vital energy so much needed for transformation, which would otherwise be expended in cocoon making.

Whether the larva forms a dense or scanty cocoon, or none whatever, the next step in the process is a molt. When the insect escapes from this skin, however, a great change in its appearance is evident, and it is now called a pupa (Fig. 34a and b). In a general way it may be said that it has at this one molt changed more than halfway to its adult condition. This is due in part at least to the unfolding of the imaginal buds already referred to, which contribute largely to form the new surface of the body in which head, thorax and abdomen are evident, as are also the antennae, legs, stubs of wings and other adult structures. Many of the internal organs of the larva, though, were necessary for use till the last moment before it became a pupa. Then, too, the arrangement of the muscles in the larva would not be that needed by the adult. Accordingly, most of the internal organs now gradually break down, losing all their earlier form and structure, and new ones to meet the needs of the adult are constructed to take their place.

During this breaking down and the reconstruction period, the pupa is practically helpless in most cases; hence generally the need for the protecting cocoon or earthen cell it constructs. When the structure of the adult insect has been completed, another molt takes place, the pupa skin splitting and setting free the insect. If it was enclosed in a cocoon, it now produces a fluid which sufficiently softens the silken threads so that it can push its way out and it escapes or "emerges." It is now soft, its wings are only partly expanded, as in most cases there would be no room for full-sized wings in a pupa, and because of its reconstruction there is considerable waste matter in its body. The insect crawls upon whatever it may find to hold on to, expels the waste matter, and its wings begin to grow rapidly. Drying out also takes place and in a short time (a few hours) the adult thus produced is in every way fully matured. In some cases maturity of the reproductive organs is not complete until a little later.

To summarize the differences in metamorphosis of the three groups it may be said that in the Ametabola the insect hatches from the egg practically in an adult condition; i.e., there is little or no metamorphosis. In the Hemimetabola the insect hatches from the egg in a form somewhat resembling the adult but much smaller. It becomes adult by alternating periods of feeding with molts, at which times growth and changes bringing it nearer to the adult occur, the last molt completing the growth and adult structure. In this life history we have a change; but as there was a resemblance to the adult from the start, the change to it (metamorphosis) is only an incomplete or partial one. In the Holometabola the insect hatches from the egg in a form totally unlike the adult, and, while feeding periods followed by molts and growth give increase in size, no external evidence of any changes making the insect more like the adult can be found. These changes are largely made after the end of the feeding and growing periods during a pupa (generally quiet) stage, in which the breaking down of the larval, and construction of the adult, structures is completed.

The difference between the larva on hatching and the adult is so great that an entire change (complete metamorphosis) takes place. It should be evident from the foregoing that, when the adult condition is once reached, little if any growth is possible (except in rare cases) and that the belief so common that "big flies grow from little flies" is without any basis of fact. The nymphs of the Hemimetabola appear not to have attracted sufficient attention to have received any special common names. In the Holometabola the larvae of various groups differ greatly in appearance; many are large and noticeable and some of them have, as a result, received special names. Larvae of butterflies and moths are commonly called caterpillars; those of beetles are usually called grubs; those of flies are called maggots. Larvae found boring in wood, however, whether they will become moths, beetles or other insects, are uniformly called borers. In the Hemimetabola, then, the stages of life are egg, nymph, adult; in the Holometabola they are egg, larva, pupa, adult. Whether or not the pupa is enclosed by a cocoon depends upon circumstances.

South Dakota Ecological Services Field Office: American Burying Beetle Photo by Doug Backlund ( FAMILY: Silphidae DESCRIPTION: The American burying beetle is a large black insect with two distinct orange bands on each elytra (wing covers). The pronotum (shield-like structure behind the head) is orange with a black border. Each antennae is tipped with orange and there is an orange patch on the head. This large beetle is about 1.5 inches long. STATUS: The American burying beetle was listed as an endangered species in 1989 (Federal Register 54:29652-29655). REASON FOR CURRENT STATUS: Populations of American burying beetles have been extirpated from 90% of their original range. In the 1980s, entomologists documented the decreasing abundance of the American burying beetle across its range. Collecting records indicate that east of the Appalachian Mountains the American burying beetle declined in a generally north to south direction, and the decline was well underway, if not complete, by 1923. West of the Appalachians, the decline occurred later.

In the Midwest, the decline appears to have proceeded generally from the center of the range outward, with all collections since 1960 occurring at the western and eastern peripheries of the range. REPRODUCTION AND DEVELOPMENT: Adults become active in early summer. These carrion beetles lay their eggs in the carcass of small animals. A male and female pair locate a carcass of appropriate size using olfactory (smell) organs located in their antennae. The carcass is moved to a substrate soft enough to bury the corpse. The pair work to remove soil from beneath the carcass until it settles into a shallow grave several inches below the ground surface. After removing feathers or fur, the beetles secrete a substance that slows the decomposition of the carrion. The corpse is then buried but the female creates a small chamber above the carcass where she lays from 10 to 30 eggs. The larvae receive parental care during the entire time they are feeding and growing. This is an extremely rare behavior in insects, a condition normally found only in the social bees, wasps, ants and termites. Both adults regurgitate food to begging larvae. The larvae grow rapidly and are soon able to feed themselves.

The adults continually tend the carcass, removing fungi and covering the carrion ball with an antibacterial secretion. Sometimes the size of the brood is too large to be successfully reared on a small carcass, and both adults will cannibalize small larvae. After about a week, the larvae have consumed all but the bones of the carcass, and the adults fly away. Adults live only one season. The young pupate in the nearby soil and emerge as adults about a month later. Beetles overwinter in the adult stage. Of principal importance to the beetles and their young is burial of the food resource, which effectively removes it from intense competition by maggots, other carrion-feeding insects and even mammal scavengers. RANGE: The American burying beetle has been recorded historically from at least 150 counties in 35 states in the eastern and central United States, as well as along the southern fringes of Ontario, Quebec and Nova Scotia in Canada. The American burying beetle has been found in Nebraska, Rhode Island, Oklahoma, Arkansas, South Dakota and Kansas. Reintroductions are ongoing on Nantucket Island, MA; Wah' Kon-Tah Prairie, MO; and in Ohio.

In South Dakota the heart of the population is found in southern Tripp County. Some individuals are found in eastern Todd County and western Gregroy County. One specimen was found along the South Dakota/Nebraska border in Bennett County. POPULATION LEVEL: A South Dakota population estimate was conducted in 2005. an estimated 1,000 individuals reside over 500 square miles of occupied habitat. The nearby Nebraska population occupies a large geographic area of the Sand Hills. HABITAT: Considering the broad geographic range formerly occupied by the American burying beetle, it is unlikely that vegetation or soil type were historically limiting. Today, the American burying beetle seems to be largely restricted to areas most undisturbed by human influence. Carrion availability (appropriate in size as well as numbers) may be the more important factor of where beetles occur than the type of vegetation or soil structure. Habitats in Nebraska where these beetles have been recently found consist of grassland prairie, forest edge and scrubland. Specific habitat requirements are unknown. MANAGEMENT CONSIDERATIONS: The cause for the decline of the species is complex and difficult.

However, in order to implement an effective recovery program and to locate additional populations, it is necessary to understand the possible factors influencing the decline. The decline of the American burying beetle is probably the result of an interplay of several complex factors that include (1) artificial lighting that decreases populations of insects active at night, (2) changing sources of carrion because of habitat alteration, (3) isolation of preferred habitat because of land use changes, (4) increased edge effect harboring more vertebrate competitors for carrion and (5) the possibility of reduced reproduction because of some genetic characteristic of the species. Fragmentation of large expanses of natural habitat changed the species composition and lowered the reproductive success of prey species required by the American burying beetle for optimum reproduction. Fragmentation also resulted in an increase in edge habitat that supported and increased the occurrence and density of vertebrate predators and scavengers such as crows, raccoons, foxes, opossums and skunks, all of which compete with the burying beetle for available carrion.

Fragmented habitats not only support fewer or lower densities of indigenous species that historically may have supported burying beetle populations, but there is also now a great deal more competition for those limited resources among the "new" predator/scavenger community. The U.S. Fish and Wildlife Service, in cooperation with the scientific community, has formulated a recovery plan that is now being implemented. Surveys at several places in the eastern United States are being conducted to find remnant populations so they can be protected from land development authorized or funded by state and federal agencies. The search for remnant populations is now the primary activity in Nebraska. The populations in Rhode Island, Arkansas and Oklahoma are being monitored, and the habitats there are being managed to prevent any disruption that might be harmful. Beetles are being reintroduced in Massachusetts from a laboratory colony at Boston University, and other introductions are planned. Life history studies are being conducted in order to determine possible factors responsible for the decline of the species. Similarly, DNA studies are ongoing to ascertain what, if any, genetic differences exist among the known populations. Knowledge of those differences could be important for future breeding programs. Finally, a public education program has been developed to increase awareness of the importance of this unique insect.

Additional information available online: Cockroaches : University of Minnesota Extension University of Minnesota Extension Cockroaches Jeff Hahn and Mark E. Ascerno There are four kinds of cockroaches that can infest homes in Minnesota, including German cockroach, brownbanded cockroach, American cockroach, and Oriental cockroach. These four species can be major pests in restaurants, hospitals, warehouses, offices and buildings with food-handling areas. A fifth kind, the Pennsylvania wood cockroach, may enter buildings accidentally but become only a temporary nuisance. University of Nebraska Fig. 5. Pennsylvania wood cockroach University of Nebraska Fig. 7. Cockroach egg cases Fig. 8. Sticky roach trap under kitchen sink Importance Many people are repulsed and/or disgusted by the simple presence of cockroaches. However, they are also an important public health problem by contaminating food and eating utensils. Cockroaches are known to carry human pathogens, such as Salmonella and E. coli, which can result in human diseases, such as food poisoning or diarrhea. Occasionally, they will destroy fabric and paper products. In large numbers, cockroaches secrete a substance which can result in stains on surfaces they contact and produce disagreeable odors.

Finally, products of cockroach infestations, including saliva, feces and cast skins, are a source of allergens and can irritate allergies and asthma in people, especially children. Identification Correct identification of suspected cockroaches is important as there are many insects that look similar (e.g. long-horned beetles, crickets, leaf-footed bugs and ground beetles). A cockroach has a flattened, oval shaped body and long antennae (about the length of their body). When looking at a cockroach from above, its head is hidden from view. It has six strong legs covered with spines (figs.1, 2, 3, 4, 5, 6). Many adult cockroaches have fully developed wings, although few fly. Other cockroaches have short wings or lack wings altogether. Young, immature cockroaches resemble adults but are smaller and wingless. If there is any doubt about whether an insect is a cockroach, submit a sample to an insect specialist or a pest management expert. Biology A cockroach has three stages during its life cycle: egg, nymph, and adult.

Adults lay eggs contained within egg cases that are dark-colored and roughly the same size and shape as a dry kidney bean (fig. 7). Depending on the species, an egg case contains between 16 - 50 eggs. Eggs hatch into young cockroaches called nymphs. In a normal cockroach population, nymphs are more numerous than adults. Cockroaches are nocturnal, hiding during the day and becoming active at night. The number of cockroaches people see is usually a small percentage of a much larger population. Cockroaches prefer different habitats depending on the species. German cockroaches prefer dark, warm, humid areas near sources of food and water. American and Oriental cockroaches prefer coolers areas, such as basements and crawl spaces. Brownbanded cockroaches prefer drier areas, such as pantries and closets. All cockroaches are scavengers and will survive on almost any food as well as backing glue, leather, bookbindings, bar soap. They may even sample electronics and wiring in television and microwave (though infestation have to be large when this type of damage occurs). They spend most of their time in narrow, tight cracks and spaces where surfaces touch them on both sides.

Cockroaches tend to congregate in corners and generally travel along the edges of walls or other surfaces. Types of cockroaches The German cockroach is the most common indoor cockroach species in Minnesota. It favors warm, humid atmospheres, especially areas where temperatures are around 70° to 75° F. It generally inhabits kitchens and bathrooms where they are found near plumbing fixtures, in cracks or crevices in cupboards, under drawers and kitchen sinks, and similar locations. These cockroaches often cluster together in favorable hiding areas. When severe infestations occur, they may be found in other sections of buildings. German cockroaches can disperse in large numbers from areas of high population densities to infest other locations. The adult (fig. 1) is about ½ inch long, light brown or tan, and has two dark longitudinal bands or streaks on the prothorax behind the head. This species has the highest reproductive potential of all the common pest cockroaches. Females produce about 30 to 50 eggs at a time. The female carries the egg case until the eggs are ready to hatch. The immature nymph (fig.

1) is smaller, dark-colored with a light-colored streak running down its back. An immature nymph reaches maturity in about 40 to 125 days. Adult females live about 200 days, producing six to eight egg cases throughout their life. The brownbanded cockroach may also be common in Minnesota homes. Individuals can be widely distributed throughout a building, particularly in high areas, hiding behind pictures and clocks, beneath furniture, among books and in other drier areas not normally infested by German cockroaches. They seek areas that are warm most of the time including appliances such as radios, televisions and refrigerators. The brownbanded cockroach prefers warmer temperatures (greater than 80° F) than the German cockroach. The two species are rarely found together. The adult brownbanded cockroach is about ½ inch long. An adult male is golden brown and has a narrow body with its wings extending beyond the tip of its abdomen (fig. 2). A female adult is dark chestnut brown, has a teardrop-shaped body, and its wings do not completely cover the abdomen (fig. 2). Both sexes have distinctive horizontal yellow bands.

The female often glues its egg case on furniture or in appliances. Eggs take about 70 days to hatch and about 160 days for the young to reach maturity. A nymph is recognized from the two pale bands which run horizontally across its body. The Oriental cockroach prefers dark, damp places. Often called a water bug, it is commonly found in damp basements, cellars, crawl spaces, and sewers. It may also be found near drains, leaky water pipes and under refrigerators, sinks, washing machines, and floors. It prefers temperatures under 84° F. The Oriental cockroach can tolerate cool environments and people have even found it surviving freezing outdoor weather. An Oriental cockroach forages mostly on the first floors of buildings. Occasionally, this pest will thrive in the landscape immediately adjacent to structures and may enter if a disturbance occurs, such as a change in the seasons, excess rainfall, or lawn mowing. It can be found occasionally outdoors under sewer covers. It feeds on all types of garbage and other organic material. An Oriental cockroach produces a strong smell and is considered one of the dirtiest of all the cockroaches.

An adult Oriental cockroach is about 1 to 1-1/4 inches long and dark brown, almost black. A male has fully developed wings which are shorter than the body. A female has very short, rudimentary wings (fig. 3). A nymph is similar in appearance to a female only it is smaller and wingless. A female deposits an average of eight egg cases during its lifetime; each capsule produces about 16 young. It takes 300 to 800 days, depending on conditions, for Oriental cockroaches to hatch from eggs and develop into adults. The American cockroach is occasionally found in homes, although it is more common in restaurants, grocery stores, and bakeries and other sites where food is prepared. It favors very warm, moist places (temperatures in excess of 82° F). An American cockroach has a fondness for fermenting foods, e.g. bread soaked with beer. Their foraging is confined mostly to the basement and ground floor of a building unless suitable conditions exist in higher locations. Sewers and drain lines may help this pest invade new areas. This is the largest cockroach species to infest buildings in Minnesota.

Both the adult male and female is about 1-1/2 to 2 inches long, reddish brown and possesses long wings that cover its abdomen (fig. 4). A female typically produces 9 to 10 egg cases which are deposited carefully in a crack or crevice. Eggs hatch in about 45 days with each case producing about 14 young. An immature nymph is reddish brown and wingless. A young nymph matures in as little as 215 days to as long as 400 days. The average life span for adult females is about 440 days. The Pennsylvania wood cockroach lives in wooded areas in rotting logs and under loose bark. It can accidentally invade homes, cabins, cottages, and other buildings in or near wooded areas. This cockroach is not a persistent household pest and it doesn’t reproduce indoors. Because of its association with wood, a Pennsylvania wood cockroach can be brought indoors on firewood. It may enter buildings if suitable harborage (trees and logs) is close to open doors and windows. The males are strong fliers.

The adult male is one inch long, dark brown, with light-colored bands on the edge of the body near the head (fig. 5). Males also have long, well-developed wings. The adult female is similar, but with very short wings (fig. 5), measuring about 1/2 inch long. Adult females and immature nymphs can be confused with the Oriental cockroach. However, the Oriental cockroach lacks the light bands on the edge of its body near the head. If there is any doubt, submit a sample to an insect specialist or a pest management expert for identification. Manage Pennsylvania wood cockroaches by reducing their breeding places. Remove decayed and fallen logs within a few hundred feet of a building. Physically remove an occasional Pennsylvania wood cockroach that you find indoors. If larger numbers are entering the home, you may wish to treat the exterior of the building, particularly around doors and windows, with a residual insecticide. Common products include permethrin, bifenthrin, or cyfluthrin. Australian cockroaches (fig. 6), Surinam cockroaches, and Madeira cockroaches are examples of subtropical cockroaches that are rarely seen in Minnesota.

When they are found, it is because they have been accidentally transported into the state. These insects are not accustomed to Minnesota conditions—it is too cool and dry for them to establish themselves indoors. However, these cockroaches can survive if they are accidentally introduced into a greenhouse or other location where there is sufficient warmth and humidity. Australian cockroaches will infest similar areas that the American cockroach will inhabit. The Surinam and Madeira cockroaches can sometimes be found in potted plants associated with contracted indoor landscaping and indoor arboretums. If there is any question whether you have encountered such a cockroach, submit a sample for identification to an insect specialist or a pest management expert. Management Preventive measures Cockroaches can be carried into homes in bags, boxes, and luggage. Corrugated cardboard boxes are a particularly good source of infestations. Examine containers that are brought into your home carefully for the presence of cockroaches or their egg capsules, especially if they are brought in from locations known to be infested with cockroaches. If you suspect cockroaches may have been brought into your home, set out sticky traps to monitor their presence. Place sticky traps so they are tight against edges, e.g.

where walls meet floors (fig. 8). Place them in areas where cockroaches are likely to occur, e.g. in cupboards and around refrigerators, stoves, and sinks. Sanitation Sanitation is very important to reduce cockroach infestations. Cockroaches need water and food to live. By limiting their access to these resources, you reduce their ability to survive and reproduce. It is difficult to make your home and other buildings completely unacceptable for cockroaches, but you can minimize an existing infestation when improving sanitation. Do not leave food out over night; keep all food stored in a refrigerator or in insect-proof containers made of plastic, metal, or glass with tight-fitting covers. Do not leave pet food and water out overnight. Wash your dishes, pans, and utensils as soon as you are done using them. Remove all food or spilled drinks from counter tops and clean counters, sinks, and tables with soapy water. Vacuum all cracks and crevices to remove debris and food. Also sweep or vacuum any food and debris on floors. Take garbage out daily in closed plastic containers; keep waste containers washed and clean. Repair any leaky water pipes or faucets.

Recycle cans and bottles on a regular basis; wash and clean containers that hold recycling items. Increase ventilation where condensation is a problem. Harborage reduction Cockroaches also need favorable places to live to successfully live and reproduce. You can reduce cockroach numbers when you eliminate favorable sites. Remove boxes, especially if they’re made from corrugated cardboard, newspapers, bags, and other unnecessary items that can clutter rooms. When storing items, leave space between the packages. Use caulk to seal spaces and cracks where cockroaches hide. When an infestation exists in a home, concentrate on areas where cockroach numbers are the highest. Seal spaces, e.g. with steel wool, in apartments and other multi-unit dwellings where plumbing or electrical wiring goes through walls. Placing escutcheon plates at points where plumbing enters the wall will help prevent cockroaches moving to other areas in multi-unit dwellings. Non-chemical management Physical removal. Vacuuming can remove a significant number of cockroaches and egg cases from the environment and can be quite effective when combined with other methods. When possible, use vacuums with a high efficiency particulate air (HEPA) filter to reduce cockroach debris that may become airborne.

Sticky traps help capture cockroaches but generally do not capture enough insects to be practical to help reduce a cockroach problem. However, they are a useful management tool to monitor for the presence of cockroaches. Cold Treatment. You can cold treat small items, such as toasters, clocks, or boxes, to kill cockroaches that may be infesting them. Put the item in a plastic bag, close it up, and put the bag in a freezer. In winter, you could set the bag outside when temperatures are at or near 0 degrees F. Leave the bag in the cold for 5 days. After that, clean the item well before bringing it back into your home. Insecticidal control If you have a cockroach problem, it is often necessary to apply an insecticide in addition to nonchemical measures to eliminate an infestation. Insecticides, however, are much more effective when their use is combined with sanitation, harborage reduction, and other nonchemical efforts. It is often very challenging to treat cockroaches. In most cases, it is best to hired an experienced pest management service (pest control company) to treat them. They have the necessary experience and tools to successfully eliminate these pests from your home.

However, your cooperation with a technician in improving sanitation and reducing harborage areas is very important in the management of cockroaches. If you attempt to treat a cockroach problem yourself, it is first important to determine where they are most common. You can do this by setting out sticky traps (purchased under such names as Roach Motel or Roach Trap). Distribute the traps in a variety of locations, especially in areas where cockroaches have been sighted. Be sure traps are placed tightly against walls or objects so cockroaches can not go around them. Remember that cockroaches prefer warm, moist areas near water sources. Record the number of cockroaches trapped and apply insecticides near the traps with the largest catches. There are several options for insecticide treatment of cockroaches, baits, dusts (powders), and sprays (liquid or aerosol). Cockroach baits are typically available in ready-to-use plastic child-proof containers. Common active ingredients include abamectin, fipronil, or hydramethylnon. Place them in areas where you find cockroaches following label directions. An advantage of baits is that they can be placed in very precise locations which avoids general broadcast applications.

However, baits act somewhat slowly and results may not be easy to see when they are first used. You can supplement baits with applications of boric acid, a type of inorganic dust. Common trade names include Roach Powder and Roach Prufe. Place boric acid in isolated places, such as behind and under refrigerators, stoves, and sinks. Do not apply boric acid where children and pets can reach it. There are many insecticide sprays available in ready-to-use aerosol or liquid products. Some common active ingredients include permethrin, deltamethrin, cyfluthrin, and cypermethrin. Spray in precise, specific sites in cracks and crevices behind sinks, cabinets, around drains and plumbing, and other sites allowed by the label. It is not necessary to treat flat surfaces such as countertops, floor surfaces, etc. Avoid contaminating food, dishes, or utensils. Caution: Read all label directions carefully before buying insecticides and again before you apply them. Always follow all label directions completely. The label is the final authority for use of the product. Do not use aerosol foggers and bombs.

These products do a poor job of delivering insecticides to the cracks and crevices where cockroaches hide while increasing the exposure of pesticides to people and pets. Cockroaches are particularly challenging to control in multi-unit dwellings, such as apartment buildings. It is usually necessary to treat the units that are known to be infesting as well as all adjacent units. Cockroach control in multiple unit buildings usually requires the services of an experienced pest management service. Moving Take preventive measures to minimize moving cockroaches with you. When possible, use boxes and packing material from a place un-infested with cockroaches. When packing, watch for cockroaches and their egg capsules (fig. 7), removing and destroying any you find. The capsules are dark-colored and about the size and shape of a dry kidney bean. Ideally, it is best to take all boxes out of the home by night time and store in place that is un-infested with cockroaches. If boxes must be stored overnight in infested buildings, keep them off the floor and away from walls by placing them on chairs or tables. During the winter, you can store boxes in unheated locations, such as garages.

Once you have arrived at your new home, again watch carefully for egg capsules and cockroaches that may have survived the trip. If you are not sure whether you brought any cockroaches with you, set out sticky traps to determine if they are present. It is much easier to deal with a small population of cockroaches right away than to allow them to become abundant and then try to treat them. Related information

Question: What part of the body does an insect finally have to grow to become an imago?
Answer: Wings