Glossary

abdomen: The posterior section of the three sections (head-thorax-abdomen) of an insect's body. The abdomen contains the reproductive and excretory organs, and the bulk of the digestive system. The abdomen bears no functional legs in the adult stage.
acaricide: A pesticide used specifically to manage or prevent damage caused by mites. Sometimes generalized to be synonymous with pesticides.
active ingredient: The chemical or chemicals in a pesticide responsible for killing, poisoning, or repelling the pest. Listed separately in the ingredients statement.
aerosol: A material stored in a container under pressure. Fine droplets are produced when the material dissolved in a liquid carrier is released into the air from the pressurized container.
ants: (Formicidae): A family of insects related to bees and wasps.

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antenna (pl., antennae): The paired segmented sensory organs, borne one on each side of the head.
aphids: (Aphididae): A family of insects related to whiteflies and planthoppers. Aphids are soft-bodied, sometimes called plant lice, and feed by sucking juices of plants. See aphids.
arthropoda: That branch (phylum) of the animal kingdom whose members have jointed legs and are also made up of rings or segments. For example, worms, insects, crustaceans, etc.
attractant: Something that is attractive. For example: the song of mole cricket males is attractive to females of the same species, and also is attractive to the gravid female fly Ormia depleta. Songs of mole cricket males also attracts some other males of the same species and, to an even more limited extent, of other species. Incandescent and fluorescent lights are attractive to some flying adult mole crickets at night and to some other insects. Traps have been designed to take advantage of these attractants. Baits have been developed as attractants for mole cricket nymphs and adults. In some insects, the scent of females is attractive to males and/or the scent of males is attractive to females, but this kind of attraction has not been demonstrated in mole crickets.

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augmentative biological control: The release of additional numbers of a natural enemy when too few are present to control a pest effectively. This relies on an ability to mass-produce large numbers of the natural enemy in a laboratory. For instance, there are native species of predatory mites which attack and kill pest mites on strawberries and other crops. Growers can buy large numbers of these predatory mites to augment those already on their crops, and so achieve biological control of the pest mites.
bacterium (pl., bacteria): Minute living organisms which are neither animals nor plants. There are large numbers of species. Some bacteria are entomopathogens.
bait: A food or other substance used to attract a pest to a pesticide or trap.
bees: (Apoidea): A superfamily of insects related to ants and wasps. While there are several familes of bees, it is the carpenter, bumble and honey bees that are most commonly known. Many of the other familes of bees are solitary.

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beetles: Any species in the order of insects called Coleoptera that has four wings of which the outer pair are modified into stiff covers (elytra) that protect the inner pair when at rest.
biological control: The use of natural enemies to control pests. Forms of biological control include: Classical Biological Control, Biological Control by Habitat Manipulation, Augmentative Biological Control, and use of Biopesticides. Contrast with Natural Regulation.
biological control by habitat manipulation: A method of promoting populations of natural enemies by making conditions more favorable for it. For example, Larra bicolor (a wasp parasitoid of mole crickets) adults require nectar as an energy source, and obtains nectar only from a small number of plant species. The deliberate planting of such plants is biological control by habitat manipulation.
biopesticide: (Also called biorationals) Pesticides composed of very large numbers of a biological control agent, generally a pathogen. For example, Bacillus thuringiensis (often called B.t. for short) is an bacterium that kills insects and can be produced on an industrial scale. When sprayed (much like a chemical) this pathogen kills insects and does not persist long in the environment. Its advantage over many chemicals is that it is not toxic to birds, mammals and fish. The fact that it is not a specialist natural enemy allows commercial companies to sell it for use against various pest insects and thus obtain a large market for the product. The disadvantage is that it may kill non-target insects in the same family as the pest, or even of many other insect families which are more distantly related. See Economics of Biological Control.

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borers: The name given to immature stages of beetles and moths that live and feed inside plants by boring through the living tissue. See borers.
bugs: In the entomological sense many families of 4-winged insects (including tens of thousands of species worldwide) in the order Hempitera in which the second pair of wings is used for flying. The first pair is partially toughened, partially membranous, and helps to protect the second pair.
capsule: Sometimes used to describe an egg case, as in the othecae.
caterpillar: The larva of butterflies and moths.
caudal: Posterior, occuring at or towards the tail of the insect.
cerci: Appendages of the tenth abdominal segment, usually slender, filamentous, and segmented.
chilopoda: This class consists of the centipedes which are elongate, flattened animals with 15 or more pairs of legs. Each segment contains a single pair of legs.
chlorinated hydrocarbon: A group of pesticides that contain chlorine, carbon, and hydrogen.
class: Part of the system of biological classification. Insects, mammals, nematodes, millipedes, centipedes, etc. each have their own classes. A class is below a phylum, but above an order.

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classical biological control: The introduction of specialist natural enemies from the homeland of a pest of foreign origin. The objective is to establish populations of these natural enemies to attack the pest and to reduce its numbers. Sometimes quite small numbers of the natural enemy succeed in establishing a population when they are released. See Economics of Biological Control.
commensal: A term used to describe animals that habitually eat together.
contact pesticide: A pesticide that causes death or injury to insects when it contacts them. It does not have to be ingested. Often used in reference to a spray applied directly to a pest.
cornicle: Tubular structures placed posteriorly on each side of the abdomen of aphids from which various alarm pheromones are released.
crawler: This is the term used to describe the active first instar in a few families of whiteflies and scales. This instar moves to find a suitable feeding site and then embeds its piercing-sucking mouthparts into a plant. Later instars usually do not move from this site so the term crawler is is often used in place of "first instar."

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crustacea: Most species in this group (Class Crustacea) are marine or fresh water animals, although there are a few terrestrial species. While the familiar larger types, lobsters, crayfish, crabs and shrimp, are in this group, it also contains many small to minute aquatic forms that are very important in aquatic food chains.
diplopoda: This class consists of the millipedes which are elongate, wormlike animals with many pairs of legs. Most millipedes have 30 or more pairs of legs and most body segments bear two pairs.
dorsal: The upper part of a given area.
dust: A finely ground, dry pesticide formulation containing a small amount of active ingredient and a large amount of inert carrier or diluent such as clay or talc.

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economics of biological control: Classical biological control typically is performed by personnel of university and federal and state departments of agriculture. Once a classical biological control agent is imported and populations of it are established, the benefits of its actions are free; the natural enemy is not for sale, nor is there any point in selling it. In contrast, although basic research toward the use of a biopesticide may be performed by university personnel, the later development is performed by commercial companies which expect to profit by repeated sales. Therefore, classical biological control depends only upon funds for research and dissemination, and may yield an extremely good cost-benefit ratio. Biopesticides are marketable products which recoup their developmental costs through sales, and may not be less expensive than chemical pesticides.
economic threshold: Levels of pest populations at which damage from pests is considered more expensive than pest control. In an urban setting, this is complicated by the fact that a single visible insect in a residence or business can be considered offensive.

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ectoparasitic: A parasite that lives on the outside of its host.
entomologist: A person who studies insects. Nowadays, entomology is such a large subject that entomologists specialize in some aspect of it. They may work only on identification of some group of insects, or on biochemistry or genetics of insects, or on control of insects in a small range of crops, or on mathematical modelling of insect populations.
entomopathogen: An organism (generally a bacterium, virus, protozoan or fungus) causing disease in insects.
family: Part of the system of biological classification: a group of closely-related genera. All whiteflies belong to the family Aleyrodidae. The name of a family of animals (e.g., Aleyrodidae) always has a capital initial letter and always ends in -idae. The family name is not placed in italics or underlined.

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flies: Many families of 2-winged insects in the order Diptera (including tens of thousands of species worldwide). Dragonflies, butterflies, and whiteflies are not flies in the entomological sense, but house flies, horse flies, lovebugs, sand flies, and tachinid flies are.
fontanelle: A pore on the frontal region of the head of some termites through which secretions of the frontal gland are exuded.
formulation: The pesticide product as purchased, containing a mixture of one or more active ingredients, carriers (inert ingredients), and other additives making it easy to store, dilute, and apply.
frass: Solid larval insect excrement or plant fragments made by wood boring insects, usually mixed with excrement.
fungicide: A pesticide used specifically to manage or prevent damage caused by a fungus. Sometimes generalized to be synonymous with pesticides.
fungus (pl., fungi): Living organisms which are neither animals nor plants. There are large numbers of species. Mushrooms and molds are fungi. Some fungi are entomopathogens.

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gallery: The horizontal tunnel dug just below the soil surface by a soil insect, i.e. a mole cricket nymph or adult. Termites also build galleries in wood by feeding on the cellulose. Carpenter ants often use termite galleries that have been abandoned.
generalist natural enemy: A natural enemy with a broad range of diet. Cattle egrets, for example, eat many kinds of insects, and are not specialized natural enemies of any of them. Generalist enemies are not used nowadays in classical biological control though some such uses did occur, especially in the 19th century, before biological control became a profession. Generalist natural enemies may, however, be purchased commercially and released to provide biological control of some pests.
genus (pl., genera): Part of the system of biological classification: a group of closely-related species. The word is singular (a genus), and its plural is genera (two genera). The genus name usually is placed in italics or is underlined, and it has a capital initial letter. Example: Periplaneta americana, the "Periplaneta" is the genus name.
gnat: A term commonly applied to small flying insects, especially flies (order Diptera) or true bugs (order Hemiptera). Some fly and bug families include the term "gnat" in their approved common name.
growth regulator: A pesticide constructed to mimic insect hormones that control molting and the development of some insect systems affecting the change from immature to adult. In most cases this pesticide prevents the insect from becoming a sexually mature adult, and perhaps even causes its death.
grub: A legless insect larva.

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harborage site: Small cracks or areas where insects or other pests remain safely hidden during their periods of rest. Harborage sites are usually located near food and water sources.
herbicide: A material used specifically to manage or prevent damage caused by weeds. Sometimes generalized to be synonymous with pesticides.
honeydew: A mixture of sugars and other plant-derived chemicals excreted by some species of aphids and by some species of insects in families related to aphids. When these insects feed on plants, honeydew drips from them onto plant leaves or onto the ground. Fresh honeydew may be fed upon by other insects as an energy source. Ants of many species are avid feeders on honeydew, and they may even guard the aphids against predators and parasitoids to protect this energy source. Unconsumed honeydew on plant leaves promotes growth of a black fungus called sooty mold, which may become so dense that it interferes with the metabolism of the plant.
host: An organism (animal or plant) fed upon by a parasite or parasitoid. When insects or nematodes feed upon plants they are considered parasites of those plants, and the plants are then referred to as host plants.
host plant resistance: Host plant resistance is one of the preferred methods for minimizing the damage caused by pests and and associated viruses, because it does not require the complete elimination of the pest to be effective. HPR protects the crop by making it less suitable for the pest or by making the crop tolerant to the pest. The result is less crop damage. An example of this is the use of hairy-leaf cotton rather than smooth-leaf (glabrous) cotton to reduce the impact of whiteflies on yield.
hyperparasitoid: A parasite that lives on or in another parasite.

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insect: The class of small animals with three pairs of jointed legs and one pair of antennae, at least in the adult phase. Mole crickets, tachinid flies, and sphecid wasps all have this arrangement in the adult phase, and mole cricket nymphs also have it. However, some insect larvae (grubs) are legless. Spiders and ticks have four pairs of jointed legs, centipedes and millipedes have many more pairs, and these are not insects.
insect life cycle: There are two basic kinds of life cycles in insects. Some (for example grasshoppers) have three phases: egg-nymph-adult. Others (for example wasps and flies) have four phases: egg-larva-pupa-adult.
insecticide: A material used specifically to manage or prevent damage caused by insects. Sometimes generalized to be synonymous with pesticides.
instar: The period or stage between molts, numbered to designate the various periods; e.g. the first instar is the stage between the egg and first molt.
integrated pest management (IPM): A planned pest control program in which several methods are integrated and used to keep pests from causing economic, health-related, or aesthetic injury. Pesticide application is not the primary method of control, but is one of several elements that also include cultural, mechanical, and even structural alterations. IPM includes all practices that help to prevent, suppress, or eliminate pests to a tolerable or economic level. IPM programs stress communication, monitoring, inspections, and evaluation (keeping and using records).

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lace bugs: A large group of small insects (less then 5 mm in length) that have an elaborately sculptured dorsal surface as adults. The immatures are usually spiny. These bugs are plant feeders and their feeding causes a yellow spotting of the leaf. Some do considerable damage to trees. See lace bugs.
lacewings: There are several familes of lacewings. The adults have large wings with many veins, giving this group its name. The immatures are predaceous on many pest species and as such are important generalist natural enemies. The larvae of some species are called antlions and trashbugs.
larva (pl., larvae): One of the phases in the life cycle of some insects, such as butterflies, wasps, and flies. Larva is the singular form of the word, and larvae is the plural form. A young insect which quits the egg in an early stage of development and differs fundamentally in form from the adult; e.g., a maggot is the larval form of a fly. Many insect larvae are very different in appearance from the adults. Insect larvae do not have wings. Insect larvae feed, grow, and molt several times.
leafminers: Several very different insects can be leafminers: flies, beetles, or moths. In all cases it is the immature that bores through the leaf usually leaving a noticable trail. One beetle is a very serious pest of black locust, while one small moth is a serious pest of citrus. See leafminers.
lenticle: A pore in the stems of woody plants through which gases are exchanged.
lepidopterous: Belonging to the insect order Lepidoptera. This order contains the butterflies and moths.
maggot: The legless larva of a fly.
mandible: The first pair of jaws in insects. These are stout and jawlike in chewing insects, or needle- or sword-shaped in piercing-sucking insects
mealybugs: These insects of the family Pseudococcidae are plant feeders. The name is derived from the mealy or waxy secretions that covers the bodies of these insects. Some are important plant pests.
mesothorax: The second or middle segment of the thorax; it bears the middle legs and the front wings (if present).
metamorphosis: The series of changes through which an insect passes its growth from the egg to the larva and pupa to the adult. Not all insects have a pupal stage.
metathorax: The third segment of the thorax; it bears the hind legs and the second pair of wings (if present); sometimes hard to see as it is either closely united with the mesothorax or appears to be part of the abdomen.

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miridae: A family of abundant true bugs commonly called plant bugs or leaf bugs. These are mostly plant feeders, but some are predaceous on other insects.
mites: These arthropods are not insects, but are in the same order as ticks. They are very small and require a strong hand lens to see. Most are plant feeders and can do considerable damage. Some are important predators of other spider mites. See mites.
mole cricket (Gryllotalpidae): A family of insects related to crickets and grasshoppers. In this family the nymphs and adults are adapted for digging. There are three major developmental phases: egg-nymph-adult. There is no pupal phases. The nymphs molt six to eight times during their growth. Some of the genera included are Gryllotalpa, Nemocurtilla, and Scapteriscus.
molt: The process in which an immature insect casts its skin in order to grow. A new skin (which develops under the old skin) is a larger size.
monogyne: Having only one queen in the colony. For example, some ant species are monogyne, while others are polygyne.
monomorphic: Having only one form, or one size.
mycelium: The threadlike vegetative part of fungi.
natural enemy: (Also called a beneficial organism) A predator, parasite, parasitoid or pathogen. A natural enemy can be either a specialist or a generalist.
natural regulation: This is the action of nature without intervention by man. Populations of pests may be held in check by weather and/or by natural enemies to a greater or lesser extent. If this natural regulation did not exist, then damage to crops would be very much worse than it currently is. The worst-case scenario of total destruction of crops does not often occur, so natural regulation, a gift of nature, is worth a lot of money. The aim of biological control (an action by man) is to use whichever of the natural enemies that can be manipulated to improve on the suppressive effects provided by nature.

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nectar: A mixture of sugars and trace amounts of other chemicals produced by plants in nectaries, usually located in the flowers. Nectar is fed upon by insects as an energy source, and is used by honey bees to make honey. Contrast with honeydew.
nematicide: A pesticide used specifically to manage or prevent damage caused by nematodes. Sometimes generalized to be synonymous with pesticides.
nematoda: The nematodes comprise a class of many families of long, legless, worm-shaped animals, including tens of thousands of species worldwide. Some species are aquatic, in freshwater or the sea. Some species are parasites of birds, mammals, or other vertebrate animals. Some species are parasitoids of insects. Others feed on plant roots. Among the many families are steinernematid nematodes.
nymph: One of the phases in the life cycle of some insects, such as grasshoppers. Insect nymphs look quite similar to the adults, but are smaller and lack wings. Insect nymphs feed, and grow, and molt several times.
non-residual pesticide: A pesticide that is not effective for an extended period of time. Used to describe a contact pesticide.
ocellus (pl. ocelli): One of two (or one of three) very small, simple eyes on the top of the head of some adult insects. Adults of many species have no ocelli, but almost all adults have a pair of compound eyes.

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order: One of the primary divisions of the classification system. Consists of several to many families. An order is the major division under class.
organophosphate insecticide: A large group of pesticides that contain the element phosphorus and inhibit cholinesterase in animals.
otheca (pl. othecae): A collection of eggs enclosed in a covering of secretions that hardens to varying degrees and protects the eggs.
ovipositor: The organ that female insects use to deposit eggs. The ovipositor was formed by a prolongation or modification of the posterior abdominal segments.
parasite: An organism that lives within or on the body of its host without killing the host, but usually debilitating the host to some extent. Cat fleas are examples of parasites; note that they feed as parasites of dogs and cats during their adult phase, while in the larval stages they are not parasitic (and are not on pets). Lice, on the other hand, are parasites from the time they hatch from eggs throughout their lives. See parasitoid.
parasitoid: An organism that, during its development, lives in or on the body of a single host individual, eventually killing that individual. Larra wasps, Ormia flies, and Steinernema nematodes are examples of parasitoids; note that the wasps and flies feed like this during their larval stages, while in the adult stages they feed on nectar of plants. Many people use the word parasite when they really mean parasitoid; this is unfortunate because it obscures the lethal effect of parasitoids.

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parthenogenesis: Reproduction without fertilization by a male.
pathogen: A disease-causing organism. Many pathogens are entomopathogens.
pedicel: A stalk or stem supporting an organ or other structure, for example: the second segment of the insect antenna. In Hymenoptera (ants, bees, wasps) the one or two segments of the base of the abdomen, particularly in ants, which are much reduced.
pesticide: A substance or agent used to kill pests. Comes in many different formulations and types. There are residual, and non-residual (contact) pesticides. Pesticides are also described as insecticides, herbicides, fungicides, nematicides, and rodenticides. depending upon the class of pests they are being used to control.
petiole: The slender stem that supports the blade of a foliage leaf.
pheromone: A substance emitted by an animal to influence the behavior of other animals of the same species. Some are synthetically produced for use in insect traps.
photoperiod: The number of hours of daylight during a 24-hour period. Photoperiod is often an influential factor in animal (insect) or plant biology.
phytophagous: Feeding in or on plants.
polygyne: Having many queens in the same colony. For example, some ant species have several queens in the same colony, others tolerate only one, and are monogyne.

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polymorphic: Having more than one form, or more than one size. For example, the workers of some ant species are polymorphic.
predator: An organism that, during its development, consumes more than one prey individual. Tiger beetle larvae are examples of predators. Note that their adults, too, feed as predators.
prepupa: The active, but non-feeding, last instar larva. This stage occurs when the cuticle is separated from the hypodermis but has not yet been cast off. Occurs in thrips and female scales.
pronotum: The upper or dorsal surface of the prothorax.
prothorax: The first segment of the thorax, it bears the anterior or first pair of legs but no wings.
protozoan (pl., protozoa): A class of minute animals whose entire body consists only of a single cell. Protozoa is a plural word, the singular is protozoan. There are large numbers of species. Some protozoa are entomopathogens.

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pupa (pl., pupae): One of the phases in the life cycle of some insects, such as moths, flies, beetles, wasps and bees. It is the intermediate stage between the larva and the adult. Insect pupae do not feed.
puparium: Some fly pupae are protected by a puparium. This is the dried, hardened, cast skin of the larva
pustule: A small circumscribed elevation of the skin containing pus and having an inflamed base.
pyrethroids: These are synthetic compounds produced to duplicate or improve more or less successfully on the biological activity of the active principles of the pyrethrum plant. Pyrethrum is a natural botanical insecticide the active principles of which are extracted from the flowers of the pyrethrum plant, and are know collectively as "pyrethrins."
repellent: A compound that keeps insects, rodents, birds, or other pests away from plants, domestic animals, buildings, or other treated areas.
residual: Refers to the property of a substance (pesticides are one example) that allows it to remain in an area for an extended period.

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residual pesticide: A pesticide that continues to be effective on a treated surface or area for an extended period following application.
scales: These are flat unicellular outgrowths of the body wall in various shapes that are common to many groups of insects. Some example are: on butterflies and moths, scales are flattened plates that often contain pigments that lend color to the insect; in scale insects, scales are coverings made of waxy substances for the protection of eggs, nymphs, and adults.
scale insects: A large group of insects that are minute and highly specialized. The females are wingless and usually legless, while the males have only a single pair of wings or none at all. Adult male scales look like gnats, but can usually be recognized by the absence of mouthparts. The first immature stage is called a crawler and moves about to find a spot to feed. Later stages lose their legs and antennae (or they are greatly reduced) and lose the ability to move. These insects are one of the more destructive groups found on ornamental plants.
segment: A ring or subdivision of the body or of an appendage between areas of flexibility associated with muscle attachments.
setae: A hardened, hairlike projection surrounded at the base by a small ring.
specialist natural enemy: A natural enemy with a very restricted diet. The most specialized natural enemies are those that attack only one species (for example, the sphecid wasp Larra analis is known to attack northern mole crickets only). Others may attack several species belonging to only one genus (for example, Ormia depleta is known to attack only two members of the genus Scapteriscus [tawny and southern mole crickets]). Specialist natural enemies may be useful in classical biological control. See Generalist Natural Enemy.

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species: The basic unit of classification in biology. Examples are the bald eagle, the polar bear, the atala butterfly, and the tawny mole cricket. The word is both singular (a species) and plural (two species). Species are grouped into genera, and genera are grouped into families. The words kind, sort, type, strain, and variety are not part of this classification even though newspaper reporters often use them as if they were. The species name usually is placed in italics or is underlined. The species name does not have a capital initial letter. Example: Periplaneta americana, the "americana" is the species name.
spider mites: These arthropods are not insects, but are in the same order as ticks, both of which are in the class Arachnida. They are very small and require a strong hand lens to see. Most are plant feeders and can do considerable damage. Some are important predators of other mites. See mites.
spine: A multicellular more or less thorn-like process or outgrowth of the outer skin of an insect not separated from it by a joint.
spiracle: A breathing pore. Each segment of an insect's body has at least two spiracles on the lateral sides through which air enters the tracheae. These paired lateral openings lead from the exterior into the respiratory system of insects. The respiratory system has ducts (tracheae) throughout the body.
stage: Any definite period in the development of an insect or mite; e.g. egg stage, larval stage, etc.

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steinernematid nematode (Steinernematidae): A family of nematodes. All known species of steinernematid nematodes are entomopathogenic. They have three major developmental phases: egg, juvenile, and adult. One of the juvenile stages is capable of attacking (infecting) an insect host.
strain: A word used to label some pathogens (including insect pathogens) according to their geographical origin. For example, in the last few years a Hong Kong strain and a Beijing strain of human influenza virus have been labelled. Strains of the insect pathogen Beauveria bassiana likewise have been labelled. Strain does not mean the same thing as species.
systemic pesticide: A pesticide that causes death or injury to pests when it is injested by them during feeding. Systemic materials are applied to plants or animals and are translocated to other parts of the plants or animals than those to which the material is applied.
tachinid flies: A family of flies. In this family the adults are free-living, and larvae are parasitoids of insects. There are four developmental phases - eggs, larva, pupa, and adult. These flies do not harm people or plants.
thorax: The middle section of the three sections (head-thorax-abdomen) of an insect's body. The thorax is packed with muscles for the wings and legs which arise from that section. The thorax itself consists of three parts named in order: prothorax, mesothorax, and metathorax.
thorax: The fourth part (fourth from the body) of an insect's leg.
thrips: These are small (0.5 - 5.0 mm), slender insects with rasping-sucking mouthparts. Wings, when present, are very long, narrow and fringed with long hairs. Females are often larger then males and parthenogenesis occurs in some species. Most species feed on plants and many are serious pests of cultivated plants. A few species are predators of small arthropods. Thrips sometimes occur in large numbers and a few species may even bite people. Thrips is both singular and plural. See thrips.
tibia: The fourth part (fourth from the body) of an insect's leg.
vector: The intermediate host, of disease-producing organisms, which conveys them.
virus (pl., viruses): Simple organisms, which are neither animals nor plants, consisting of a nucleic acid (either DNA or RNA) and a protein coat (singular virus). Some viruses are entomopathogens.

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wasps: Many families of 4-winged insects (including hundreds of thousands of species worldwide) which are related to ants and bees. These families comprise the order Hymenoptera. Many wasps are smaller than a pin-head while a few are a couple of inches from wing-tip to wing-tip.
wettable powder: Another popular residual spray formulation. A wettable powder is an insecticide in which the active ingredient has been added to a fine absorptive clay. The clay is then mixed with a wetting agent in water to form a liquid spray.
whiteflies: These are very small insects, seldom more than 2 or 3 mm in length, that resemble tiny moths. The adults of both sexes are winged and are usually covered with a white dust or waxy powder. First instars are active and are called crawlers. Later instars are sessile and look like scales. They have piercing-sucking mouthparts which they use to suck sap from the leaves of plants. They also excrete large mounts of honeydew which sooty-mold grows upon. Some whitefly species are serious pests of cultivated plants. See whiteflies.

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