Intro to Entomology

Insect Pest Control

Objectives1 Define insect, and describe the biological characteristics of insects.2 Compare and contrast the types of insect life cycles.3 Compare and contrast the feeding methods of insects, and explain how insects damage plants.4 Describe methods of insect control.5 Describe the types of insecticides, and list common names for each.6 Describe the types of insecticides based on mode of action, and list common names for each.7 Distinguish between stomach, contact, and respiratory insecticides.

What is an insect, and what are the biological characteristics of insects?I. An insect is defined as a member of a group of animals with an exoskeleton and three body parts.

Most insects have six legs and four wings.

What is an insect, and what are the biological characteristics of insects?A. An insect has an exoskeleton, made of chitin, which is the body wall of the insect.

Muscles and organs are attached to the inside wall of the strong chitin, which gives shape/support to the body and protects the organs.

What is an insect, and what are the biological characteristics of insects?B. The three major body sections of an insect are the head, thorax, and abdomen.

1. The head contains the brain, mouthparts, and most of the sensory organs, eyes, and antennae (segmented appendages that act as sensory organs). The mouthparts of insects tend to be one of two types: chewing and sucking. chewing insect bites off, chews, and swallows plant parts. Holes in leaves, buds, flowers, or other plant parts indicate the damage was done by a chewing insect. sucking insect pierces the outer layer of a plant and sucks sap from it. The insect makes a tiny hole and uses the plant juice as food.

What is an insect, and what are the biological characteristics of insects?2. The thorax provides locomotion and has wings and pairs of legs attached to it.

3. The abdomen contains organs for food digestion, respiratory functions, reproduction, and excretion.

What is an insect, and what are the biological characteristics of insects?C. Some insects are ametamorphic (without metamorphosis). The insect hatches from the egg as a small replica of the full-grown adult. Ametamorphic insects can also be viviparous (giving birth to live young with no egg stage) and parthenogenic (reproducing asexually).

How do the types of insect life cycles compare?II. Most insects reproduce sexually but differ in their development from the young to the adult stage. Insects go through a series of developmental stages, which is a process known as metamorphosis.

How do the types of insect life cycles compare?A. Incomplete metamorphosis has three stages of development: egg, nymph, and adult. Eggs hatch into nymphs, which are immature forms that resemble the adult. Nymphs usually molt and lose their exoskeleton. Molting allows the insect to grow a new, slightly larger exoskeleton. Nymphs go through this process several times before reaching the adult stage.

How do the types of insect life cycles compare?B. Complete metamorphosis four stages of development: egg, larvae, pupa, and adult. Larvae are segmented, wormlike forms that often inflict considerable damage on plants. After an active larva stage, a pupa is formed. The pupa is a resting stage before the insect becomes an adult. Most pupae are surrounded by a cocoon or protective case.

How do the feeding methods of insects compare, and what damage do insects cause to plants?III. Insects can be classified according to mouthparts. The kind of mouthpart determines how an insect feeds. Control measures can be selected based on the way the insects feed because the damage will vary according to the type of mouthpart.

How do the feeding methods of insects compare, and what damage do insects cause to plants?A. Insects may have chewing, piercing and sucking, sucking, or sponging mouthparts.

1. Insects with chewing mouthparts cut, tear, crush, and chew leaves, stems, roots, flowers, and fruit. Examples of insects with chewing mouthparts are the Japanese beetle, grasshoppers, and the larva of moths and butterflies.2. Insects with piercing and sucking mouthparts puncture plant tissues and suck the internal fluids. Examples of insects with piercing and sucking mouthparts are aphids, scale insects, and leafhoppers. Damage often appears as tiny spots.

How do the feeding methods of insects compare, and what damage do insects cause to plants?3. Insects with sucking or siphoning mouthparts draw fluids, such as nectar, up the tubular-shaped mouthpart. Butterflies and moths have sucking mouthparts.4. Some insects, such as houseflies, have sponging mouthparts. As is the case with houseflies, insects with sponging mouthparts coat a food with saliva and sponge it up.

How do the feeding methods of insects compare, and what damage do insects cause to plants?B. Damage caused by insects may affect photosynthesis through defoliation; it may also damage fruits, stems, and roots. Most plants can withstand low to moderate infestations, but heavy infestations can kill plants.

Some insects also carry diseases from plant to plant.

How do the feeding methods of insects compare, and what damage do insects cause to plants?C. Different types of insects feed on different parts of plants.

1. External feeding insects chew or suck from the exterior of the plant. They feed on the leaves, stems, buds, or fruit.

2. Internal feeding insects are chewing insects that cause damage to the inside of a plant. They feed internally on plant tissues. The damage may not be evident for several days or longer.

3. Subterranean insects are insects in the soil that attack the roots of plants. In some cases, they may attack root-type structures.

What are some methods of insect control?IV. Several different methods can be used to manage insect populations.

A. Biological control is the use of living organisms to reduce pest populations. These beneficial organisms are natural enemies of pests. They attach, live in, or infect pest hosts. Parasites, predators, and pathogens are all used as biological controls.

What are some methods of insect control?B. Cultural control is used to make the crop environment unsuitable for pests to feed, live, or reproduce. Cultural control also improves the health of the crop. Examples of cultural controls include soil tillage, crop rotation, harvest or planting date adjustment, irrigation schemes, variety selection, clean culture, and trap crops.

1. Clean culture refers to any practice that removes breeding or overwintering pest sites.

2. A trap crop is a susceptible crop planted to attract a pest to a localized area where the trap crop is destroyed or treated with a pesticide.

What are some methods of insect control?C. Mechanical control is used to physically remove or exclude pests. It includes hand destruction and the use of screens to keep out insects and traps to catch them.

What are some methods of insect control?D. Genetic control of plant pests involves the use of a genetically modified organism (GMO). Plant breeders are constantly working to develop varieties and hybrids that are resistant to or tolerant of pest feeding. The biggest advantage of genetic control is that the development of resistant varieties and hybrids is a more stable method since genetic resistance lasts for several years.The genetic control of insects and mites can be divided into three groups.

What are some methods of insect control?1. Nonpreference control allows plant breeders to alter the plants biochemistry or constituents so a particular variety or hybrid is less palatable to the pest. If the taste, aroma, color, or texture of the crop plant is undesirable to the pests, they move to a different variety or a different host plant (e.g., another crop or a weed).2. With antibiosis control, the crop plant components have a harmful effect on the growth or reproduction of the pest when it feeds on it.3. Tolerance control allows the host plant not to suffer economic damage even though it may be heavily infested with the pest.

What are some methods of insect control?E. Chemical control is the use of pesticides to reduce pest populations. Pesticide resistance is the ability of an organism to tolerate a lethal level of a pesticide. Pest resurgence refers to a pests ability to repopulate after control measures have been eliminated or reduced.

What are the types of insecticides, and what are some common names for each?V. Pesticide families include carbamates, organochlorides, organophosphates, pyrethroids, and biological insecticides.

A. Carbamate insecticides are moderate to very high in toxicity. Insecticides from this family include aldicarb, carbaryl, carbofuran, methomyl, pirimicarb, and propoxur.

What are the types of insecticides, and what are some common names for each?B. Organochloride insecticides are highly toxic. Insecticides from this group are very dangerous because they are absorbed by the fatty tissue of animals. The insecticides do not break down for years. Because of this, the toxins accumulate in the body of animals and can flow down the food chain. Insecticides from this family include DDT, dicofol, endosulfan, lindane, and methoxychlor.

What are the types of insecticides, and what are some common names for each?C. Organophosphate insecticides have low to very high toxicity. Insecticides from this family include acephate, azinphos-methyl, chlorpyrifos, diazinon, dichlorvos, dimethoate, fenthion, malathion, and parathion.

What are the types of insecticides, and what are some common names for each?D. Pyrethroid insecticides kill insects by disrupting their nervous systems. These are nonpersistent and much less acutely toxic than organophosphates and carbamates. Pyrethrins and pyrethrum are the most frequently used home and garden insecticides in the United States. They are often used in indoor sprays, pet shampoos, and aerosol bombs to kill flying and jumping insects.

What are the types of insecticides, and what are some common names for each?E. Biological insecticides include plant toxins (e.g., caffeine, nicotine, pyrethrum, and rotenone). Another example is a bacterial disease caused by Bacillus thuringiensis, which is effective on insect larvae and is considered environmentally friendly.

What are the types of insecticides based on mode of action, andwhat are common names for each?VI. Different insecticides kill insects in different ways. The way in which a pesticide kills or inactivates a pest is called mode of action. Some insecticides affect the nervous system. Others affect water balance, oxygen metabolism, molting or the maturation process, or other physiology aspects. The mode of action of a number of the newer insecticides is not fully understood.

What are the types of insecticides based on mode of action, andwhat are common names for each?A. Organophosphates, including Chlorpyrifos, diazinon, and malathion, interfere with the transmission of nerve impulses. Their point of action is the synapse, which is the tiny gap between one nerve fiber and the next. Organophosphate enzymes are involved in this process. Symptoms from exposure to these insecticides are hyperactivity, uncoordinated movements, tremors, convulsions, or paralysis.

What are the types of insecticides based on mode of action, andwhat are common names for each?B. Carbamates inhibit the action of cholinesterase, such as organophosphates. Hyperactivity, uncoordinated movements, tremors, convulsions, or paralysis often result. Carbaryl, bendiocarb, and propoxur are examples of carbamates.

What are the types of insecticides based on mode of action, andwhat are common names for each?C. Pyrethroids, such as ermethrin, cypermethrin, fenvalerate, and cyfluthrin were synthesized by chemists who studied the structure of insecticidal pyrethrins. Pyrethroids last longer than their natural counterparts. They disrupt the normal transmission of nerve impulses by affecting the potassium or sodium ion channel in nerve cells.

What are the types of insecticides based on mode of action, andwhat are common names for each?D. Insect growth regulators are effective with immature insects. Insect growth regulators cause an insect to change into an adult or pupa when the insect is not physiologically ready. Methoprene and pyriproxifen are examples of insect growth regulators.

What are the types of insecticides based on mode of action, andwhat are common names for each?E. Chlorinated hydrocarbons, including methoxychlor and dicofol, interfere with the normal movement of potassium and sodium ions across nerve cell surfaces. As a result, normal nerve-cell functions are prevented.

What are the types of insecticides based on mode of action, andwhat are common names for each?F. Microbial insecticides consist of microorganisms that attack insects. To be effective, insects must eat insecticides based on viruses. Inside the insect, the viruses multiply. Then the insects cells burst and die. Bacillus thuringiensis also needs to be eaten by insects. The bacteria attack the gut lining, invade the insects body, and multiply. Fungal insecticides attack from the outside. Fungal spores land on the insects body, grow through the cuticle and exoskeleton, and spread throughout the body.

What are the types of insecticides based on mode of action, andwhat are common names for each?G. Insecticidal soaps are usually composed of potassium salts of fatty acids. Insecticidal soaps must contact the outer body covering of insects where the soaps can penetrate and dissolve nearby cells. As a result, cell fluids leak out. In addition, the cells collapse, resulting in dehydration and death.

What are the types of insecticides based on mode of action, andwhat are common names for each?H. Oils are used with mites, scale insects, and aphid eggs. The oil kills these pests by smothering them.

How do contact, stomach, and respiratory insecticides compare?VII. Insecticides are classified by how they enter an insects body. Three general groups of insecticides are contact, stomach, and respiratory.

How do contact, stomach, and respiratory insecticides compare?A. Contact insecticide is absorbed through the skin or exterior of an insect. The chemical must be applied directly on the insect. This type of insecticide is normally used with sucking insects.

How do contact, stomach, and respiratory insecticides compare?B. Stomach insecticide is effective when eaten. The chemical is applied to the plant parts, which are eaten by the insect. This type of insecticide is most effective on chewing insects.

How do contact, stomach, and respiratory insecticides compare?C. Respiratory insecticide enters the respiratory system of the insect. It is commonly called a fumigant. This type of insecticide is used in enclosed places.

REVIEW1. What is an insect, and what are the biological characteristics of insects?2. How do the types of insect life cycles compare?3. How do the feeding methods of insects compare, and what damage do insects cause to plants?4. What are some methods of insect control?5. What are the types of insecticides, and what are some common names for each?6. What are the types of insecticides based on mode of action, and what are common names for each?7. How do contact, stomach, and respiratory insecticides compare?