What is the order of the insect evidence, according to the life cycle of the insect?

James Robinson

Insects are a major limiting factor in commercial vegetable product. Minor insect damage lowers the crop's value considering the market demands clean, unblemished produce. Growers need to quickly recognize insect bug and practice early command to forestall a buildup and keep insect pests from getting out of command.

Insect Life Cycle

Insects either accept a complete or incomplete life wheel. Insects in the complete life cycle group have four distinct stages, the egg, larvae, pupae and adult. Examples of these insects are beetles and moths. Beetles lay their eggs either singly or in groups, and they hatch into either grubs or larvae that movement about freely on the plant feeding on roots, tubers, leaves, or fruits. Afterward reaching maturity, they and then pupate (the resting stage) and develop into adults. Adult beetles also may damage constitute parts, so ii dissentious stages may exist. Effigy Half dozen-ane depicts growth stages for insects having a consummate life bike.

Figure VI-1. Complete Life Cycle

Moths and butterflies besides accept a complete life bike similar to beetles except that the damaging stage is the larvae or worm stage which usually feeds on the stems, leaves or fruits. The adult stage, moths and collywobbles, feed on nectar or may not feed at all. Insects with a consummate life cycle almost always have a chewing mouthpart.

Insects with incomplete life cycles include grasshoppers and true bugs (stink bug and squash bugs). Many insects in this category have piercing, sucking mouthparts and suck juice from plants. Some, such every bit the grasshopper, chew on leaves and stems. Regardless, insects with an incomplete life bike are unique in that they hatch from eggs into tiny nymphs that resemble the adult stage. They stay in the nymphal stage for several weeks, while growing and molting into larger insects until they reach adulthood. Adults have fully developed wings and tin can fly great distances. Nymphs either do not have wings or have wings that cannot be used for flight.

Insects with an incomplete life cycle can be controlled at any stage, but are easier to control in the nymphal stage simply after they hatch from the eggs. Figure VI-2 depicts the developmental stages of insects with incomplete life cycles.

Figure VI-2. Incomplete Life Cycle. Image courtesy of North Dakota State University

Insect Injury

Insects injure plants past chewing leaves, stems and roots, sucking juices, egg laying or transmitting diseases.

Injury by Chewing Insects

Insects accept their food in a diversity of ways. One method is by chewing off external found parts. Such insects are called chewing insects. Information technology is easy to come across examples of this injury. Perhaps the best way to gain an idea of the prevalence of this blazon of insect impairment is to try to notice leaves of plants with no sign of insect chewing injury. Cabbageworms, armyworms, grasshoppers, the Colorado potato protrude and the autumn webworm are common examples of insects that cause chewing injury.

Injury by Piercing-Sucking Insects

Another important method which insects use to feed on plants is piercing the epidermis (peel) and sucking sap from cells. In this case, only internal and liquid portions of the found are swallowed, while the insect feeds externally on the plant. These insects have a slender and sharp pointed part of the mouthpart which is thrust into the found and through which sap is sucked. This results in a very different only nevertheless astringent injury. The hole made in this way is so small that it cannot be seen with the unaided centre, but the withdrawal of the sap results in either minute white, brown or red spotting on leaves, fruits and/or twigs; leaf curling; deformed fruit; or a general wilting, browning and dying of the entire plant. Aphids, scale insects, squash bugs, leafhoppers and plant bugs are examples of piercing-sucking insects.

Injury by Internal Feeders

Many insects feed within plant tissue during a part or all of their destructive stages. They gain archway to plants either in the egg phase when the female person thrust into the tissues with sharp ovipositors and eolith the eggs in that location, or by eating their fashion in later they hatch from the eggs. In either case, the hole by which they enter is nigh ever minute and often invisible. A large hole in a fruit, seed, nut, twig or trunk mostly indicates where the insect has come out, and non the point where information technology entered.

The principal groups of internal feeders are indicated by their mutual grouping names: borers; worms or weevils in fruits, basics or seeds; leaf miners; and gall insects. Each grouping, except the third, contains some of the foremost insect pests of the world. In nearly all of them, the insect lives inside the plant during only a part of its life and emerging sooner or later equally an adult. Control measures for internal feeding insects are most constructive if aimed at adults or the young stages prior to their entrance into the establish.

A number of internal feeders are small enough to detect comfortable quarters and an abundance of food between the upper and lower epidermis of a foliage. These are known equally leaf miners.

Gall insects sting plants and crusade them to produce a construction of deformed tissue. The insect then finds shelter and abundant food within this plant growth. Although the gall is entirely establish tissue, the insect controls and directs the form and shape it takes as it grows.

Injury past Subterranean Insects

Subterranean insects are those insects that attack plants below the surface of the soil. They include chewers, sap suckers, root borers and gall insects. The attacks differ from the above basis forms just in their position with reference to the soil surface. Some subterranean insects spend their unabridged life bike beneath ground. In other subterranean insects, at that place is at least one life stage that occurs to a higher place the soil surface; these include wireworm, root maggot, pillbug, strawberry root weevil, and corn rootworm. The larvae are root feeders while the adults live to a higher place ground.

Injury by Laying Eggs

Probably 95% or more than of insect injury to plants is acquired by feeding in the various ways but described. In addition, insects may damage plants by laying eggs in critical constitute tissues. As soon equally the young hatch, they desert the found causing no further injury.

Utilise of Plants for Nest Materials

In addition to laying eggs in plants, insects sometimes remove parts of plants for the construction of nests or for provisioning nests.

Insects as Disseminators of Plant Diseases

In 1892, a plant illness (fireblight of fruit trees) was discovered to exist spread by an insect (the honeybee). At present, there is prove that more than 200 plant diseases are disseminated by insects. The majority of them, near 150, vest to the group known equally viruses; 25 or more than are due to parasitic fungi; 15 or more are bacterial diseases; and a few are caused by protozoa.

Insects may spread plant diseases in the following ways:

• By feeding, laying eggs or boring into plants, they create an entrance point for a disease that is not really transported by them.
• They carry and disseminate the causative agents of the illness on or in their bodies from ane plant to a susceptible surface of another found.
• They carry pathogens on the outside or inside of their bodies and inject plants hypodermically as they feed.
• The insect may serve as an essential host for some part of the pathogens life bike, and the illness could not complete its life cycle without the insect host.

Examples of insect vectored plant diseases are shown below.

Disease	Vector
Fireblight (bacterial)	Pollinating Insects
Tomato plant curly top (virus)	Beet leafhopper
Cucumber mosaic (virus)	Aphids

Benefits and Value of Insects

Insects must be studied carefully to distinguish the benign from the harmful. Producers have frequently gone to groovy trouble and expense to destroy insects, only to acquire later that the insect destroyed was non merely harmless, but information technology was really engaged in saving their crops by eating subversive insects.

Insects are beneficial to the vegetable grower in several means:

• Insects assist in the production of vegetables past pollinating the blossoms. Melons, squash and many other vegetables crave insects to carry their pollen earlier fruit set.
• Parasitic insects destroy other injurious insects past living on or in their bodies and their eggs. Insects too act as predators, capturing and devouring other insects.
• Insects destroy various weeds in the aforementioned ways that they injure ingather plants.
• Insects improve the physical condition of the soil and promote its fertility past burrowing throughout the surface layer. Also, the dead bodies and droppings of insects serve as fertilizer.
• Insects perform a valuable service equally scavengers past devouring the bodies of dead animals and plants and past burying carcasses and dung.

Many of the benefits from insects enumerated above, although 18-carat, are insignificant compared with the expert that insects do fighting among themselves. There is no incertitude that the greatest single gene in keeping establish-feeding insects from overwhelming the rest of the globe is that they are fed upon by other insects.

Insects that eat other insects are considered in 2 groups known as predators and parasites. Predators are insects (or other animals) that take hold of and devour other creatures (called the prey), usually killing and consuming them in a single meal. The prey more often than not is smaller and weaker than the predator. Parasites are forms of living organisms that alive on or in the bodies of living organisms (chosen the hosts) from which they get their food, during at least one stage of their existence. The hosts usually are larger and stronger than the parasites and are not killed promptly merely go along to live during a menstruum of shut clan with the parasite. Predators are typically very agile and have long life cycles; parasites are typically sluggish and tend to have very brusk life cycles.

Insect Control

Insect control is also of import to keep the pests from spreading to other crops, and it may help reduce the incidence of disease by killing insect vectors. Insects attacking vegetables tin can be divided into three categories:

• Soil Insects
• Chewing Insects
• Sucking Insects

Soil Insects

Soil insects include wireworms, white grubs, fire ants, cutworms, seed maggots and the sweet potato weevil. These insects tin be damaging considering they feed on the roots, stems and tubers of plants. Oft soil insects, especially cutworms, are common in uncultivated soil sites that have had grass and weeds growing the previous flavor. These undisturbed areas often harbor high populations of soil insects. Once seeds or transplants are planted, soil insects are difficult to control and may begin feeding immediately on the crop. There is a real need for producers to audit fields for soil insects prior to planting. One or two soil insects per foursquare foot of soil can cause serious damage.

Oft soil insects are clumped in a field, that is, they may be in one area and not in another. Low areas or those areas with the nearly vegetation oftentimes hold the well-nigh insects. Decision-making soil insects is much easier if done prior to planting. Most insecticides for the control of soil insects should be practical 6 weeks before planting and incorporated into the elevation 6 inches of the soil. Liquid or granular materials may exist used. These tin can either be broadcast or banded in the row. Sometimes producers will apply insecticides at planting. Make certain to read the label for proper rates and application techniques. Some insecticides may interfere with seed germination and should not be placed in the furrow in contact with the seed.

Chewing Insects

Many chewing insects accept a complete life bicycle. Therefore, depending on species, there may be i or two damaging stages. Grasshoppers have a chewing-type mouthpart but have an incomplete life cycle. Chewing insects include all species of beetles, grasshoppers and moths and butterfly larvae (well-nigh often called worms).

Chewing insects damage foliage, stems and fruit. They may become as numerous equally to completely defoliate plants. Eggs of most insects are laid on the plant, and the larvae upon hatching brainstorm to feed. Others may invade the crop by "marching in" or by flight into the field.

Control of chewing insects is basically twofold. One, the grower must scout for eggs and pocket-size larvae that brainstorm to feed; two, he must watch for the adults and command them when necessary. Control of these insects is important in the early infestation of the found. Often, the insect after hatching may diameter into the fruit or stem and be hidden from pesticide applications.

These insects often become numerous considering producers exercise not begin handling early on enough. Information technology is vital that fields exist watched and these insects controlled at the earliest possible moment.

Sometimes a single awarding timed properly will control a generation. Withal, repeated applications are needed to command others like the corn earworm in sweet corn.

Sucking Insects

Sucking insects include aphids ("plant lice"), stink bugs, squash bugs, leafhoppers and spider mites. Spider mites are non insects but are merely as dissentious and numerous as are some insects. Sucking insects have an incomplete life bike. After hatching from the egg, they may begin to feed and move most on the plant.

They are usually attracted to the almost succulent part of the plant. Aphids usually are found in the terminal or on flowers. Stink bugs and squash bugs readily feed on the tender fruit. These insects damage the plant past reducing the vigor or by injecting a toxin or disease-causing organisms into the plant. Heavy feeding may crusade flowers to abort or the leaves to turn yellow and fall off. Feeding on the fruit may cause catfacing injury, hard spots or twisted and misshapen fruit.

Control is easiest to obtain soon afterwards the insects hatch from eggs. This is when the insects are the smallest and most vulnerable to the pesticide. Wait for egg clusters, and then that timing of the insecticide can be more accurate. Most true bugs have large eggs that can exist seen without the aid of a magnifying glass. They are frequently on the undersurface of leaves and laid in tight groups and glued together, or in the instance of squash bugs, they may be laid singly but in a loose fitting group and not glued together.

Pest Control with a Minimum of Chemicals

The "if a trivial is practiced, more will be better" attitude leads to a serious misuse of pesticides.

Overuse of pesticides has a number of adverse effects:

• Food products may comprise unsafe pesticide residues if improperly treated with pesticide.
• Beneficial insects, earthworms and birds may be harmed or killed along with harmful insects if pesticides are carelessly used.
• Each fourth dimension producers spray they betrayal themselves to the possibility of inhalation or absorption of the toxin.
• Careless use of pesticides about water may contaminate water supplies.
• Misuse of pesticides tin can pb to the development of chemical resistance in the target pest.
• The use of pesticides can lead to outbreaks of secondary pest species.

A growing public concern over the use and misuse of pesticides has led increasing numbers of vegetable producers to seek means of natural pest control. Although some people do not have the time or knowledge to practice all available alternative methods for decision-making pests, there are many cultural practices which will help reduce losses. Proper soil training, conscientious plant selection and good cultural practices tin be combined with biological and mechanical controls to reduce the need for chemic pesticides.

Temperature, humidity, precipitation and natural enemies all influence insect populations. In some years, troublesome insects may not be numerous enough to significantly damage plants. In other years, large insect populations may cause serious damage or completely destroy host plants.

Constructive control of specific insects must be preceded by proper identification of these insects. Once an insect's identity is known, you tin learn about its life cycle, seasonal cycle, habits and host plants, and thus do more effective control measures.

Several control methods are often combined in order to minimize damage by insect pests. Since insect control methods vary in their effectiveness, you lot may wish to select alternative methods to represent with differences in constitute growth and productivity, insect damage, weather weather and cultural practices. Various control methods will at present be considered.

Resistant Plant Varieties

Utilise bachelor plant species or varieties which are resistant to, or at least tolerant of, insect activeness. Insect resistance in plants frequently is interpreted as pregnant "immune to insect damage." Actually, it is a term for distinguishing plant varieties which exhibit less insect damage when compared to other varieties under similar growing and pest population conditions. Some varieties may be less "tasty" to insect pests, or may possess certain physical or chemical properties which discourage insect feeding or egg-laying, or may exist able to support large insect populations without suffering appreciable damage.

Before buying seeds or plants, cheque with your local county Extension amanuensis for information on resistant varieties which volition grow well in your surface area. Examples of vegetable varieties that take shown resistance to specific insect pests are listed in Tabular array VI-one. Some varieties may exist resistant to insect assail, but may be bailiwick to certain restrictions such every bit soil pH, drainage or temperature. Your experience with unlike varieties volition signal the ones all-time suited for your performance.

Table 6-i. Vegetable Varieties that have shown Some Resistance to Specific Insect Pests

Vegetable	Variety	Insect resistance
Bean (snap)	Wade	Striped Flea Protrude
Broccoli	De Cicco	Striped Flea Protrude
Cabbage	Early Globe Carmine Acre Round Dutch	Cabbage Looper, Imported Cabbageworm Cabbage Looper, Imported Cabbageworm Cabbage Looper, Imported Cabbageworm
Cabbage (Chinese)	Michihili	Diamondback Moth
Collard	Georgia	Striped Flea Beetle, Harlequin Issues
Corn (sugariness)	Gilt Security	Corn Earworm
Cucumber	Ashley Piccadilly Poinsett	Pickleworm, Spotted Cucumber Beetle Pickleworm Spotted Cucumber Beetle
Kale	Vates	Diamondback Moth
Mustard	Florida Broadleaf	Diamondback Moth, Striped Flea Beetle
Radish	Cherry Belle White Icicle	Diamondback Moth, Harlequin Bug Harlequin Bug
Squash	Early on Prolific Straightneck White Bush Scallop Zucchini	Pickleworm, Striped Cucumber Beetle Pickleworm, Striped Cucumber Protrude Striped Cucumber Beetle
Sweetpotato	Centennial Precious stone	Sweetpotato Flea Beetle, Tater Wireworm Sweetpotato Flea Protrude, Potato Wireworm
Turnip	Seven Summit	Diamondback Moth, Striped Flea Beetle
Rutabaga	American Purple Meridian	Diamondback Moth, Striped Flea Protrude

Cultural Controls

Many cultural practices can exist used to reduce the potential for, or actual damage of plants acquired past insects:

• Plowing and cultivating exposes soil insects to adverse weather weather condition, birds and other predators. In improver, deep plowing volition bury some insects and forestall their emergence.
• Crop rotation tin can exist constructive confronting insects that develop on a narrow range of nutrient plants and likewise against insects with short migration ranges. Movement of crops to different sites will isolate such pests from their food source. If an alternate site is not available, then change the sequence of plants grown in the field. Do not found members of the same plant family in the aforementioned location in sequent seasons. For example, do not follow melons with cucumbers or squash.
• Proper use of fertilizers and water will induce salubrious plant growth and increase the capability of plants to tolerate insect damage. However, excessive amounts of organic matter or manure tin can encourage millipedes, pillbugs, white grubs and certain other pests.
• Changes in planting or harvesting time often volition reduce institute damage or keep insect pests separated for susceptible stages of the host plant. Delayed planting, until the soil is warm enough for corn and bean seeds to germinate quickly, reduces seed maggot damage. Hot caps or row covers placed over plants used during the early flavour non only will preserve heat, just also volition protect plants from damaging wind, hail and insects. In some situations, a healthy transplant will overcome insect damage more easily than a pocket-size found developing from seed in the field.
• Removing soil residues and disposing of weeds and other volunteer plants eliminates food and shelter for many insect pests such every bit cutworms, webworms, aphids, white grubs, millipedes and spider mites. When plants end producing, till them into the soil or have them to the compost pile.
• Companion planting (an orderly mixing of crop plants) is a cultural practice aimed at diversifying insect populations. Numerous claims have been made nigh the ability of certain plants to protect sure other plants from insect damage. However, no data from scientific studies are bachelor to prove the value of companion plantings.

Mechanical Control Methods

Preventive devices ofttimes are easy to use, although their effectiveness varies. Here are examples of such devices:

• Cheesecloth or spun bound polyester row covers for plant beds, hot beds and cold frames to forbid insect egg laying.
• Mesh covers for tomatoes and other plants to keep out large insects and birds.
• Aluminum foil mulch to repel aphids.

Blackness lite traps are effective tools for monitoring insect species in a given area, just commonly provide little protection for the crop. Calorie-free traps attract both harmful and beneficial insects that ordinarily would not be institute in the area. Attracted insects may not be defenseless in the traps, but may remain in the area, and the harmful ones may cause damage later. Also, some species such as wingless insects and those insects but active in the daytime are non caught in the traps. Consequently, the value of blackness light traps is questionable. Where black lights are used, information technology is recommended that they be placed fifty to 75 feet away from the area which is to be protected.

Biological Control Methods

Generally, biological control can be divers as the direct or indirect use of parasites, predators or pathogens (bacteria, viruses, fungi protozoans) to agree pest insect populations at depression levels to avoid economical losses. Biological control methods fall into iii categories:

• Introduction of natural enemies which are not native to the expanse (these enemies must and then institute and perpetuate themselves).
• Enlarging existing populations of natural enemies past collecting, rearing and and then releasing them back into the surround.
• Conservation of beneficial organisms past such means as the judicious employ of pesticides and the maintenance of alternate host insects, so parasites and predators tin keep to develop.

Many beneficial organisms occur naturally effectually crops, but often they are non numerous enough to control a pest before it inflicts astringent damage. In fact, parasites and predators appear to be near effective when a pest population has stabilized or is relatively depression. Their influence on an increasing pest population ordinarily is minimal since any increase in parasite and predator numbers depends on an even greater increment in pest numbers. Pathogens, yet, seem to be most effective when pest populations are big. Consequently, the nature of the host insect-natural enemy human relationship makes information technology impossible to have an insect-gratuitous environment and at the same time maintain sizable populations of beneficial insects.

The following is a list of some of the more than popular biocontrol agents:

• Bacillus thuringiensis: (Dipel, Thuricide, Biological Worm Killer). This bacterial insecticide provides effective control of the larvae of several moths and butterflies. The bacterial spores are harmless to warm blooded animals and beneficial insects.
• Bacillus popilliae: (Milky Spore, Doom, Japedimic). This bacterial insecticide controls grubs of Japanese beetles in the eastern U.Due south., and some testing has been washed for control of white grubs (Phyllophaga spp. and Cotinis spp.) in Texas. It has not been effective against the chief white chow species in Texas.
• Nosema locustae: A spore (Protozoan) used to control grasshoppers. The material is sprayed on the plants which grasshoppers ingest. The spores germinate within the grasshopper, causing death. Control is extremely dull and growers may non be satisfied with results. Baits accept proven more effective.
• Trichogramma wasp: Adult wasps are bachelor from several sources. The tiny wasps assault the eggs of more than 200 pest species, including cutworms, armyworms, fruit worms and many moth and butterfly eggs deposited in orchards and field crops. Wasps should exist released when the moths are commencement seen, but a sequence of releases throughout the flavour is preferable to a single, large release. Results volition depend on the timing of the releases, selection of Trichogramma species and placement of wasps near host egg masses.
• Green lacewings (Chrysopa): The larvae, known as aphid lions, prey on many vegetable pests including aphids, spider mites, leafhoppers, thrips, moth eggs and pocket-size larvae. Adult lacewings feed on honeydew, nectar and pollen. Introduced lacewings must accept a readily available supply of food, or they will get out. Eggs are sometimes bachelor.
• Praying Mantis: Egg cases, containing about 200 individual eggs, are bachelor from a number of sources. The mantis is a voracious predator. In addition, it is cannibalistic immediately after hatching, then few nymphs survive the first week of life. Even so, the mantis is a poor searcher for food and unremarkably waits for prey to come to it. This greatly influences the kinds of insects it captures and kills. Food preferences include grasshoppers, crickets, bees, wasps and flies.
• Lady beetles: Adult beetles are available from several sources. Aphids are the preferred hosts, merely lady beetles volition eat mealy bugs, spider mites and certain other soft bodied pests and eggs. They do not, notwithstanding, kill grubs, caterpillars and other beetles. Unless an ample supply of live aphids or other hosts are available at the release point, lady beetles will disperse and leave the area. In some cases, nearly of the beetles will go out the area regardless of the availability of nutrient. Lady beetles can be encouraged to remain on a institute by using small meshed screen cages (remove cages earlier they devour all of their nutrient supply). In hot dry conditions these beetles enter a nonactive (aestivation) state in which feeding and reproduction terminate. Footling control from lady beetles tin can be expected during this time.

Natural Insecticides

Despite all efforts, noninsecticidal methods at times will fail to prevent excessive insect damage. At such times, the apply of insecticides may be the only alternative left. Insecticides chosen should have only low toxicity for humans and other warm blooded animals. They should be used only when needed and according to label directions. A better understanding of insecticides will enable yous to use these materials more effectively and to realize that they can be an assistance without harming you or the environment.

• Pyrethrum: Botanical Insecticide. This slightly toxic insecticide is derived from the flowers of a species of Chrysanthemum imported mainly from Kenya and Republic of ecuador. The fabric causes rapid paralysis of near insects, but the insects normally recover unless the pyrethrum is used in combination with a synergist or other poison. Pyrethrum, mixed with synergists such as piperonyl butoxide or piperonyl cyclonene to increase toxicity and produce longer residual activeness, is used extensively in crop sprays and dusts. This chemic is registered for apply on most vegetables at whatever time during the growing season.
• Nicotine: Botanical Insecticide. Pure nicotine is a tobacco extract highly toxic to warm blooded animals. The insecticide unremarkably is marketed as a twoscore% liquid concentrate of nicotine sulfate, which is diluted in water and applied as a spray. Dusts tin irritate the skin. Nicotine is used primarily for piercing-sucking insects such as aphids, whiteflies, leafhoppers and thrips. Nicotine is more effective when applied during warm weather. It degrades quickly, and then it tin be used on many food plants nearing harvest. It is registered for use on a wide range of vegetable and fruit crops.
• Sabadilla Botanical Insecticide: Sabadilla is obtained from the seeds of a lily-like plant and acts every bit both a contact and breadbasket poison for insects. It is not particularly toxic to mammals, but does crusade irritation of the optics and respiratory tract. A mask should be worn when working with this insecticide. This material deteriorates speedily upon exposure to low-cal and tin be used safely on food crops before long before harvest. Sabadilla generally is used as a 5 to 20% dust or as a spray.
• Rotenone: Botanical Insecticide. Rotenone is extracted from the roots of Derris plants in Asia and cube plants in South America. This general insecticide is harmless to plants, highly toxic to fish and many insects, moderately toxic to mammals, and it leaves no harmful residues on vegetable crops. It acts as both a contact and stomach toxicant to insects. Information technology is slow interim, and in the presence of sun and air, its effectiveness is lost inside a week after awarding. Vesture a mask during application because rotenone can irritate the respiratory tract. Rotenone dusts and sprays have been used for years to control aphids, certain beetles and caterpillars on plants.

Organic Controls

Growers have been using soap to command insects since the early on 1800's. Researchers have not nonetheless determined exactly how soaps work. Some soap simply launder off the outer waxy coating of the insect cuticle, destroying its watertight nature and causing the insect to dry up and die. Other soaps have additional insecticidal properties which may affect the nervous organization. These soaps appear to accept toxic activity only confronting constitute eating insects, and thus may spare beneficial insects such equally lady beetles, honeybees, lacewings and predatory mites. Although a number of soaps tested have insecticidal properties, only Safer'south Insecticidal Soap is currently registered for utilize on edible crops. It controls such pests as spider mites, aphids, mealybugs, whiteflies, harlequin bugs, stink bugs and thrips.

Organic growers have been using a spray mixture containing onions, garlic and pepper mixed together to control insects for many years. Inquiry indicates that of combination of these materials have been erratic and in many cases ineffective for insect control. Sprays of nutrient-derived substances do not appear to be proficient choices as a pesticide. Some success may exist achieved with them, but information technology is likely to be sporadic. Spraying several times a week might aid to bring infestations under control. Command with one application should non be expected.

Controlling Insects with Pesticides

Insects oftentimes pass the winter in a life phase that can harm crops early on the side by side season. They may pass the winter in the field in grass, trash or in weedy fence rows. Squash bugs spend the winter in the adult stage and often invade fields soon after planting and begin feeding. Good squash bug control can exist accomplished if producers realize this and treat them earlier the plants actually begin to bloom. Deep plowing of fields in the winter can eliminate some overwintering stages.

Fall grown vegetables are usually heavily attacked by insects. More than insecticides may have to be used on fall vegetables.

Some cultural control measures tin be used to suppress insect force per unit area. Examples of these measures are deep plowing, decision-making weeds and grass around the field and destroying crop residue soon after harvest.

Carbaryl (Sevin) insecticide is an fantabulous material, and vegetables sprayed with Carbaryl can exist harvested presently subsequently spraying. However, repeated use of Carbaryl oftentimes results in a spider mite outbreak.

Employ alternate classes of insecticides in the spray program. Do not rely on 1 product for the entire season. Exist prepared to switch when insect pressure level or different species are found. For specific insect control recommendations, refer to the Texas AgriLife Extension publication B-1305, "Texas Guide for Controlling Insects on Commercial Vegetable Crops."

Various reference materials are available in the form of USDA publications and books. A skilful reference book is 'Destructive and Useful Insects' past Metcalf, Flint, and Metcalf. The Peterson Field Guide series are also excellent references. 'The Field Guide to the Insects of America North of Mexico' by D.J. Borror and R.E. White is an first-class reference for the identification of the various insects.

Safe Use of Pesticides

When it is necessary to use insecticides, use them wisely and safely. The following tips will help you brand ameliorate use of insecticides:

• Audit plants and monitor insect numbers and activity on a regular ground. Pay particular attention to underside of leaves where insects and their eggs frequently occur. If treatments are practical when an infestation first starts, insect numbers can be maintained at lower levels much more hands and with smaller amounts of chemicals.
• When applying insecticides to plants, treat all institute surfaces unless otherwise stated on the product's label. This ensures that an insect anywhere on the institute will be exposed to a lethal amount of the chemical. Do not apply insecticides to wilted plants or during the hottest function of the solar day. Apply dusts only when the wind is calm and plants are dry. Sprays should be applied when the wind is no more 5 to 10 mph. Retreatment may exist necessary after rainfall.

Common Insects Attacking Vegetable Crops

Soil Insects

Wireworm

Plants Attacked: Corn, small grains, grasses, potatoes and other root crops such as sugariness potatoes.

Description: Adults are normally hard shelled, dark-brown gray or nearly black, somewhat elongated with the torso tapering toward each finish. The larvae usually are hard, dark dark-brown, smooth, wire like worms from ½ to one½ inches long when grown.

Life History: Immature adults remain in the soil until spring. The subsequent egg phase requires a few days to a few weeks to hatch. Larvae spend from ii to six years in the soil feeding on roots of grasses and other plants. Pupation usually is completed in a few weeks.

Damage: Crops may fail to emerge, or stay thin and patchy. Wireworms feed on seed and hush-hush constitute parts. On potatoes they crusade modest holes or trail-like appearance in their feeding habits.

White Grubs

Plants Attacked: Corn, beans and potato tubers and other root vegetable crops.

Description: Developed beetles are from ½ to 1 inch long, vary from light to dark dark-brown and are robust in course. The larvae are white, curved bodied grubs with dark-brown heads and three pairs of legs. The hind part of the belly appears darker considering soil particles inside prove through the torso wall. In that location are probably 100 species, and many cause damage.

Life History: The life bike of the more abundant species extends over three years. In late spring pearly white eggs are deposited from 1 to viii inches deep in the soil. Approximately 3 weeks later the eggs hatch, and the larvae feed on roots and decaying thing. In fall when cooler temperatures prevail, the larvae immigrate downwards and remain inactive until the following jump when they return to feed on constitute roots near the soil surface. Greatest harm occurs at this fourth dimension. At the next autumn, they begin to go deep into the soil, returning to the surface in the bound of the third year; they feed until June. Then oval, earthen cells are made and pupation follows. Developed beetles form in the pupae in a few weeks; they remain in the cells throughout the wintertime and sally from the soil the following year to begin feeding, mating and egglaying. In Texas the period from egg to adult seems to be two years for almost species.

Damage: Almost astringent harm by grubs occurs on crops which follow grass sod the next yr. Grubs feed on the roots of crops attacked and destroy the root organisation.

Chewing Insects

Fruit Worms

There are many types of worms that feed on plants, the fruit or leaves and buds of the plant. These worms include armyworm, beet armyworm, autumn armyworm, melon worms, pickle worms, tomato hornworm, love apple pinworm, yellow striped armyworm and the corn ear worm, or the tomato fruit worm.

Plants Attacked: Sweet corn, beans, peas, beets, peppers, melons, squash, cucumber, cauliflower, broccoli and similar crops. The description of these diverse insect larvae is completely different. Many have elongate bodies, may exist striped with spots, and most of them are dark-green to brown to reddish colour. The stripes may exist white or yellow. About all of them have three legs behind the head and five sets of legs along the abdomen.

Life History: Many spend the wintertime as pupae two to 6 inches below the soil surface and sally as moths during the spring and early on summer to brainstorm depositing eggs on their favorite crops or host establish. Fresh laid eggs normally are waxy white, just soon turn yellow and darker as the insect matures inside. They are about half the size of a pinhead and variously shaped. A female person tin can deposit from 500 to 3,000 eggs singly on leafage and fruit of many plants. They prefer the tender growing bespeak of the plant to deposit eggs, but eggs usually are deposited in the curl of various plants and in the whirl of corn or grassy crops. Later in the season, they may deposit eggs directly on the fruit of the found. The eggs unremarkably hatch in 2 to 4 days, but it may take up to ten days in cold conditions; the worm stage lasts 2 to 4 weeks. Full grown larvae crawl downward the host plant or drop to the basis when they burrow forming a wall shell cell and pupate. The adult moths usually sally in x to 25 days following pupation. Time from egg to adult varies from 1 to 2 months depending upon weather weather. There may be 4 to vii generations of these various worms throughout the yr.

Impairment: Newly hatched larvae begin feeding immediately on the office of the found where the eggs were laid. They may and then bore into the fruit such as tomatoes or the ears of corn or feed on pods of beans and peas. The worms cause considerable harm because they gnaw or eat out sections of the fruit, and may cause the fruit to rot.

Cabbage Looper

Plants attacked: Cabbage, cauliflower, broccoli, Brussels sprouts, lettuce and occasionally beans, tomatoes and other crops.

Clarification: Calorie-free, grayish brown moth with a small lighter colored spot nigh center of forewings. Moths take a fly spread of about i½ inch. Larvae are light green caterpillars with a few white or stake yellow stripes. Larvae travel with a characteristic looping motion. They have three legs backside the head and three legs at the tip of the abdomen.

Life History: There are continuous generations in the Lower Rio Grande Valley with reproduction slowing down during common cold periods. In colder areas the insects overwinter as pupae in flimsy silken cocoons attached to plant residue. A complete generation occurs in 3 to half-dozen weeks.

Damage: Cabbage loopers are voracious feeders which can strip foliage from infested plants in a short fourth dimension. Oft, when cabbage looper populations become crowded, a virus disease strikes causing high larval mortality.

Thrips

Plants Attacked: General feeders on vegetables, flowers and field crops.

Description: These are slender, spindle shaped, active insects varying from stake xanthous to yellowish-brown. Adults average well-nigh 1/25 inch long. Four slender wings are present on females, fringed with long hairs and blackness margins. Males are wingless, and the larvae resemble adults but accept no wings and are smaller.

Life History: The minute eggs are inserted into leaves or stems. These hatch in 2 to 10 days. The larval stage lasts from five to 30 days. Developed females can reproduce regularly without mating with the rarely found males. All stages can be found during warmer months, but during colder months, but adults and larvae can be institute. It is likely that 5 to 8 generations occur per year, but more may occur in the warmer parts of the state.

Damage: Thrips puncture plants, rasp the surface and then suck the juice. This causes the germination of whitish blotches that first appear as dashes. Severely attacked plants develop a gray or silver appearance and may become distorted. Damage may be found start in the leaf sheaths and stems or in the undersides of a bent leaf where the insects e'er are most abundant.

Sucking Insects

Aphids

Aphids are small, sluggish soft-bodied insects often called plant lice. Most species give birth to living young and the young build upward very rapidly.

Plants Attacked: All vegetables. About mutual vegetables are peas, beans, tomatoes, lettuce, turnips, broccoli and corn.

Description: The well-nigh mutual aphids are the melon or cotton aphid, light-green peach aphid, cabbage aphid and the pea aphid. They are usually 1/sixteen inch long, soft-bodied and pear-shaped. They may be black, grayness, green, red or yellowish, depending on the species.

Life History: Most species requite birth to living young; they do lay eggs, and some have wings. There can be fifteen to 20 generations per year of certain species.

Damage: Aphids congregate in big numbers and, therefore, may infest vegetables such equally mustard greens and leaf lettuce; they also may cause the plant to stunt. Disease manual is probably more important than actual feeding damage.

Squash Bugs

Plants Attacked: All cucurbits with preference for squash.

Description: The adults are brownish gray to night gray bugs about 5/8 inch long. The young, or nymphs, when first hatched are green with black legs. Later, they become grayish-white with nigh blackness legs and antennae.

Life History: Adults overwinter, unmated in any type of shelter. They appear in the bound as plants begin to vine and mate. Yellowish to bronze-brown eggs are laid in clusters on the underside of leaves usually in vine angles. Eggs hatch in 1to 2 weeks, and nymphs feed in groups on the stems of the plant for 6 to 8 weeks earlier transforming to adults.

Damage: Leaves attacked past the squash bug will quickly become black, crisp and dead. Attacked found stems often are enlarged but later wither and die.

Stink Bugs

Plants Attacked: Seed beets, okra, squash, beans, peas, corn, cowpeas, and tomatoes.

Description: The adults are approximately ½ inch long, and each has a triangular shaped shield on the back that extends merely back of the shoulders narrowing posterior to a point. Front wings are thickened and stiff about the base, merely the distal half is much thinner and bleary. Crushed bugs ofttimes accept an odor fitting their proper noun. The nymphs are without fly covers and smaller just otherwise like to adults.

Life History: Life history and habits of each of the stink bugs are similar. Generally butt shaped eggs are deposited in clusters usually on the underside of foliage. Eggs often are beautifully colored and ornamental. Development from egg to adult occurs in 4 to six weeks. From i to iii or perhaps four generations may occur annually. They overwinter as adults in places affording protection from cold conditions.

Damage: Damage is acquired by nymphs and adults sucking sap primarily from pods, buds, blossoms and seeds. In removing the liquid from contents of developing seeds causes them to become flattened and shriveled. If the pods are attacked at an early phase of evolution, catfacing or pitted holes volition occur on edible bean pods and squash fruit.

Whiteflies

Plants Attacked: Tater, tomato, eggplant, pepper and sweetness potato.

Clarification: Adults are 1/16 inch in length. They have four wings which along with the dorsal part of the body are covered with white, waxy powder. The nymphs are light dark-green, oval, flattened and about the size of a pinhead. They are attached to the foliage surface until mature, with the last instar more elevated and slightly segmented. The bodies are covered with radiating long filamentous threads resembling young, soft calibration insects.

Life History: Overlapping generations occur in the Lower Rio Grande Valley during jump, summer and fall. Adults emerge, mate and brainstorm depositing elongated yellow eggs and attaching them to the host plant past brusque stalk. Before hatching, the eggs darken; nymphal period is one month.

Damage: Both nymphs and adults feed past sucking institute juices. Heavy feeding gives plants a mottled advent, or it causes them to turn xanthous and die. The sticky honeydew excreted by the insect often glazes the lower leaves and permits development of black sooty mold on plants, thus detracting from the plant'south beauty and cutting down on photosynthesis.

Spider Mites

Plants Attacked: Various plants are attacked including tomatoes, eggplants, beans, corn, peas and various cucurbits.

Clarification: The two-spotted spider mite has two forms, a green class with a dark spot on each side and the more common which is a reddish form. Some species of mites may be yellow. All mites are very tiny and nigh microscopic. They are near 1/60 inch long. Life History: Adult mites lay eggs on leaf undersides and spin webs beneath which eggs hatch and mites feed. Spider mites reproduce rapidly during hot, dry weather condition.

Damage: Mites pierce leafage tissue and suck sap in the larval, nymphal and adult stages. Plants attacked begin to lose colour, fading from green to yellow and somewhen plough red. Heavy infestation may kill some plants, and heavy webbing may appear on certain plants.

The following table is courtesy of S.Due east. Webb and P.A. Stansly at Academy of Florida, IFAS Extension Publication ENY-419 titled 'Insecticides Currently Used on Vegetables'.

Table one.

Insecticides For Use On Vegetables

Insecticide	Full general Characteristics	Signal Word	MOA1	Typical Target Pests
Carbamates
*Furadan(carbofuran)	systemic action	Danger-Poison	1A	beetles, some caterpillars
*Lannate(methomyl)	very short balance	Danger-Poison	1A	caterpillars, leafhoppers
Larvin(thiocarb)	larvacide & ovicide	Warning	1A	caterpillars
Sevin(carbaryl)	apply can result in aphid and mite outbreaks	Caution – 4F, XLR, Bait; Warning – 80S	1A	beetles, leafhoppers, caterpillars
*Temik(aldicarb)	systemic action	Danger-Poisonous substance	1A	aphids, mites, some beetles
*Vydate(oxamyl)	contact activity, systemic if practical to soil	Danger-Poison	1A	aphids, thrips, some beetles
Organophosphates
*Counter(terbufos)	systemic action	Danger-Poisonous substance	1B	soil pests
*Diazinon		Caution	1B	aphids, beetles, caterpillars, soil pests, thrips
Dibrom(naled)	some brusque residual fumigant action	Danger	1B	caterpillars
Dimethoate	local systemic	Warning	1B	aphids, leafhoppers, mites
*Di-Syston(disulfoton)	systemic activity	Danger-Poison	1B	aphids
Imidan(phosmet)		Alert	1B	caterpillars, sweetpotato weevil
Lorsban(chlorpyrifos)	long residual	Caution – 15GWarning – 75WG, *4E Danger – 50W	1B	caterpillars, soil pests
Malathion	short residual	Alarm	1B	broad spectrum
*MSR Spray Concentrate (oxydemetonmethyl)	systemic; contact & tummy action	Alert	1B	aphids, thrips & other sucking insects
*Mocap(ethoprop)	contact activeness	Danger-Poison	1B	aphids, caterpillars
*Monitor(methamidophos)	long residual	Danger-Toxicant	1B	aphids, caterpillars & other pests
*Penncap-M(methyl parathion)	contact & fumigant action; slow release formulation	Warning	1B	caterpillars, thrips
*Thimet(phorate)	systemic action	Danger-Poison	1B	soil pests, thrips
Organochlorines
*Endosulfan(endosulfan)	fairly long residual	Danger-Toxicant	2A	aphids, beetles, caterpillars, whiteflies
Pyrethroids
*Deadfall(permethrin)		Alarm	3	beetles, caterpillars, leafhoppers, thrips
*Ammo(cypermethrin)		Caution	3	beetles, caterpillars, leafhoppers, thrips
*Asana(esfenvalerate)		Warning	3	beetles, caterpillars, leafhoppers
*Baythroid XL(beta-cyfluthrin)		Warning	iii	beetles, caterpillars, leafhoppers, thrips
*Brigade(bifenthrin)		Alarm	three	beetles, caterpillars, leafhoppers, thrips, whiteflies
*Danitol(fenpropathrin)		Danger	iii	caterpillars, leafhoppers, whiteflies
*Strength(tefluthrin)		Caution	3	soil pests
*Mustang Max (zeta-cypermethrin)		Alarm	three	beetles, caterpillars, leafhoppers, thrips
*Pounce(permethrin)		Caution -(3.2EC, ane.5G) Alert – (25WP, WSP)	3	beetles, caterpillars, leafhoppers, thrips
*Proaxis(gamma-cyhalothrin)		Circumspection	3	beetles, caterpillars, leafhoppers, plant bugs, stink bugs
Pyronyl Crop Spray (Pyrethrins)	contact, stomach, & fumigant action; extract from chyrsanthemums	Caution	iii	broad spectrum
*Warrior (lambda-cyhalothrin)		Warning	3	beetles, caterpillars, leafhoppers, thrips
Neonicotinyls
Actara(thiamethoxam)	local systemic	Caution	4A	aphids, potato leafhopper, some beetles, stinkbugs, whiteflies
Admire(imidacloprid)	systemic, long residual	Caution	4A	aphids, leafhoppers, some beetles, whiteflies
Set on(acetamiprid)	local systemic, ovicidal effects	Caution	4A	aphids, Colorado potato protrude, whiteflies
Belay(clothianidin)	systemic, long residual	Caution	4A	Colorado potato beetle, aphids, leafhoppers
Platinum (thiamethoxam)	systemic, long residual	Caution	4A	aphids, irish potato leafhopper, some beetles, stinkbugs, whiteflies
Provado(imidacloprid)	local systemic	Caution	4A	aphids, leafhoppers, some beetles, whiteflies
Venom(dinotefuran)	systemic or locally systemic, depending on application method, long residual	Circumspection	4A	aphids, Colorado potato beetle, leafhoppers, leafminers, thrips, whiteflies
Other insect nerve poisons
Acramite(bifenazate)	contact, long remainder, ovicidal activeness against spider mites	Circumspection	united nations	mites
*Agri-Mek(abamectin)	active once ingested; some contact action; mostly stomach poison	Warning	6	leafminers, mites, some beetles, tomato pinworm
Avaunt(indoxacarb)	ingestion plus contact, slightly to moderately translaminar	Circumspection	22	caterpillars
Beleaf(flonicamid)	contact & ingestion, causes rapid abeyance of feeding	Caution	9C	aphids
Coragen(rynaxypyr)	long residuum, causes rapid cessation of feeding	None	28	caterpillars, Colorado murphy protrude, leafminers
Fulfill(pymetrozine)	feeding inhibitor	Caution	9B	aphids, whiteflies
*Proclaim(emamectin benzoate)	ingestion & topical; translaminar, not systemic	Caution	6	caterpillars
Radiant(spinetoram)	ingestion & contact; enters leafage but does not translocate	Caution	5	caterpillars, some beetles and thrips
SpinTor(spinosad)	ingestion & contact; enters leafage simply does not translocate	Caution	five	caterpillars, some beetles and thrips
Insect Growth Regulators
Ostend(tebufenozide)	wearisome interim	Caution	18	caterpillars
Courier(buprofezin)	disrupts egg hatch and molting; use in rotation iwth other insecticides	Caution	16	whiteflies
*Dimilin(diflubenzuron)	slow interim, disrupts molting process, reduces egg hatch of pepper weevil	Caution	fifteen	caterpillars, pepper weevil
Esteem Pismire Bait(pyriproxyfen)	breaks reproductive cycle of ants; slow acting but constructive	Circumspection	7C	ants
Extinguish[(S)-methoprene]	ho-hum acting	Circumspection	7A	fire ants
Intrepid(methoxyfenozide)		Caution	18	caterpillars
Knack(pyriproxyfen)	use in combination or rotation with other insecticides	Circumspection	7C	whiteflies
Neemix(azadirachtin)	slow interim, also acts as feeding repellent	Caution – Azatin 40 Plus; Alert – Neemix 4.5	un	broad spectrum
Rimon(novaluron)	disrupts cuticle formation and deposition at molting, resulting in death of larva; no effect on developed insect	Warning	15	caterpillars
Trigard(cyromazine)	nearly constructive against modest leafminer larvae	Circumspection	17	dipterous leafminers, maggots, some beetles
Miscellaneous
Bacillus thuringiensis(B.t.) var. aizawai (B.t.) var. kurstaki	pest must ingest; slow interim just feeding stops long before death	Caution	11	caterpillars or beetles, depending on strain
Cryolite(Kryocide)	pest must ingest; not rainfast; an inorganic fluorine compound	Circumspection	united nations	beetles, caterpillars
Thou-Pede(potassium salts of fatty acids)	contact activity; phytotoxic at high temperatures	Alarm		aphids and other soft-bodied arthropods
Movento(spirotetramat)	ingestion, fully systemic in plant after foliar application	Caution	23	aphids, psyllids, whiteflies
Mycotrol(Beauveria)	contact; ho-hum acting		—	aphids, leafhoppers, whiteflies
Oberon(spiromesifen)	inhibitor of lipid synthesis; about effective on juvenile stages of mites and on nymphs and pupae of whiteflies and psyllids	Caution	23	mites, psyllids, whiteflies
SunSpray Ultra Fine Spray Oil(mineral oil)	contact activeness	Circumspection	—	aphids, mites, whiteflies
M-Pede(potassium salts of fatty acids)	contact activity; phytotoxic at high temperatures	Warning	—	aphids and other soft-bodied arthropods
*Vendex (fenbutatin-oxide)		Danger-Poisonous substance	12B	mites
*Restricted Use PesticideOriginally adapted from: Welty, Celeste. Insecticides for use on vegetables in Ohio. pp. 46-48, 2002 Ohio Vegetable product Guide, Ohio State University. 1Mode of Activity codes for vegetable pest insecticides from the Insecticide Resistance Action group (IRAC) Way of Activeness Classification v.3.3 October 2003. 1A. Acetylcholinesterase inhibitors, Carbamates (nerve action) 1B. Acetylcholinesterase inhibitors, Organophosphates (nervus activity) 2A. GABA-gated chloride channel antagonists (nerve action) three. Sodium channel modulators 4A. Nicotinic acetylcholine receptor agonists (nervus action) v. Nicotinic acetylcholine receptor allosteric activators (nerve action) 6. Chloride aqueduct activators (nerve and muscle activity) 7A. Juvenile hormone mimics (growth regulation) 7C. Juvenile hormone mimics (growth regulation) 9B & 9C. Selective homopteran feeding blockers 10. Mite growth inhibitors (growth regulation) 11. Microbial disruptors of insect midgut membranes 12B. Inhibitors of mitochondrial ATP synthase (energy metabolism) 15. Inhibitors of chitin biosynthesis, blazon 0, lepidopteran (growth regulation) 16. Inhibitors of chitin biosynthesis, type 1, homopteran (growth regulation) 17. Molting disruptor, dipteran (growth regulation) 18. Ecdysone receptor agonists (growth regulation) 22. Voltage-dependent sodium aqueduct blockers (nerve action) 23. Inhibitors of acetyl Co-A carboxylase (lipid synthesis, growth regulation) 28. Ryanodine receptor modulators (nerve and muscle action) un. Compounds of unknown or uncertain mode of activeness

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Source: https://aggie-horticulture.tamu.edu/vegetable/guides/texas-vegetable-growers-handbook/chapter-vi-insect-management/

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