Cultural controls are selected used preventively and selected according to the chances of particular insect problems occurring in the area. Another important concept is that it often takes a large number of a particular pest to reduce the yield of a plants and affect plant health. A single aphid should not cause alarm, but many colonies on just a few plants may require action. In this instance, a strong stream of water or an application of insecticidal soap may be all that is needed.
This publication lists some of the various general use insecticides that are currently on the market for home gardeners.
The usage area for a particular insecticide are indicated, but the user must check each label to be sure that application to particular types of plants are permitted. Only the uses listed on the pesticide label are permitted. You must read the labels to understand the restrictions. Another label restriction is the minimum amount of time between application and when food crops can be harvested. This is referred to as the pre-harvest interval PHI. Other information concerning mixing and dosages, application methods, protective equipment, storage, and container disposal are also included on the label.
It is a selective contact insecticide and miticide, also effective against thrips, aphids, whiteflies and leafhopprs. Registrations are for pome fruits, almonds, citrus, ornamentals and greenhouse ornamentals.
Pyridaben provides exceptionally long residual control, and rapid knockdown at a broad range of temperatures. Mode of action Pyridaben is a metabolic inhibitor that interrupts mitochondrial electron transport at Site 1, similar to the Quinazolines, below. Fenazaquin is a contact and stomach miticide. It has ovicidal activity, gives rapid knockdown, and controls all stages of mites. Not yet registered in the U.
Mode of action Fenazaquin inhibits mitochondrial electron transport at Site 1, similar to the Pyridazinones, above. Benzoylureas are an entirely different class of insecticides that act as insect growth regulators IGRs. Rather than being the typical poisons that attack the insect nervous system, they interfere with chitin synthesis and are taken up more by ingestion than by contact.
Their greatest value is in the control of caterpillars and beetle larvae.
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Benzoylureas were first used in Central America in , to control a severe, resistant leafworm complex Spodoptera spp. The withdrawal of the ovicide chlordimeform made their control quite difficult due to their high resistance to almost all insecticide classes, including the pyrethroids. Among the newer benzoylureas only hexaflumuron and novaluron have been registered by EPA. The only other benzoylurea registered in the U. It was first registered in for gypsy moth, cotton boll weevil, most forest caterpillars, soybean caterpillars, and mushroom flies, but now with a much broader range of registrations.
It is selective toward Dipterous species and used for the control of leafminers in vegetable crops and ornamentals, and fed to poultry or sprayed to control flies in manure of broiler and egg producing operations, and incorporated into compost of mushroom houses for fungus gnats. Mode of action The benzoylureas act on the larval stages of most insects by inhibiting or blocking the synthesis of chitin, a vital and almost indestructible part of the insect exoskeleton.
Typical effects on developing larvae are the rupture of malformed cuticle or death by starvation. Adult female boll weevils exposed to diflubenzuron lay eggs that do not hatch. And, mosquito larvae control can be achieved with as little as 1. Botanical insecticides are of great interest to many, for they are natural insecticides, toxicants derived from plants. Historically, the plant materials have been in use longer than any other group, with the possible exception of sulfur.
Tobacco, pyrethrum, derris, hellebore, quassia, camphor, and turpentine were some of the more important plant products in use before the organized search for insecticides began in the early s. In recent years the term biorational has been put into play by the EPA. There are similarities and differences between the terms botanical and biorational. We include a section on the biorationals below and will address the overlaps in that section. Botanical insecticide use in the U.
Pyrethrum is now the only classical botanical of significance in use. Some newer plant-derived insecticides that have come into use are referred to as florals or scented plant chemicals and include, among others, limonene, cinnamaldehyde and eugenol. In addition, there is azadirachtin from the neem tree which is used in greenhouse and on ornamentals.
Pyrethrum is extracted from the flowers of a chrysanthemum grown in Kenya and Ecuador. It is one of the oldest and safest insecticides available. The ground, dried flowers were used in the early 19th century as the original louse powder to control body lice in the Napoleonic Wars. Pyrethrum acts on insects with phenomenal speed causing immediate paralysis, thus its popularity in fast knockdown household aerosols.
However, unless it is formulated with one of the synergists , most of the paralyzed insects recover to once again become pests.
Mode of action Pyrethrum is an axonic poison, as are the synthetic pyrethroids and DDT. Axonic poisons are those that in some way affect the electrical impulse transmission along the axons, the elongated extensions of the neuron cell body. Pyrethrum and some pyrethroids have a greater insecticidal effect when the temperature is lowered, a negative temperature coefficient, as does DDT. They affect both the peripheral and central nervous system of the insect. Pyrethrum initially stimulates nerve cells to produce repetitive discharges, leading eventually to paralysis.
These effects are produced in insect nerve cord, which contains ganglia and synapses, as well as in giant nerve fiber axons. Nicotine is extracted by several methods from tobacco, and is effective against most all types of insect pests, but is used particularly for aphids and caterpillars--soft bodied insects. Nicotine is an alkaloid, a chemical class of heterocyclic compounds containing nitrogen and having prominent physiological properties.
Other well-known alkaloids that are not insecticides are caffeine coffee, tea , quinine cinchona bark , morphine opium poppy , cocaine coca leaves , ricinine a poison in castor oil beans , strychnine Strychnos nux vomica , coniine spotted hemlock, the poison used by Socrates , and, finally LSD a hallucinogen from the ergot fungus attacking grain. Mode of action Nicotine action is one of the first, classic modes of action identified by pharmacologists. Drugs that act similarly to nicotine are said to have a nicotinic response.
In insects the same action is observed, but only in the central nervous system ganglia. It is both a stomach and contact insecticide and used for the last century and a half to control leaf-eating caterpillars, and three centuries prior to that in South America to paralyze fish, causing them to surface and be easily captured. Today, rotenone is used in the same way to reclaim lakes for game fishing. Used on a prescribed basis, it eliminates all fish, closing the lake to reintroduction of rough species.
Description of the application method in technical and scientific work on insecticides
It is a selective piscicide in that it kills all fish at dosages that are relatively nontoxic to fish food organisms, and is degraded rapidly. Limonene or d -Limonene is the latest addition to the botanicals. Limonene belongs to a group often called florals or scented plant chemicals. Extracted from citrus peel, it is effective against all external pests of pets, including fleas, lice, mites, and ticks, and is virtually nontoxic to warm-blooded animals.
Two other recently introduced floral products are eugenol Oil of Cloves and cinnamaldehyde derived from Ceylon and Chinese cinnamon oils. They are used on ornamentals and many crops to control various insects. Mode of action Its mode of action is similar to that of pyrethrum. It affects the sensory nerves of the peripheral nervous system, but it is not a ChE inhibitor.
- Insecticides: Basic And Other Applications.
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- Insecticides Basic And Other Applications 2012.
- Insecticides Basic And Other Applications 2012.
- An Introduction to Insecticides (4th edition)?
Neem oil extracts are squeezed from the seeds of the neem tree and contain the active ingredient azadirachtin , a nortriterpenoid belonging to the lemonoids. Azadirachtin has shown some rather sensational insecticidal, fungicidal and bactericidal properties, including insect growth regulating qualities. Mode of action Azadirachtin disrupts molting by inhibiting biosynthesis or metabolism of ecdysone, the juvenile molting hormone. Synergists are not in themselves considered toxic or insecticidal, but are materials used with insecticides to synergize or enhance the activity of the insecticides.
The first was introduced in to increase the effectiveness of pyrethrum. Since then many materials have appeared, but only a few are still marketed. Synergists are found in most all household, livestock and pet aerosols to enhance the action of the fast knockdown insecticides pyrethrum, allethrin, and resmethrin, against flying insects.
Current synergists, such as piperonyl butoxide, contain the methylenedioxyphenyl moiety, a molecule found in sesame oil and later named sesamin. Mode of action The synergists inhibit cytochrome P dependent polysubstrate monooxygenases PSMOs , enzymes produced by microsomes, the subcellular units found in the liver of mammals and in some insect tissues e. The earlier name for these enzymes was mixed-function oxidases MFOs.
These PSMOs bind the enzymes that degrade selected foreign substances, such as pyrethrum, allethrin, resmethrin or any other synergized compound. Synergists simply bind the oxidative enzymes and prevent them from degrading the toxicant.
In this category belong the avermectins , which are insecticidal, acaricidal, and antihelminthic agents that have been isolated from the fermentation products of Streptomyces avermitilis , a member of the actinomycete family. The most promising uses for these materials are the control of spider mites, leafminers and other difficult-to-control greenhouse pests, and internal parasites of domestic animals. It was first registered in It is both a stomach and contact insecticide used primarily for control of caterpillars at the rate of 0.
Shortly after exposure, larvae stop feeding and become irreversibly paralyzed, dying in days. Rapid photodegradation of both abamectin and emamectin occurs on the leaf surface.
Mode of action Avermectins block the neurotransmitter g-aminobutyric acid GABA at the neuromuscular junction in insects and mites. Visible activity, such as feeding and egg laying, stops shortly after exposure, though death may not occur for several days. They are usually heavier than air and commonly contain one or more of the halogens Cl, Br, or F. Most are highly penetrating, reaching through large masses of material. They are used to kill insects, insect eggs, nematodes, and certain microorganisms in buildings, warehouses, grain elevators, soils, and greenhouses and in packaged products such as dried fruits, beans, grain, and breakfast cereals.