What Are Insecticides Made Of?
Insecticides are toxic substances that are used to kill insects. They can be used by humans who may be working outside to prevent insect bites and contact, but they are primarily used to protect plants and eliminate insects that carry disease. This article will look at what insecticides are made of and how they are classified.
Modes of Penetration
Insecticides can be classified in the way they are penetrated by insects. They can be ingested, inhaled or work upon contact. Insecticides that are ingested are stomach toxins and can only be effective if they are ingested through the mouth. Therefore, they are most effective on insects that can bite or chew, like caterpillars, beetles and grasshoppers. The chief stomach poisons are arsenicals including Paris green (copper acetoarsenite), lead and calcium arsenate, and fluoride compounds like sodium fluoride and cryolite. They are applied as sprays or dusts to the leaves and stems of plants. Stomach poison insecticides have gradually been replaced by synthetic, organic insecticides which are less harmful to humans and other animals.
Contact poisons work by penetrating the insect’s skin. They are effective against arthropods that pierce the skin of a plant and suck out the juices. They can be naturally occurring or synthetic organic compounds. Naturally occurring compounds include nicotine, which is developed from tobacco; pyrethrum, which is obtained from flowers; Derris which is developed from plants; and oils which are derived from petroleum. Although these contact poisons are derived naturally, the toxic agents are usually synthesized. They also are generally short lived, and can not protect against prolonged invasions. Though pyrethrum is still commonly used, most of these have been replaced by newer synthetic organic insecticides.
Fumigants work by entering the respiratory system through the pest’s breathing openings. They include chemicals like hydrogen cyanide, naphthalene, nicotine and methyl bromide. They are mainly used for killing pests that feast on stored products or for fumigating nurseries.
What Synthetic Insecticides Are Made Of
As stated above, many of the chemicals in insecticides used in the past have been replaced by synthetic insecticides. The main synthetic groups are as follows:
Chlorinated Hydrocarbons: While we do not fully understand the toxic action of chlorinated hydrocarbons, we know that they primarily work by disrupting the insect’s nervous system. They were developed at the beginning of the 1940’s after the discovery of the insecticidal properties of DDT. Examples of the hydrocarbons include BHC, lindane, Chlorobenzilate, methoxychlor and cyclodienes. Some of these compounds are stable and can last for long periods of time.
Organophosphates: These work by inhibiting the enzyme cholinesterase, which is essential to the functioning of the insect’s nervous system. They are the largest and most versatile of the insecticides. The most common types of these are the compounds parathion and malathion while others include Diazinon, naled, methyl, parathion and dichlorvos. They are most effective against sucking insects like aphids and mites which feed on plant juices. They are used by applying the solution to the soil which is then penetrated through the plant’s roots. They are generally more toxic than chlorinated hydrocarbons.
Carbamates: These are a newer group of insecticides that work to kill insects in a way that is similar to that of the organophosphates. They are rapidly detoxified and eliminated from animal tissues. Compounds include carbamyl, methomyl and carbofuran.
Pros and Cons of Insecticides
Since synthetic insecticides have come into play in the mid 20th century, it has made the control of insects and other pests much more effective. Despite environmental drawbacks, they are still often used in modern agriculture and help to prevent crop losses, raise the quality of produce, lower the cost of farming and increase crop yields by up to 50%. They have also worked to reduce the risks of infectious diseases like malaria, yellow fever and typhus in humans and animals.
However, there are a number of downsides to the use of these insecticides. One of these disadvantages includes the fact that they pose a threat to the environment. Many insecticides are short lived and are metabolized by the animals that ingest them, but others are more persistent and can be damaging when applied in large amounts. If it reaches the soil or groundwater, it can cause contamination which can occur due to direct application or run off by treated areas. Harmful contaminants include DDT, aldrin, dieldrin, heptachlor and BHC.
When insecticides are sprayed often it can begin accumulating in the soil in surprisingly large amounts. This begins to effect wildlife and its food chains, builiding up in bodily tissues. Birds of prey are most severely effected and declines in their populations have been traced to the use of DDT. Because of this, the chemical was restricted in the 1960’s and later banned in the 70’s.
Another downside in the use of insecticide is that pests are likely to form a resistance to its effects. Members of a population are killed off but the resistant strains that survive multiply and can be carried on in a majority of the species. This makes for an increased number of insects that can not be controlled by the recommended rate for usage. Once resistance is formed to one insecticide, it may also be formed to others that have similar modes of action.
Once developed, resistance can last for any amount of time, depending on the type of resistance and the species of the pest. It can also work to encourage the growth of the insect population by eliminating natural enemies that once kept them in check. The nonspecific nature of the broad spectrum chemicals makes it likely they have unintended effects on many insects that can be harmful or beneficial.
Due to the fact that there are so many issues associated with the use of insecticides, a method called integrated control was introduced. In this method, a minimal amount of the insecticide is used with different pest resistant crop varieties. Crops are also raised in such a way that they inhibit pest proliferation. Organisms that are predators or parasites of the pests are released and sterilization is used to control the pest’s reproduction.
Southern Ag Natural 8-Ounce Concentrate: If you are looking for an insecticide that is eco-friendly and can control and eliminate a wide range of insects, Southern Ag is a great choice. It is effective on fruits and vegetables as well as pets and livestock and can also control infestations in the house. Containing 96% Pyrethrin, it is tough on pests but kind to your plants.
CRC Industries 14010 Wasp and Hornet Killer 14 oz. Aerosol Can with Trigger Clear Plus: Those who require protection from pests that bother them while they are working outdoors on sensitive equipment, this insect killer is recommended. It contains distillates and it hydro-treated 64742-47-8 light carbon dioxide, tetramethrin and d-phenothrin. It is a clear liquid that can kill wasps, hornets and many other insects. It comes in a 14 oz. aerosol can with a trigger that can easily control the insecticide. It is great for any outdoor worker who works with electric and power utilities, telecommunications equipment and installation sites, bridge and tower maintenance, cable and wire installation sites, industrial plant grounds, warehouses, farm structures and buildings.
There is a bit of controversy regarding what insecticides are made of as far as whether they are environmentally safe. However, despite the disadvantages that may be associated with use, insecticides are necessary to protect humans, plants and crops from the damage pests can cause. Upgrades are constantly being made so that insecticides can be used safely in the agriculture and service industries. In the meantime, they are still an effective way to control pests that may be harmful to your well being.