Chemical method of pest control: Different types of chemicals are used for the control of insect pests. Insecticides can be grouped in various ways, such as their chemical composition, mode of entry, and formulations in which they are to be applied.
Chemical method of pest control
Chemically, the types of insecticides are;
1. Elements such as s.p.
2. Inorganic compounds such as lead, arsenate, zinc, and phosphide.
3. Organic compounds.
- Compounds of plant origin include pyrethrum, nicotine, neem oil, and fugenol.
- Animals and mineral oils-such as fish oil and diesel oil.
- Synthetic organic compounds- malathion, Diazinon.
- Poisonous gases- Ethyl bromide, Ethylene dichloride(ED), Carbon Tetrachloride
According to their mode of entry, insecticides can be grouped into-
- Stomach poison
- Contact poison
- Systemic
- Fumigants
Stomach poison: They are generally applied against insects with chewing-type mouthpart. These are also mixed with food to kill higher animals like rodents and birds. Stomach poisons are applied as spray dust on baits.
Contact poison: A toxicants-which kills the insect by contact and enters the insects through vulnerable sites, is said as contact poison applied as dust spray directly to the insects’ body or the places frequented by them. This type of poison is particularly effective for the control of sucking insects.
Systemic poison: A systemic insecticide, when applied to seeds, roots, stems, or leaves of plants, is absorbed and translocated to various parts of the plants in amounts lethal to insects that feed on them. Most systemic insecticides act both as stomach & contact poisons. Granular systemic insecticides are most effective and favorable to our farmers.
Fumigants: Poisonous gases are used as fumigants to kill insect pests of stored grain and products in warehouses, elevators, godawns, etc. The toxicant enters the trachea of the insets through the spiracles in the form of gas and brings about its kill. Since all fumigants are deadly poisonous, great care is in their use. All phosphide, CH3Br.
Miscellaneous chemicals:
Nowadays, in addition to the use of insecticides for controlling insect pests, various chemicals with various types of action are also being used for controlling insect pests.
a) Chemo-sterilant: Apholate, tepa, and metepa are fed to the insects along with foods & through their physiological action, they cause sterility, and ultimately the pest population declines.
b) Anti-feedants: Anti-feedants, when spread on plants and mixed with foods, make them distasteful, and the insect does not feed and ultimately starves death. Recently, a systemic antifeedant called Baygon (methylcarbamate) has been an effective agent against the cotton ball weevil.
c) Alteractants: Attractants are used when insects are poisoned through baits. Many attractants occur naturally either in the food or as pheromones that are secreted or released by other members of the same species, promoting aggregation and mating other types of behavior. The synthetic pheromone glare related to the natural compound of the gypsy moth has become important in insect control work.
Regulatory method
- Legislation for foreign quarantine to prevent new pests from abroad.
- Legislation for domestic quarantine prevents the spread of established pests within the country or in particular zones/states.
- Legislation for notified campaigns to control insect pests.
- Legislation prevents the adulteration and mishandling of insecticides or other devices used to control pests.