Insects And Spiders As Pests

Insects are humanity's greatest competitors and cause huge economic losses when they feed on timber, stored foods, pastures, and crops. Termites and other insects infest and weaken wood used to build homes, businesses, floors, cabinets, and furniture. The larvae of clothes moths and carpet beetles destroy woolen clothing, rugs, and hides. Mites, moths, beetles, and other insects invade homes and infest stored foods and destroy books and other paper products. Crops lost to insect damage cause enormous economic hardship and may lead to starvation and death among hundreds or thousands of people. One-third to one-half of all food grown worldwide is lost to damage caused by insects and mites, not only by devouring the foliage but also by infecting plants with diseases.

Arthropods not only eat people's belongings, they also attack human bodies. The bites of blood-feeding mosquitoes, flies, fleas, lice, and ticks are not only irritating, they are also responsible for spreading diseases that can infect and kill people, pets, and farm animals. Over the centuries more people have died from diseases carried by arthropods than any other reason. Even today, more people die from malaria and yellow fever, diseases transmitted by mosquitoes, than from HIV/AIDS, cancer, accidents, and wars. Spiders, millipedes, centipedes, and other arthropods are not often pests but are considered nuisances when they enter homes. The venomous bites of some spiders and centipedes may be painful but are seldom life-threatening for healthy adults.

These and other pests are effectively controlled by integrated pest management, or IPM. IPM includes plowing fields to kill pests in the ground, rotating crops so that they will not have anything to eat, or planting other crops nearby that will give their enemies a place to live and prosper. Whenever possible, natural enemies are used to combat pests instead of pesticides. The use of predators, parasitoids, and diseases is called biological control. Spiders might be considered biological controls in some fields, but most species tend to eat anything they can catch, not just the pest. IPM depends on accurate identification of the pest and a thorough knowledge of its life history so that control efforts can be directed at the pest's most vulnerable life stages. However, if not used wisely, any pest control method may harm other species or their habitats.

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