By the 1960s, problems of resistance to chemicals and damage to the environment began to emerge, and biological control had a renaissance. The introduction of DDT, a cheap and effective compound, put an effective stop to biological control experiments. In the 1880s, ladybirds were used in citrus plantations in California to control scale insects, and other biological control experiments followed. In 1762, an Indian mynah was brought to Mauritius to control locusts, and about the same time, citrus trees in Burma were connected by bamboos to allow ants to pass between them and help control caterpillars. Also around 4000 BC in China, ducks were used in paddy fields to consume pests, as illustrated in ancient cave art. Biological control is first recorded around 300 AD in China, when colonies of weaver ants, Oecophylla smaragdina, were intentionally placed in citrus plantations to control beetles and caterpillars. The harmful side effect of pesticides on humans has now resulted in the development of newer approaches, such as the use of biological control to eliminate the ability of pests to reproduce or to modify their behavior to make them less troublesome. In the 20th century, the discovery of several synthetic insecticides, such as DDT, and herbicides boosted this development. With the industrialisation and mechanization of agriculture in the 18th and 19th centuries, and the introduction of the insecticides pyrethrum and derris, chemical pest control became widespread. This led the way to a widespread acceptance of insecticides across the continent. After much discussion, arsenical compounds were used to control the beetle and the predicted poisoning of the human population did not occur.
Modern pest control was stimulated by the spread across the United States of the Colorado potato beetle. Red weaver ants, here feeding on a snail, have been used to control pests in China, Southeast Asia, and Africa for many centuries.Ĭhemical pesticides were first used around 2500 BC, when the Sumerians used sulphur compounds as insecticides. Alternatively, various methods of biological control can be used including sterilisation programmes. Control of these pests is attempted through exclusion or quarantine, repulsion, physical removal or chemical means. In homes and urban environments, the pests are the rodents, birds, insects and other organisms that share the habitat with humans, and that feed on and/or spoil possessions. Where possible, biological means are used, encouraging the natural enemies of the pests and introducing suitable predators or parasites. This can be achieved by monitoring the crop, only applying pesticides when necessary, and by growing varieties and crops which are resistant to pests. Concern about environment means limiting the use of pesticides in favour of other methods. Ploughing and cultivation of the soil before sowing mitigate the pest burden, and crop rotation helps to reduce the build-up of a certain pest species. In agriculture, pests are kept at bay by mechanical, cultural, chemical and biological means. Pest control measures may be performed as part of an integrated pest management strategy. The human response depends on the importance of the damage done and will range from tolerance, through deterrence and management, to attempts to completely eradicate the pest. Pest control is the regulation or management of a species defined as a pest such as any animal, plant or fungus that impacts adversely on human activities or environment. An agricultural aircraft applies low-insecticide bait against western corn rootworm.
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