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Lecture 1- The Concept and Evolution of Pests
Definition of pests
An early definition of a pest was an organism that interferes with man
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A more acceptable
definition of a pest is any organism that injures, spreads disease, feeds on ornamental plants of
aesthetic or economic value, or competes for food and water with humans, domestic animals or crops
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The organism only
attains pest status when its population increases to a level where it inflicts economic or aesthetic loss to
human beings
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They have three pairs of jointed legs
attached to thorax
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Nematodes
Plant-parasitic nematodes are microscopic organisms usually found in soil or other media in which
plants are grown
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Both have smooth elongated soft bodies and contain a pair
of antennae and a pair of stalked eyes
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Damage is caused by the radula as they feed on plant tissue
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They are usually minute organisms
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In agriculture, weeds are defined as plants
that compete for water, nutrient, light and space with cultivated plants
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Vertebrates
Several vertebrates can and have attained pest status in Jamaica
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Insects
Insects are the major organisms that have attained pest status
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They are the most successful animals
on earth
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From this early form evolved
variations in the wings and the ability to fold the wings
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Complete metamorphosis also evolved
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To manage a pest, there must be
knowledge and understanding of the factors contributing to the imbalance
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Pest Outbreaks – Human Response
Post World War II attempts by humans to deal with pest outbreaks focused on eradication
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Both these approaches employed the use of
pesticides and more pesticides
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As a result, Jamaica imports approximately 700,000 kg of pesticides/year
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Evolution of pests
Man’s early interaction with arthropods as pests involved parasitic arthropods
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The
development of agricultural systems (cultivation of plants and domestication of animals) encouraged
some organism while displacing others
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Factors contributing to the attainment of pest status
Recent pest problems are associated with action taken to improve crop production
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History of pest Management
2500 BC ancient Sumerians used sulfur as an insecticide
Egyptians and Chinese used insecticides formulated from herbs and soils
300 BC Chinese used crop phenology and timed planting of crop to avoid pests
300 BC Chinese discovered the use of natural enemies
1101 soap was used to control pests
1600s tobacco, insecticides from other herbs and arsenic
1700 the use of resistant varieties
Mid 1800s legislative control introduced
1800s – development of special application equipment
1920s – 1930s emphasis placed on sanitation, timing, environmental manipulation and low use
of insecticide
1939 saw the introduction of synthetic organic insecticides (DDT)
Use of insecticide was based only on efficacy against the pest
Backlashes of pesticide control in the 1950s led to the advent of the concept of pest management
in the 1960s



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