Methods Of Weed And Pest Control III JSS1 Agricultural Science Lesson Note

ECONOMIC IMPORTANCE, PREVENTION AND CONTROL OF INSECT PESTS

Pest may cause damage to crops in the following ways:

1.                       Insect pests destroy field crops through their activities such as biting, chewing, boring, and sucking
2.                       They cause reduce in the viability (germinating capacity) of stored produce
3.                         Heavy attack by insect pests may lead to total failure
4.                       They reduce the market of crops, especially fruits and vegetables
5.                       Control of insect pests increases the cost of production
6.                       Some insect pests act as vectors of plant diseases.
7.                      Insect pests reduce the yield (quantity) and quality of crops either in the field store.

PREVENTION AND CONTROL OF INSECT PESTS

Generally, insect pests can be effectively controlled through the following measures.

a)               Cultural control

b)               Physical control

c)               Chemical control

d)               Prohibition

e)               Quarantine

f)               Biological control

 CULTURAL CONTROL

This involves the use of good cultural practices to reduce or destroy insect populations and to help crops escape insect attacks.  These cultural practices include: 

1.           Crop rotation
2.           Tillage
3.           Early planting
4.           Adequate and regular
5.           Planting resistant
6.           Timely harvesting
7.           Burning

 PHYSICAL CONTROL

This involves the physical removal of insect pests from the farm.  The following insect pests on the farm though:  (i)   Hand Picking  (ii)  Airtight storage

BIOLOGICAL CONTROL

This involves the introduction of the natural enemies of the insect pest.  The pest enemies are introduced to feed on the insect pest thereby reducing the population of the pest.  For instance, ladybirds are introduced in an aphid-infested farm to eat up the aphid.

CHEMICAL CONTROL

This is the use of chemicals to protect crops from insect attack and if the attack is established they are used to kill the insect pests at various stages of their life cycles.  Chemical control is the most effective method of controlling insect pests and chemicals used for insect control include:

1. Insecticides:  These are chemicals specifically used for controlling insect pests.  They may be applied in the form of solids such as dust or the form of emulsions or sprays.  Examples include Gammalin 20, Vector, Aldrin dust, and so on.
2.           Fumigants:  These are insecticides that are in the form of vapor.  They are usually enclosed in air-tight containers.  Examples include hydrogen cyanide, methyl bromide, and ethylene.

QUARANTINE

Quarantine is a period of isolation and observation imposed by law on imported materials including seeds, plants, and animals.  The materials are kept long enough to observe them for any disease symptoms.  If symptoms are detected, the materials are either destroyed or exported to the country where it was purchased at the expense of the importer.