Maharashtra Board Class 11 Agriculture Science and Technology Chapter 11 Pest and Disease Control PDF Download

Pest And Disease Control

Meaning And Types Of Pest And Diseases

Meaning Of Pest

Pest means any living organism that multiplies in large number and cause damage or disease to human, animals, plants or property. Pest indicates the harmful insect or this includes insects, mites, fungi, bacteria, viruses, rats, birds, animals nematodes, weeds, etc. The terms pest is derived from Latin word pestis which means damage.

The insects are dominant in ecosystem as insects have external skeleton, small size, prolific reproduction, efficient body system, adoptability to new environment, remain dormant in adverse condition.

Can you recall?

Names of human diseases

Name the organisms responsible for diseases.

Do you know?

When plant is said healthy?

Plant growth and development is good and it is capable of reproduction.

When plant physiological processes [Cell division and growth, absorption of water and minerals from soil, photosynthesis, respiration, food storage, etc.] are performing smoothly.

Can you tell?

Names of the some insects familiar to you.

The body parts of insects.

The examples of harmful and useful insects.

Teacher's Note

A pest is any living thing that damages our crops. In India, farmers lose crores of rupees every year because of pests eating their crops. We must learn to control them.

Exam Trick

Remember: Pest = harmful insect. Just like a thief in your house, pests steal your crops. The word "pest" comes from Latin "pestis" meaning damage or harm.

Points To Remember

A pest is any organism that harms plants, animals, or humans.
Pests include insects, rats, birds, fungi, bacteria, and viruses.
Insects are the most common pests in farms.
Pests multiply very fast and cause big losses.
We must control pests to save our crops and money.

Meaning Of Diseases

Disease is defined as physiological or structural deformity that is harmful to plant or any of its parts or produces that reduces their economic value. Diseases of plant are responsible for plant damage and their produce. Damage due to diseases in India is estimated approximately 500 crores per year. Disease may be caused by living organism which are affected by factors as temperature, moisture, aeration, deficiency or excess of plant nutrients, soil pH (acidity or alkalinity), etc.

Try this

Take some disease affected seed and observe.

Always remember

The economic threshold level is the pest density at which control measures should be determined to prevent an increasing pest population from reaching economic damage level.

Teacher's Note

Plant disease is like human sickness. Just as we get fever from bacteria, plants get sick from fungi and viruses. In India, plant diseases cost farmers about 500 crores rupees every year.

Exam Trick

Remember: Disease = sick plant. Diseases come from fungus, bacteria, or viruses. It is like the flu in humans but happens to plants.

Points To Remember

Disease makes plants sick and weak.
Diseases are caused by fungi, bacteria, viruses, and nematodes.
Temperature and moisture help diseases spread fast.
Plant diseases cost India 500 crores rupees every year.
We must control diseases to get good crops.

Types Of Pest And Disease

[A] Types Of Pest On Basis Of Incidence

1. Regular pest: The regular pest occur most frequently on the crop and such pest have close association with a particular crop. These pest are expected to occur on the crop sometime before harvest e.g. Thrips on chilli, Jassids on paddy, Aphids on mustard, Fruit borers on brinjal.

2. Sporadic pest: The sporadic pest occur in a few isolated localities occasionally in certain years e.g. rice stink bug on rice, slug caterpillar on castor.

3. Occasional pest: Many pest occur rather infrequently and close association with particular crop is absent e.g. case warm of rice, the mango stem borer.

4. Seasonal pest: Those pest which occur mostly during a particular part of the year. The incidence of these pests are governed by environmental factors in a locality. e.g. red hairy caterpillar on groundnut during April-May in certain localities of the south India, rice grass hopper during August – September in U.P.

5. Persistent pest: Pest that occur on a crop throughout the year are known as persistent pest e.g. mealy bugs on sugarcane.

6. Potential pest: These pest normally cause little loss but may become highly destructive resulting from some disturbance in the environment and the consequent increase in their number e.g. brown plant hopper on paddy.

Teacher's Note

Different pests attack crops at different times. Some pests come every year, while others come only sometimes. A farmer must know when each pest comes to his fields so he can stop it in time.

Exam Trick

Remember: Regular pest = comes every year. Seasonal pest = comes only in one season. Occasional pest = comes sometimes and rarely.

Points To Remember

Regular pests come to the same crop every year.
Seasonal pests come only in one season like April-May.
Occasional pests come rarely and not every year.
Persistent pests stay on the crop all year long.
Potential pests become harmful when conditions change.

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