DESCRIPTION OF THE DAMAGE DONE BY PESTS
Subject :Agricultural science
Topic :
DESCRIPTION OF THE DAMAGE DONE BY PESTS
Class :
Basic 7 / JSS 1
Term :
Third Term
Week :
Week 7
Instructional Materials :
- pictures of weeds
- samples of weeds
Reference Materials
- Scheme of Work
- Online Information
- Textbooks
- Workbooks
- 9 Year Basic Education Curriculum
Previous Knowledge :
The pupils have previous knowledge of
MEANING, TYPES AND CLASSIFICATION OF PESTS
Behavioural Objectives : At the end of the lesson, the pupils should be able to
- say the meaning of dissemination
- list methods of weed dissemination
- write out the advantages of weed dissemination
- say the disadvantages of weed dissemination
CONTENT
- Description of the Damage Done by Pests
- Table Showing the Description of Damage Done by Crop Pests
Description of the Damage Done by Pests
Crop pests do a lot of damage to crops either on the farm or in the store. The damages done by pests include:
(i) Some insect pests are carriers of diseases which they transmit to healthy plants.
Examples of diseases transmitted by insect are: ground nut rosette, cassava mosaic, swollen shoot of cocoa, etc.
(ii) Mammals (rodents) e.g. rats, grass-cutter eat up the tubers of yam, cassava and potato.
(iii) The birds destroy rice, sorghum, beans, maize and fruits at various stages of their growth on the farm.
Table Showing the Description of Damage Done by Crop Pests
| S/n | Crop Pest | Crop(s) Damaged | Nature of Damage Caused/Effects on Crops | |
| 1 | Grasshoppers/locust | Cassava, yam, cowpea | (i) They eat vegetative parts of plants such as leaves, stems, fruits and flowers (ii) They reduce the rate of photosynthesis (iii) They reduce growth and yield. | |
| 2. | Aphids | Cowpea, soya beans, cocoa, kola, rubber, groundnut, lettuce, etc. | (i) They pierce plant parts and suck sap and juice. (ii) They transmit virus diseases. (iii) They produce honey dew which spreads on the leaf and as such disturbs photosynthetic ability. | |
| 3. | Weevils | Maize, rice, cowpea, kola, potato, etc. | (i) They bore holes into seeds or fruits causing physical damage. (ii) They eat up the seeds content and as such reduce its market value. (iii) They reduce the viability of planting materials. | |
| 4. | Stem borer | Maize, sorghum, rice, sugar cane | (i) They destroy stems of young crop plant by boring holes into them. (ii) They cause wilting and tillering. (iii) They cause stunted growth. | |
| 5. | Mealy bugs | Cassava, cocoa, kola, rubber, pawpaw, pineapple. | (i) They cause swelling and shortening of the internodes (ii) They suck sap and transmit viral diseases e.g. swollen shoot of cocoa. | |
Description of the Damage Done by Pests
Crop pests do a lot of damage to crops either on the farm or in the store. The damages done by pests include:
(i) Some insect pests are carriers of diseases which they transmit to healthy plants.
Examples of diseases transmitted by insect are: ground nut rosette, cassava mosaic, swollen shoot of cocoa, etc.
(ii) Mammals (rodents) e.g. rats, grass-cutter eat up the tubers of yam, cassava and potato.
(iii) The birds destroy rice, sorghum, beans, maize and fruits at various stages of their growth on the farm.
Table Showing the Description of Damage Done by Crop Pests
EVALUATION
- State two effects of the following pests of crops: (i) Mealy bugs (ii) Grasshoppers (iii) Weevils
- Name three crops that can be attacked by grasshoppers.
EFFECTS OF CROP PESTS ON YIELD
CONTENT
- Effects of Crop Pests on Yield
- Economic Importance of Pests
Effects of Crop Pests on Yield
Crop pests have the following effects on crop yield:
- Heavy attack by pests may result in total crop failure.
- Infected seeds, crops, and vegetables have low market value.
- Pests reduce the quality of crops.
- Pests eat up leaves of crops, thereby reducing the photosynthetic activity of the plant.
- They cause injury which may predisposes crop to diseases attack.
- Infected seeds usually have low viability (germination) capacity.
- Some insects like aphids transmit diseases to crops.
- Pests reduce the quantity of crops.
Economic Importance of Pests
The following are the economic importance of pests:
- Reduction of quality of products
- Control of pests leads to increase of production.
- Reduction in the profit of farmers.
- Pests e.g monkeys and birds cause nuisance to farmers by their noisy habits.
- Pests can also cause diseases to crop farmers.
- All the points under effects of crop pests on yield above.
Presentation
The topic is presented step by step
Step 1:
The class teacher revises the previous topics
Step 2.
He introduces the new topic
Step 3:
The class teacher allows the pupils to give their own examples and he corrects them when the needs arise
:
EVALUATION
- State five effects of pests on crop yield.
Conclusion :
The class teacher wraps up or conclude the lesson by giving out short note to summarize the topic that he or she has just taught.
The class teacher also goes round to make sure that the notes are well copied or well written by the pupils.
He or she does the necessary corrections when and where the needs arise.
Assignment :
Prepare for the next lesson by reading about