PRINCETON COLLEGE

3RD TERM SCHEME OF WORK/ LESSON NOTE

CLASS: JSS2

SUBJECT: AGRICULTURAL SCIENCE

SESSION: 2013/2014

TEACHER: NWEKE EMMANUEL

1 Disease- meaning and definition, types of disease Organism e.g virus, bacteria, fungi, nematode

2 Important diseases of some selected crops e.g Cassava mosaic, yam rot, bacteria wilt of tomatoes

3 General prevention and control of these diseases

4 Pests- meaning of pests- classification of pestsbased on feeding habit, mouth parts and location

5 Important field and storage pests e.g beetle, weevilGrasshopper, caterpillar

6 Economic importance, prevention and control of Insect pests

7 Common disease of farm animals e.g cattle, poultryPigs, sheep, goat, rabbit etc

8 Common animal parasites (endo and ecto parasite)General control measure, economic importance of livestock parasite

9 Prevention of livestock disease and parasite

10 Revision and Examination

3rd TERM 2013/2014 SESSION AGRICULTURE

CLASS: JSS2

WEEK: 1

TOPIC: MEANING AND DEFINITION OF DISEASE

CONTENT

DISEASES OF CROPS

A disease is any alternation or change in the normal physiological function resulting in loss of coordination in the metabolic process of the plant. It can also be defined as the departure from the normal state of health of a plant, recognised by some morphological changes called symptoms.

TYPES OF DISEASE ORGANISMS

Many crop diseases are caused by pathogens (disease-causing micro organisms) and these can be grouped into four namely

a) Parasitic fungib) Virusesc) Bacteriad) Nematode

PARASITIC FUNGI

These are microscopic plants which do not posses chlorophyll, hence cannot manufacture their own food. They are parasitic on crops, though some are saprophytes (living on dead organic matter)

They have no roots, stems and leaves.their body is made up of fine thread like structures called hyphal. Fungi reproduce not by seeds but by spores. These spores can be transmitted by wind, rainstorms, insects, seeds. Examples of disease caused by fungi include black pod disease of cocoa, potato and tomato blight, soft rot of oranges.

VIRUSES

These are very small microscopic organisms smaller than bacteria. They can be seen with the aid of an electron microscope. They cannot live outside the living cell of the host, but multiply rapidly once inside the living cell.they are transmitted by insect vectors such as whiteflies, mealy bugs, aphids etc. Also by gaining entry through wounds , cuttings.

Examples of disease caused by virus are

-Cassava mosaic disease

-Yam mosaic disease

- cocoa swollen shoot

- Groundnut rosette

BACTERIA

These are unicellular and microscopic organisms. Some are parasitic (pathogens) and some are saprophytic. The pathogenic bacteria gain entry into their host plant tissue through stomata wounds, flower or fruits.

Examples of bacteria disease are

-Bacteria wilt of tomato, egg plant etc

- Bacteria blight of cotton

- Wilt of sugarcane

NEMATODE

These are small worm like animals, but they are not true worms. Some are microscopic (cannot be seen with the naked eyes) while some are macroscopic (big enough to be seen with the naked eyes)

Parasitic nematode infest the root system and to some extent the shoot system. Nematodes cause root rot and all sorts of damages to crop plants.

EVALUATION

1 List 4 types of diseases

2 Give 2 examples each of the 4 types of diseases

ASSIGNMENT

Mention 4 method of control of diseases

WEEK: 2

TOPIC: IMPORTANT DISEASES OF SELECTED CROPS

CONTENT

FUNGAL DISEASES

MAIZE SMUT

Causal organism Fungus (Ustilago mayolis)Mode of transmission Through seeds during harvesting, Air borne

spores deposited on leavesSymptoms of disease Grain of affected crop plant turns black mass

of fungal sporesPrevention and control

1, planting healthy seeds 2, treat seeds with fungicides 3, use resistant varieties

BLACKPOD DISEASE OF COCOA

Causal organism Fungus (phytophthora palmivora)Mode of transmission 1, splashing of water from surface of

diseased cocoa to healthy ones2, planting seeds from diseased pods3, injuries on stems or leaves caused by aphids

Symptoms of disease Appearance of brown spots on the podsWhole pod soon rot

Prevention and Control

Remove all infected pods and burnRegular weedingSpray pod with fungicides

VIRAL AND BACTERIAL DISEASES

Groundnut Rosette

Causal organism Virus ( groundnut rosette virus)Mode of transmission Transmitted by a piercing and sucking insect

called aphidsSymptoms Severe reduction in leaf size

Leaf distortion with margin rolling inwardYellow green particles on leaves

Prevention and Control

Early plantingUse resistant varietiesPractice regular weeding

LEAF BLIGHT OF CASSAVA

Causal organism Bacterium (Xanthomas manihotis)Mode of transmission Bacterial cells disposal by wind and rainSymptoms Gum exudation

Vascular necrosisPrevention and control Prune infected parts of plant and burn them

Use clean and healthy cuttingsPlant resistant varieties

EVALUATION

1. Name 2 symptoms of groundnut rosette

2. state the mode of control of cassava leaf blight

ASSIGNMENT

Make a brief note on rice blast and yam mosaic

WEEK: 3

TOPIC: EFFECTS OF CROPS DISEASES

CONTENT

EFFECTS OF CROPS DISEASES

Diseases cause lots of damage to crop and the effects are as follows

1. Diseases generally reduce the yield or productivity of crops

2. They also reduce the quality of crops

3. They cause the malformation of plants or the whole plants

4. They can kill or cause the death of a whole plant

5. They cause reduction in the income of the farmer

6. They increase the cost of production

7. They render vegetables and fruits unattractive and unmarketable

8. Their activities cause retarded growth in crop plants

GENERAL CONTROL OF CROP PLANT DISEASE

Diseases of crop plants can be controlled by the following methods

1. Cultural method

2. Biological method

3. Chemical method

CULTURAL METHOD

This involves the uses of crop rotation, resistant varieties, tillage practices, regular weeding, fallowing, timeliness of planting, pruning , uprooting and burning of infected crops etc to control of infected crops etc to control or prevent diseases

BIOLOGICAL METHOD

This involves the uses of natural enemies of the disease to reduce or totally eliminate the disease.

CHEMICAL METHOD

This involves the use of chemicals such as fungicides, nematicides, insecticides to dust or spray plants and plant materials in order to prevent or control plant diseases.

EVALUATION

1. List 3 methods of controlling crop diseases

2. state 4 effects of diseases

ASSIGNMENT

1. What are pests?

2. Classify crop pests according to their mouth parts

WEEK: 4

TOPIC: MEANING AND CLASSIFICATION OF PESTS

CONTENT

CROP PESTS

A crop pest is any organism whose activities on crop plants hinders the growth of such crops and reduces its yield in the field and destroys food products in the store.

These pests include insects rodents, birds, monkeys etc of all these pests, insect is the most numerous and cause the largest damages to crops. They attack and destroy crops.

CLASSIFICATION OF AGRICULTURAL PESTS

Pests of agricultural crops can be divided into 2 main groups

a) Insect pestsb) Vertebrate pests

INSECT PESTS

Insect pests exceed other pests in number and species. They attack and destroy crop plants at different stages of their growth and development. Insect pests are categorized into the following

i. Biting and chewing insectsii. Piercing and sucking insectsiii. Chewing and boring insects

BITING AND CHEWING INSECTS

These have mandibles (upper jaws) , maxillae (lower jaws) and labrum (upper lip). Their mouth parts are adapted for biting and chewing. They bite and chew the leaves, fruits, young and tender stems of crops. Examples of such insects are grasshoppers, locust, crickets, termites, beetles and larvae of butterflies (known as

caterpillars)

PIERCING AND SUCKING INSECTS

These have stylets and proboscis with which they pierce tissues and suck their sap or juices and in this way cause collapse of cell walls. They are also vectors of viral diseases .e.g. white fly transmit cassava

mosaic virus.

CHEWING AND BORING INSECTS

These have mandibles or a rostrum with which they chew and bore into stored grains and stored products. They reduce these grains to powder. Examples of such insects are rice and maize weevils, beetles etc.

EVALUATION

1. briefly explain biting and chewing insects

2. give 3 examples of chewing and boring insects

ASSIGNMENT

Differentiate between field pests and storage pests

WEEK: 5

TOPIC: CLASSIFICATION BASED ON LOCATION

CONTENT

CLASSIFICATION BASED ON LOCATION

Insect pests are classified into 2 namely:

I field pest

Ii storage pest

FIELD PESTS

These attack crops on the field e.g grasshoppers, caterpillars (stem borer) locust, capsids, aphids, crickets etc

STORAGE PESTS

These are pests that attack crop products in the store. E.g bean bettle, rice and maize.

VERTEBRATE PESTS

Vertebrate pests are non-insect pests. These are bigger pests with backbone. They are few in number when compared with insect pests. They attack crops on the field while some like rats attack stored products.

TYPES OF VERTEBRATES

There are different vertebrate pests that attack crops. The following are the types

a. Birdsb. Rodents

c. Monkeys /cattle

BIRDSBirds attack agricultural crops . These birds have strong beaks used for pecking and cracking seeds of grains. Eg of such birds are pigeons, doves, sparrows. Some birds feed on ripened pawpaw, mango, guava fruits etc. Thereby reducing their yield and market value.

RODENTSThese are rats, grass cutters, giant rats, squirrels etc. their teeth are very sharp, especially the incisors. They attack crops on the fieldand some in the store. They do much damage to cereal especially for example rat attack stored grains in the store.

MONKEYS, GOATS, SHEEPS, LIZARDThese are other vertebrate pests. Monkeys feed on banana and other fruit crops. This also damage branches of tree crops when they jump from one tree to another. Sheep and goats if not well restrained stray into farms and eat leaves and shoots of crops

EVALUATION1. List 3 types of vertebrate pests2. Give 5 examples of vertebrate pests

ASSIGNMENTState 5 economic importance of pests

WEEK: 6

TOPIC: ECONOMIC IMPORTANCE OF PESTS

CONTENT

ECONOMIC IMPORTANCE OF PESTS

The damage caused by pests to agricultural crops either on the field or in storage is enormous. These are listed below

a) Quality of products is reduced: yam beetle feeds on yam tuber creating holes in it thereby reducing its quality

b) Quantity or yield of crops is reduced: yam attacked by rodents, pawpaw fruit eaten by birds, cocoa pods attacked by mirrids cannot be harvested by farmers anymore.

c) Viability of seeds is also reduced: weevils and bettle destroy the embryo of seeds and when such are planted they will not germinate.

d) Pests e.g monkeys and birds cause nuisance to farmers by their noisy habits

e) Farmers profits is also reduced by pests.

METHODS OF PEST CONTROL

There are various methods of controlling pests.the most commonly used methods are discussed below

1. Chemical method2. Physical method3. Biological method4. Cultural method

CHEMICAL METHOD:

This involves the use of chemicals called pesticides are designed to kill pests. Those that kill insects are called insecticides

PHYSICAL METHOD

In this method insect pests can be handpicked and destroyed. Scare crow can be used to scare away birds. Guns can be used to kill monkeys, grass cutters, squirrels and other bigger animals.

BIOLOGICAL METHOD

This method involves the use of natural enemies. Examples include the following

Use of cat to kill rats in the store Encersia Formosa a parasitic wasp can be used to control white

fly Some feed on insects, thereby helping to control their

population.

EVALUATION

1. List 3 method of pest control

2. Explain briefly 3 methods of pest control

ASSIGNMENT

Make a short note on cultural method of control of pests

WEEK: 7

TOPIC: ANIMAL DISEASES

CONTENT

ANIMAL DISEASES

Animal diseases is any abnormality in the functions of the tissue, organs or system of the animal body. This means a disease occurs when the tissue organs or system of the animal body fail to function normally.

GENERAL SIGNS OF ILL HEALTH IN FARM ANIMALS

1. Loss of appetite2. Irregular breathing3. Soft watery and blood stained faeces4. High temperature with much sweating 5. Emaciation6. Rough coat or skin7. Coughing and sneezing 8. Lameness

INFECTIOUS DISEASE: Disease which can affect an animal without the animal having physical contact with an infected animal are called infectious disease.

CONTAGIOUS DISEASE: These are diseases which can only affect an animal if there is physical contact between a healthy animal with an infected animal.

Examples are contagious abortion (brucellosis), foot and mouth disease and inflammation of the udder.

VIRAL DISEASERINDERPEST

Livestock affected Cattle, sheep, goats, pigCausal organism VirusMode of agent Contaminated feed and water

Contact with infected animalSymptoms High temperature

DiarrhoeaLoss of appetite

Control/prevention Vaccination with tissue cultureQuarantineKill all infected animal

BACTERIAL DISEASE

CONTAGIOUS ABORTION

Livestock affected Cattle, sheep goats, pigsCausal organism BacteriaMode of agent Aborted foetusSymptom Abortion

Retained placentaStill birth

Control/prevention Cull all infected Vaccination before breeding

EVALUATION

1. mention 2 symptoms of a viral and bacterial disease

2 List 4 signs of ill health in farm animals.

ASSIGNMENT

Make a short note on anthrax

WEEK: 8

TOPIC: ANIMAL PARASITES

CONTENT

ANIMAL PARASITES

Parasites are living organisms that live inside or outside the body of another organism called the host. They derive their noiurishments directly from the host. They are usually dangerous and of no benefit to the host.

Animal parasites can be divided into 2 namely

a. External parasites (Ectoparasites)b. Internal parasites (Endoparasites)

ECTOPARASITEThese are parasites that live on the surface of the animal body and feed on its blood or skin. Examples are ticks, lice, mites etc.

ENDOPARASITE

These are parasites that live in the internal organs of their host e.g muscle tissue or blood cells examples are roundworm, liverfluke and tapeworm.

EFFECTS OF TICKS

I. Loss of blood (anaemia). They suck blood from their hosts by embedding a special piercing organ deep into the skin of the host animal.

II. Severe irritation to the hostIII. Sores are produced on the skin of affected animal

CONTROL MEASURESI. Dip dust or spray affected animals with chemical compounds

such as lindane, benzeII. Rotational grazing will prevent the survival of ticks by depriving

them of their only source of supply.

EFFECTS OF TAPEWORM

1. The adult tapeworm takes a lot of food and nutrients from the host leading to emaciation

2. Abdominal irritation and pain3. General weakness4. Production and growth rate of host animals is greatly reduced.

CONTROL OF TAPEWORM1. Do not allow pigs come in contact human excretion2. Pig meat must be cooked very well to kill any ripe bladder

worms on it.3. Meat of pigs should be properly inspected4. Pasture should be burnt.

EVALUATION

1. what are parasites?

2. mention 2 control measures of ticks and tapeworm

ASSIGNMENT

Write the effects and control of roundworm.

WEEK: 9

TOPIC: ANIMAL PARASITES

CONTENT

PREVENTION OF LIVESTOCK DISEASE AND PARASITE

Prevention measures are all the practices put in place to hinder the occurrence of the diseases and attacks by the parasite.

These measures include quarantine, vaccination and farm hygiene

QUARRANTINE

Under this measure, all animals imported from another country are isolated and kept under close observation with the main aim of preventing the introduction of foreign diseases. If the animals are found to be free from any disease symptom, they are then allowed entry into the country, if otherwise; they are destroyed or not permitted into the country.

VACCINATION

This involves the administration of substances called vaccine to the animal’s body at different stages of their growth.

Vaccine is a fluid which contain the weak strains of the disease pathogen which is introduced into the body of the healthy animal orally or by injection so that the healthy animal can stage immunity in case of eventual attack by the disease organism.

EVALUATION

1. mention 2 prevention of animal disease

2. Explain 2 preventive measures taken in livestock

ASSIGNMENT

Make a brief note on farm hygiene as a way of preventing parasites.