CONTENT
- Meaning of crop pest
- Types of crop pest
- Classification of insect pest
MEANING OF CROP PEST
A crop pest can be defined as any organism capable of causing damage to the crop.
TYPES OF CROP PEST
Important crop pest are grouped in to the following classes;
- Insects
- Birds
- Rodents
- Monkeys
- Man
- Nematodes
CLASSIFICATION OF INSECT PEST
- Biting and chewing insects: they possess strong mandible and maxillae (mouth parts) which enable them to bite and chew plant parts e.g termites, grasshoppers, leafworm, mantids, locusts and beetles.
- Piercing and sucking insects: they possess stong mouthparts called proboscis which enable them to pierce through plants and suck liquid materials from them. Examples are aphids, cotton strainers, mealy bugs, scale insects, capsids, mirids and white flies.
- Burrowing insects: they and their larva stage are capable of burrowing the tissue of the plant parts or fruits or seeds. Examples are bean beetles, stem borers, maize weevils and rice weevils.
EVALUATION
- What are crop pests?
- List the three classes of insect pests.
IMPORTANT PESTS OF MAJOR CROPS
| Pest | Crops Attacked | Natures of Damages and Economic Importance | Prevention and Control Measures |
| Stem burrower | Cereals e.g. rice, maize, guinea corn. | Larvae bore holes into stemsThey eat up the tissuesThey weaken the plant | Uproot and burn infected plantSpray with insecticides e.g. Gammalin 20 Reduced growth and yieldEarly planting Crop rotation |
| Army Worm | Cereals e.g. maize | Larvae invade and eat up leaves and stemReduce photosynthesisRetarded growthReduced yield | Hand pickingSpray with insecticides. E.g. DDT |
| Pod burrower | Legumes e.g. cowpea, soyabeans | Larvae bore into the podThey eat up the seedsReduced yield | Crop rotationEarly harvesting Spray with insecticidesIntroduce diseases. |
| Aphids | Legumes e.g. cowpea, soyabeans | Stunted growthGalls on leavesVectors of disease e.g. rosette, mosaic disease of cowpea | Spray with insecticides to kill vectorUproot and burn infected plant |
| Leaf beetle | Legumes e.g. cowpea, soyabeans | They eat up the leavesReduce photosynthesisReduced yield | Spray with insecticidesUse pest-resistant varieties. |
| Cocoa mirids (capsids) | Beverages e.g. Cocoa | They inject toxic saliva into plantTransmits fungal diseasesReduced yieldStunted growth | Spray with insecticides e.g. Gammalin 20Regular Weeding |
| Yam beetles | Tubers e.g yam | Boreholes into yam tubersReduced yieldReduction in quality and market value | Dust yam setts with Adrin dust before plantingCrop rotation |
| Cassava Mealybugs | Tubers e.g cassava | Twisting of stem and reduced internodesSwelling of shootsReduced yield | Early planting Use pest-resistant varieties.Cutting treatmentSpray with insecticides |
| Green Spidermite | Tubers e.g cassava | They feed on the leavesReduce rate of photosynthesisReduced yield | Use biological controlSpray with insecticides |
| Variegated Grasshopper | Tubers e.g Cassava, yam | Adults and larvae eat up the leaves and stemReduce the rate of photosynthesisReduced growthReduced yield | Hand pickingSpray with insecticides e.g. Adrex 40 |
| Cotton Stainer | Cotton | They pierce and suck sap from plantsProduce toxic salivaTransmit diseasesReduce quality of boll Leaf distortion | Hand pickingSpray with insecticides |
| Cotton bollworm | Cotton | Larvae feeds on the seeds of cottonCrop rotationDestroy the lint and reduce its qualityPremature fall of cotton boll | Spray with insecticides to kill insectsBurn cotton plant debris after harvesting. |
| Thrips | Vegetables e.g. Onion, tomato | Browning of leavesWilting of plantReduced yield | Spray with insecticides |
| Leaf rollers | Vegetable | Rolling and twisting of leaves Reduction in rate of photosynthesisReduced yield | Spray with insecticides e.g. Vetox 85 |
| Leaf beetle | Vegetables e.g. pepper, okra and tomato | They eat up leaves and stemsReduced photosynthesis Reduction in yield and quality | Spray with appropriate insecticides e.g. Vetox 85 |
| Bean beetle, grain weevils | Stored produce e.g. rice, cowpea and maize. | Boreholes into grains and eat them upReduce the quality of stored produceReduced farmer’s incomeReduce the market value of grainsReduce viability of insfested grains | Early harvestingProper storage of produceProper cleaning and fumigation of store with phostoxin tablets or with lindane dust.Store grains over fire placesProper drying of seeds to reduce moisture content and kill the eggs and larva of pests. |
| Birds | Rice, maize, millets and sorghum | Feed on grains in the fieldReduction in quality and yieldReduction in income of farmers | Use of bird scarer or scare crowUse of cage traps with baitsShooting with catapultDrumming or noise making on the farmUse of explosive mechanism at regular intervalsUse of avicidesFencing /Screening farms in greenhouse |
| Rodents e.g. bush rabbit, rats and squirrel | Rice, yam, cassava and fruits | They feed on cropsDestroy whole plantReduction in yieldIncrease in cost of production | Trapping with braits.Use of rodenticidesUse of string/wire trapsUse of predators e.g. dogs and catsClean weeding of farmsShooting and fencing Use of pit traps |
| Monkeys | Cocoa mango, banana, and orange | They eat up the fruits Reduce the quality of fruitsLosses to the farmer | Use trapsShooting with gun where possible. |
EVALUATION
- List two ways of controlling cocoa mirids
- List two ways of controlling monkeys
ECONOMIC IMPORTANCE OF INSECT PESTS IN CROP PRODUCTION
- They destroy crops in the fields through their biting, chewing, boring, sucking and defoliation activities.
- They cause reduction in viability of stored produce
- Spot of injuries by insect pests predispose crops to pathogen attack
- They increase the cost of production as they are being controlled
- They render vegetables and fruits unattractive and unmarketable
- Some are of vectors of disease
- The profits of farmers are reduced
- They reduce the quality of produce either in the store or in the field
- They generally reduce the yield of crops
- They can also cause total death of crop plants.
GENERAL EVALUATION
- What are pathogens?
- List five pathogens you know
- List four economic importance of insect pest
READING ASSIGNMENT
Revision questions 3 and 8 Essential Agricultural Science for Senior Secondary Schools Chapter 26, page 247
WEEKEND ASSIGNMENT
SECTION A
- _____ is responsible for damages in crops. A. weeds B. water C. air D. pests
- The following are rodents except _____. ?A. rat B. grasscutter C.squirrel D.monkey
- The following are bitting and chewing insect except ____. A. termites B. capsids C.locust D. beetles
- Stem burrowers will attack A. cereals B. legumes C. tubers D. spices
- Cotton strainers and meleabugs are examples of _____ insects. A. biting B. chewing C. piercing D. burrowing
SECTION B
- A. What are pests
B. List the five types of pests
2. A. List five effects of pests in crop production
B. List three control measures of plant disease
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