Cover Image
close this bookPrimary School Agriculture Volume II: Background Information (GTZ, 1985, 190 p.)
View the document(introduction...)
View the documentPreface
close this folderPart I: Farming methods
View the document1. Objectives
close this folder2. Traditional agriculture
View the document2.1 Traditional land use systems from shifting cultivation to degraded bush fallow
View the document2.2 Traditional Farming Methods
View the document2.3 Instruments for School Surveys of Traditional Agriculture
close this folder3. Scientific agriculture
View the document3.1 The meanings of scientific agriculture
View the document3.2 Scientific agriculture in Cameroon
View the document3.3 Conclusion
close this folder4. New approaches to farming in the tropics
View the document4.1 The need for a new approach
View the document4.2 The Main Approaches
View the document4.3 Backing for the New Approaches
View the document4.4 Suggestions for school activities
View the document4.5 Some Terms Used in Connection with Farming Methods
close this folderPart II: Crops
close this folder1. Leguminous crops
View the document(introduction...)
View the document1.1 The Bean
View the document1.2 The Cowpea
View the document1.3 The Groundnut
close this folder2. Starch-producing crops
View the document(introduction...)
View the document2.1 Cereals
View the document2.2 Root and Tuber Crops
close this folder3. Tree crops
View the document(introduction...)
View the document3.1 Coffee
View the document3.2 Cocoa
close this folder4. Tables of yields and farm activities
View the document4.1 Tables of yields
View the document4.2 Farm activities associated with different crops
close this folderPart III: Crop storage
close this folder1. The Grain storage problem
View the document1.1 Extent of the problem
View the document1.2 Types of grain storage losses
View the document1.3 Costs and benefits of grain storage
close this folder2. Properties of grain in storage
View the document(introduction...)
View the document2.1 Grain kernel structure
View the document2.2 Biology of grain in storage
View the document2.3 Moisture, temperature, and respiration
View the document2.4 Conclusions
close this folder3. How to prepare your grain for storage
View the document3.1 Harvesting: when is grain ready
View the document3.2 Grain cleaning
View the document3.3 Selection of grain for storage
View the document3.4 Preparing and cleaning your grain store
close this folder4. Drying grain
View the document4.1 Why grains must be dried
View the document4.2 What Makes grain dry
View the document4.3 How much drying is enough: Safe drying limits
View the document4.4 How to test the grain for dryness
View the document4.5 Drying methods
close this folder5. Storing grain
View the document5.1 Difference between grain storage and grain drying
View the document5.2 Grain storage principles
View the document5.3 Storage methods
close this folder6. Pests of stored grain
View the document6.1 Mould and fungus
View the document6.2 Insects
close this folder7. Insect control
View the document(introduction...)
View the document7.1 Traditional methods
View the document7.2 Chemical methods
close this folder8. Rats
View the document(introduction...)
View the document8.1 Some facts about rats
View the document8.2 Environment and habits of rats
View the document8.3 How to find rats
View the document8.4 Non-chemical rat control methods
View the document8.5 Chemical rat control methods
View the document9. Costs and benefits of improved grain storage: an example
close this folder10. Tuber preservation
View the document10.1 Present state of tuber storage
View the document10.2 What happens to tubers in storage
View the document10.3 Preparing Tubers for Storage
View the document10.4 General storage principles
View the document10.5 Tuber stores
View the document10.6 Storage pests of tubers
View the documentReferences

10.6 Storage pests of tubers

We have already discussed the rotting and spoilage problems caused by fungi and moulds. Now the insect and animal pests will be discussed.

The major insect pest of the potato tuber is the Sweet Potato Weevil. It looks like the Rice Weevil shown on p. 170. The weevil often begins to attack the tuber in the ground before it is harvested. Then, when the tuber is carried to the store, the larvae, eggs, and adults are all carried to the store. Once in the store, they move into other tubers and spoil them. This weevil makes tiny, hard-to-see holes in the skin of the potato. However, fungus and other diseases can enter easily through this holes.

The best control method is to rotate the crop every two years so that the eggs which are laid in the soil will not find food when they hatch into larvae. They will die and soon the field will be free of the pest. Harvesting earlier than normal is helpful. The weevil likes mature, ripe sweet potatoes. Leaving the potatoes in the ground can be dangerous - the weevils can fly to fields where they know the potatoes are growing.

Insecticide - Malathion or Actellic - can be used if it is necessary. Check up in section 7.2, for information about chemical control of the Sweet Potato Weevil. The same rate of application should be followed with sweet potatoes as with grains.

Yams sometimes have a problem with termites in the field. Harvesting earlier is helpful. In storage yams sometimes are bothered by a weevil entering the tuber through the cut crown (where the sett was taken from). Rub wood ash on the cut before you store it. This helps to keep the cut free of fungi and insects.
If rats and other animals bother the tubers, trapping or harvesting early is the only control method.