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Q. No. 1: Why should preventive measures and biological control methods be preferred for protecting crops?

Ans: Sometimes crops are very much affected or destroyed by the weeds, insects pests and diseases. For example
(i) Weeds compete for food, space and light. They use the nutrients from the soil and reduce the growth of the crop.
(ii) Insect pests affect the health of the crop and reduce its yield.
(iii) The pathogens like bacteria, viruses and fungi cause the disease in the plants. Therefore they must be controlled by using suitable preventive masures.

 

Q. No. 2: What factors may be responsible for losses of grains during storage?
Ans:
During the storage of grains both biotic and abiotic factors cause losses to the grain. Biotic factors such as insects, rodents, mites, fungi, bacteria, etc. and various abiotic factors such as moisture, temperature, lack of sunlight, etc. are responsible for losses of grains.



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Why should preventive measures and biological control methods be preferred for protecting crops

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