Describe briefly the side effects of preventive and control measures of method diseases and pests of crops under the following headings: (a) chemical control (b) biological control (c) cultural of control .
Explanation
The side effects of various preventive and control measures of diseases and pests of crops are:
(a) Chemical method of control:
(i) Almost all the chemicals used are toxic to man and domestic animals.
(ii) Some beneficial insects of soil organisms may be destroyed.
(iii) Pests and diseases may develop resistance to chemical. (iv) Some chemicals may cause water pollution.
(v) Empty containers could be a source of poison when used as containers for consumables.
(b) Biological method of control:
(i) The new organisms introduced may start attacking crops which were formerly free from attack.
(ii) The predators introduced may feed on other beneficial insects causing imbalance in the ecosystem.
(c) Cultural method of control:
(i) The use of fire may spread to other farms
(ii) The use of fire may kill some beneficial organisms.
(iii) It can lead to destruction and losses of organic matter in the soil.
(iv) It can also destroy the soil structure