Pesticides should not be used indiscriminately. Only very accurate dose
should be applied at appropriate time, slight excess of the pesticide is
extremely harmful.
(i) Pesticides are harmful to soil biota. Therefore, they reduce soil fertility.
(ii)They pass into ground water and make it toxic.
(iii) They enter the crop plants and make them toxic.
(iv) Pesticides pass into surface water through run off from sprayed fields and harm the aquatic biota.