Sentences of a paragraph are given below in jumbled order. Arrange the sentences in the correct order to form a meaningful and coherent paragraph.
A. Swarms have wreaked havoc on crops and caused famines and mass migrations.
B. Since prehistoric times, locusts have caused plagues.
C. Traditional methods of control rely on the use of pesticides from the ground or the air, although biological control approaches are also making great strides.
D. Changes in agricultural practices and improved observation of areas where swarms tend to form have lately allowed control measures to be implemented at an earlier stage.