Answer:
One reason that DDT has stopped being used to combat the boll weevil was increased resistance of the boll weevil.
Step-by-step explanation:
Boll weevil can be described as a kind of a beetle which feeds on the buds and flowers of the cotton crop plant. Pesticides such as DDT were initially used to kill these pests. But with the passage of time, we observe that the Boll weevil develop resistance for the pesticide. As the organisms carrying the resistant genes are better able to survive and reproduce, the DDT starts to become ineffective as more and more resistant beetles are produced.