Possible Clues:

• Subject for Ms. Carson
• Spray banned in '72
• Ms. Carson's target
• Banned pesticide, for short
• Pesticide banned in '72
• Noted organochloride, in brief
• Rachel Carson subject
• Subj. of Rachel Carson's "Silent Spring"
• Insecticide banned in the U.S
• Pesticide banned in some countries since 1972