DDT is great for killing skeeters, but in Africa apparently it killed tiny wasps that ate catepillars. So the catepillars ate thatched roofs and caused them to collapse.
Then DDT collected in the rats and killed the cats that ate the rats. So the British had to bring in about 13,000 new cats to kill the rats. Some say they were parachuted. Maybe not. But apparently it's a true story.
Posted by Bob Wallace, who prefers pugs to cats, because cats are EVIL!!!