It was the most used insecticide that had arsenic in it. It was used against the potato beetle and the gypsy moth. It replaced the even more toxic Paris Green. It was later used to kill certain moths, mosquitoes, and pests of cranberries. It was found that it stayed inside fruits even after washing off, so it was replaced with DDT. It was completely banned in 1988.
Lead arsenate Facts for Kids. Kiddle Encyclopedia.