In Japan, farmers used to walk around the rice paddies in procession yelling, with drums, alarm bells, torches to drive away rice bugs. This is called "mushi-oi" or "mushi-okuri" (meaning driving away noxious insects). In the Edo Era, a new method was invented, in which whale oil was sprayed on rice paddies to destroy harmful insect pests on rice, which was used until the early Showa Era. In the days before World War II, naturally-derived pesticides such as pyrethrums (the same ingredient as that in mosquito coils) and nicotine sulfate (from tobacco), or naturally derived fungicides such as copper and lime sulphur were used. However, weed control depended solely on hand weeding, and this continued until herbicides were developed after the war. Hand weeding under the scorching sun is very hard labor.