1930-31 - Deadly famine, exacerbated by destruction of prickly pear cactus Opuntia dillenii by cochineal beetle. This cactus, previously introduced in Fort Dauphin, spread over Anosy and Androy regions:it had provided protection to herders and their cattle as well as both fruit and water to people and cattle. Eminent damages on local species of Castor oil plant are also observed . This resulted in half the population of in the Tsihombe district decreasing by half, though the number of dead versus those who emigrated out of the area is unclear.