It also involved input from horticulturalists and botanists. Pastoralists have trade relations with agriculturalists, horticulturalists, and other groups. What horticulturalists and gardeners often refer to as mildew is more precisely powdery mildew. The Korowai are hunter-gatherers and horticulturalists who practice shifting cultivation. Madagascar was colonized by Iron-age pastoralists, horticulturalists, and fishermen, not big-game hunters. Gardening enthusiasts and professional horticulturalists have long bred daylily species for their attractive flowers. As horticulturalists, they farmed maize and indigenous crops from the Eastern Agricultural Complex. It is used by farmers and horticulturalists to produce better crops with desirable qualities. The inhabitants of D'Entrecasteaux Islands are indigenous subsistence horticulturalists living in small, traditional settlements. They are also often persecuted by horticulturalists because they frequently raid fruit and vegetable crops. The garden contains and preserves the botanical collection of horticulturalists James and Janice Gerdemann. The people of the Trobriand Islands are mostly subsistence horticulturalists who live in traditional settlements. Its crop centre provides advisory services to horticulturalists on commercially viable new crops. They were skilled horticulturalists, raising numerous, distinct varieties of corn, beans and squash. The Semai are semi-sedentary horticulturalists who practice "slash and burn" agriculture.