Stored-grain Insect Areawide Pest Management

摘要

Wheat is harvested in the USA from June in the southern part of the wheat-growing region until August in the northern part (Ragstrum and Reid, 1988). Grain temperature, grain moisture and storage time are the main factors determining the risk of economic losses from insect infestation. Wheat harvested in June in southern regions is generally at higher risk because grain temperature is suitable for insect movement and reproduction for a longer time than is wheat harvested in August in northern regions. Currently, management of insect pests in the wheat marketing system is usually sufficiently effective to slow insect population growth and prevent insect populations from increasing exponentially. During the 1977 and 1978 storage seasons in the USA, the average insect pest population in the wheat marketing system increased from 0.15 insects/kg (four insects per bushel) in June to 0.44 insects/kg (12 insects per bushel) in October, and then decreased as grain cooled in autumn and winter (Hagstrum and Heid, 1988).The profits and losses from merchandizing grain are greater and more apparent to managers of grain businesses than the costs and losses from insect pests in the elevator. Perhaps, for the same reason, grain merchandizing is generally given the highest priority and the greatest attention, and pest management and other aspects of grain management receive less attention. Any advanced insect pest management programme that is introduced into this corporate culture must be cost-effective, minimize the risk of insect problems and require minimal attention.