关键词: 季节性干旱, 作物水分亏缺指数, 越冬作物, 干旱频率, 干旱站次比

Abstract: Honeybee disease is caused by pathogens,and also brought about by many ecological factors. The main infecting factors are:1.climate (including temperature, humidity and wind);2.biological circumstance in agriculture and nectar sorce pollution;3.degeneration of honeybee and forest re-duction;4.pesticides and chemicals;5.pathogene's coordinated action.It's suggested that hon-eybee diseases are caused by ecological factors comprehensively,and,in some cases,an ecological factor may play a leading and guiding role.

Key words: seasonal drought, crop water deficit index, wintering crop, drought frequency, station proportion of drought frequency.