苹果全爪螨在苹果园中种群密度消长规律的研究

STUDY OF THE RULE OF POPULATIONS DENSITY RISE AND FALL OF THE EUROPEAN RED MITE IN APPLE ORCHARDS

苹果全爪螨在苹果园中的年中种群消长曲线,为一两端平缓,中部陡然升高的单峰曲线,其前期密度和开始迅速增长的时期直接关系到年中猖獗发生阶段所持续的时间、高峰时的密度以及在防治指标之上所滞留的时间。种群在一年中能否达到防治指标与其5月末时的密度有关,因此是苹果全爪螨全年防治的关键时期。

European red mite [Panonychus ulmi (Koch)] is one key pest of apple orchards. The order of study is to know the rule of populations in a year for control the mite. The line of populations rise and fall ofP. ulmi in a year is a curved line of single peak that it is a level in both sides and rising up all of a sudden in middle part. The days lasted of infestation stage, the density of peak and the days over the control indication related with the period begening increase rapidly and the result, autor is of the opinion that, whether the populations reached the control indication or no in a year affected by the density in late May, therefore, the period is the key time to control P. ulmi.