北方果树上的红蜘蛛主要有山楂红蜘蛛和苹果红蜘蛛,其共同特点是,都在叶片反面危害,个体较小,不容易被发现,容易产生杭药性。在防治时应针对这些特点,采取相应的措施,力求达到最佳防治效果。笔者通过多年的调查和观察,认为喷药防治红蜘蛛应特别注意以下三个问题。1防治指标红蜘 Red spider on the northern fruit trees are mainly red spider hawthorn and apple red spider, the common feature is that the opposite of the leaf damage, the individual is small, not easily found, prone to Hangzhou drug resistance. In the prevention and control of these characteristics should be taken to take appropriate measures to achieve the best control effect. Through years of investigation and observation, the author thinks that spraying spider mites should pay particular attention to the following three questions. 1 control index red spider