苹果锈病是一种真菌病害,也叫赤星病。主要危害苹果树的叶片和幼果,也能危害嫩梢。发病严重的苹果树常造成早期落叶、落果,导致二次萌芽,开花现象,使树势衰弱,甚至造成枝条大量枯死或整株死亡。 一、苹果锈病的主要症状 苹果树叶片受侵染后,先在正面发生橙黄色圆形病斑,病斑表面密生黄色小粒 Apple rust is a fungal disease, also known as brown spot disease. Mainly harmful to apple tree leaves and young fruit, but also can harm young shoots. Severe disease caused by the early apple trees often deciduous, fruit drop, leading to secondary germination, flowering, so that the weakness of the tree, and even cause a large number of dead branches or whole plant death. First, the main symptoms of apple rust Apple leaves affected by the infection, the first positive orange round spot on the surface, lesion surface dense yellow granules