Apple Root and Collar Rot

Triệu chứng

First symptoms on apple and pear trees appear on foliage, and are characterized by poor terminal growth and small chlorotic, wilting leaves. Trees may also have a stunted aspect. By this time the development of the rotting in roots and crown is already in a well advanced stage. Upon removal of the bark, the internal tissues show a well-defined areas with a orange- to red-brown tinge. As the disease progresses, they enlarge and turn brown. The necrosis or rotting of the vascular tissues limits the supply of nutrients to the whole plant. General stress symptoms such as pale, wilting leaves and leaf drop ensue and stunted plant growth are due to that. Trees decline over several seasons and eventually die. Fruit rot can also occur, showing as dark-brown lesions that can affect the entire fruit. Fruit trees are susceptible to the rotting at different stages of maturation.