Which of the following is NOT a symptom of a vascular wilt disease?

The answer identifies "leaf buds are distorted" as not being a symptom of vascular wilt disease, which is appropriate given the characteristics of such diseases. Vascular wilt diseases primarily cause symptoms related to the movement of water and nutrients within the plant, affecting its vascular system.

Symptoms such as discolored streaks in the wood of affected branches indicate the presence of pathogens that block vascular tissues. This blockage leads to a lack of water supply to certain parts of the plant, typically resulting in one side being more affected than the other and causing individual limbs and branches to wilt and die back.

In contrast, distorted leaf buds are generally more indicative of other types of plant disorders, such as physiological stress or insect damage, rather than vascular wilt diseases. Therefore, identifying distorted leaf buds as a symptom of vascular wilt misaligns with the established effects of these diseases, which center around wilting and dieback associated with vascular impairment rather than developmental abnormalities like bud distortion.