What is the effect of fertilizer toxicity on plant health?

Fertilizer toxicity can have a significant negative impact on plant health, making plants more susceptible to biotic diseases. This occurs when excessive fertilizer application leads to an imbalance of nutrients and stress within the plant. High levels of nutrients can result in a condition known as nutrient toxicity, which can weaken a plant’s natural defenses, making it more vulnerable to pathogens such as fungi, bacteria, and viruses.

When plants are overloaded with nutrients, particularly nitrogen, it may promote lush, rapid growth, but this growth can be superficial and not robust enough to withstand environmental stresses or attack from pests and diseases. Under this stress, the plant may not produce sufficient secondary metabolites—substances that are often important in defending against pathogens.

As a result, while some might assume that fertilization leads to healthier plants, inappropriate or excessive fertilization can create an environment that fosters disease susceptibility, thus negatively affecting overall plant health.