Biotic stress refers to the negative impact on plants caused by living organisms, such as pests, diseases, and weeds. These organisms compete with plants for resources like nutrients, water, and light, which can hinder their growth and development. Common examples of biotic stressors include insects like aphids, fungi like powdery mildew, and invasive plants like kudzu. Plants have developed various defense mechanisms to cope with biotic stress, including physical barriers like thorns and chemical responses that deter pests. Understanding biotic stress is crucial for agriculture, as it helps farmers implement effective management strategies to protect crops and ensure food security.