Defoliation

Defoliation refers to the removal of leaves from plants, trees, or crops. It can occur naturally through seasonal leaf drop, environmental stress, or damage from pests and diseases, and it can have significant effects on photosynthesis, growth, and yield. In forestry and agriculture, defoliation is also discussed as an applied practice, where leaves are removed to influence harvest, quality, or disease management.

Natural defoliation is common in deciduous species as seasons change. Environmental stress such as drought, frost, or nutrient deficiency can cause premature leaf abscission. Insects, mites, and plant pathogens may cause defoliation by feeding on foliage or inducing tissue death. Severe or repeated defoliation may reduce photosynthetic capacity, vigor, and fruit or timber production.

Artificial defoliation uses chemical, mechanical, or biological methods. Chemical defoliants are applied to promote leaf drop or desiccation before harvest, particularly in crops like cotton and some tree fruits. They work by perturbing plant hormones or abscission layers. Mechanical methods include leaf stripping or pruning to remove foliage quickly. In viticulture and horticulture, selective defoliation is used to improve air circulation, light penetration, and disease suppression, but timing and intensity are important to minimize stress.

Defoliation carries environmental and safety considerations. Chemical defoliants can pose risks to workers, non-target organisms, and water quality; regulations govern their use and residue limits. Integrated approaches combine monitoring, choice of defoliant or method, and good agricultural practices to balance benefits and risks.