Herbicide Injury
Herbicide exposure (chemical injury)
Overview
Herbicide injury results when plants contact herbicides at unintended rates, through drift, vapor movement, contaminated mulch or manure, or misapplication. Growth-regulator herbicides (such as those related to 2,4-D and dicamba) cause twisting and cupping on broadleaf plants far from the treated area. Soil residuals can affect subsequent plantings. Distinguishing herbicide injury from virus or nutrient problems prevents wasted sprays and points you toward the real source: application practices, neighbors, or contaminated inputs.
Symptoms
Growth-regulator injury produces cupped, strapped, or fern-like leaves, twisted petioles, and distorted new growth. Contact herbicides cause speckled burn or bleached spots. Root-uptake residuals may stunt seedlings uniformly across a bed. Tomato, grape, and bean are common drift indicators. Symptoms often appear suddenly across many species after a spray day with wind. Veins may yellow or parallel leaf strapping may appear on new flush.
Environmental Conditions
Variable
Prevention
Do not spray on windy days; use coarse droplets and low boom heights if you must apply lawn herbicides near gardens. Create buffer plantings and communicate with neighbors about drift-sensitive crops. Use herbicide-free mulches and manures from trusted sources. Read labels for plant-back intervals. Prefer mechanical and cultural weed control in mixed vegetable and food-forest systems. Keep a spray log so you can correlate injury events with applications.
Management
Stop further exposure and irrigate lightly to dilute soil residues if appropriate for the product type. Do not apply additional pesticides that add stress. Prune off the worst distorted growth after plants stabilize, and support recovery with water and modest fertility. Severely injured annuals may need replanting. Identify the herbicide family if possible so you know whether activated carbon, time, or tillage helps before replanting. Avoid composting obviously contaminated clippings into sensitive garden beds.