Hormonal herbicides increase the risk of phytotoxicity in cotton.

Recent cases of phytotoxicity in cotton have reignited concerns about the use of hormonal herbicides in Argentine agriculture. A survey by the Pest Management Network of Aapresid identifies damage associated with improper applications of these products.

Hormonal herbicides such as 2,4-D, dicamba, and picloram support the control of broadleaf weeds. Increased frequency of use and a wider application window, driven by tolerant biotechnologies, have increased the risk of volatilization and drift. The problem intensifies in the warmer months.

Cotton is among the most sensitive crops, even when exposed to extremely low doses. Damage at advanced stages reduces recovery capacity and increases yield losses. Sunflower, legumes, grapevines, fruit trees, vegetables, and non-tolerant soybeans also appear on the list of affected crops.

These herbicides mimic auxins and induce uncontrolled growth in susceptible plants. Symptoms include "cup-shaped" leaves, twisted petioles and stems, reduced growth, shortened internodes, flower abortion, and reproductive deformities. In cotton, the leaf malformation known as "frog's foot" or "fan-shaped" characterizes the injury, with bud abortion and capsule deformation.

Exposure to risk

The greatest risk exposure arises from applications under critical environmental conditions. High temperatures, low relative humidity, winds, and thermal inversions favor off-target movement. More volatile formulations, such as esters, increase the potential for damage, while acids and salts reduce the risk.

The rise in agricultural conflicts has spurred provincial regulations. Chaco adopted temporary restrictions. Other provinces have implemented exclusion zones, buffer zones, environmental limits, and agricultural revenue requirements. The regulatory debate remains active.

Aapresid points to application quality as the central axis of prevention. Management recommends applications only under suitable weather conditions, choosing less volatile formulations, using nozzles and pressures that reduce fine droplets, correct height, respecting safety distances, and rigorous cleaning of equipment.