Differential Tolerance of Clones of Eucalyptus grandis Exposed to Drift of the Herbicides Carfentrazone-Ethyl and Glyphosate

Abstract

Drift of the herbicides carfentrazone-ethyl and glyphosate may affect the initial growth of eucalyptus. This study aimed to assess the effect of carfentrazone-ethyl and glyphosate drift on photosynthesis, leaf morphoanatomy, and initial growth of two clones of Eucalyptus grandis. Two experiments were carried out in a 2 x 4 factorial scheme, in which factor 1 was represented by two clones of E. grandis and factor 2 by four herbicide underdoses (control, 86.4 g a.e. ha-1 of glyphosate, 3.0 g a.e. ha-1 of carfentrazone-ethyl, and the mixture of 86.4 g a.e. ha-1 of glyphosate + 3.0 g a.e. ha-1 of carfentrazone-ethyl). Herbicide application was carried out by simulating the drift in the lower third of seedling canopy. Assessments were performed 23 days after herbicide application. Both clones presented morphoanatomical changes such as erosion of epicuticular waxes and degeneration of epidermal and parenchymal cells, especially when exposed to carfentrazone-ethyl underdose or its mixture with glyphosate. The clone CLR 383 was the most affected by the tested herbicides and presented the highest injury, lowest initial growth, lowest dry matter, and highest reduction of photosynthetic rate when treated with herbicide mixture, followed by carfentrazone-ethyl and glyphosate underdoses. The initial growth, dry matter, and photosynthesis of the clone CLR 384 were not affected by the carfentrazone-ethyl underdose. Thus, both herbicides applied in isolation or in a mixture reduced the initial growth, dry matter, and photosynthesis of eucalyptus.

Hydrogen peroxide, superoxide, lipid peroxidation and membrane damage in leaves of the tree Prosopis nigra (Fabaceae) under simulated glyphosate drift

“…Similarly, in Eucalyptus urograndis clones CLR383 and CLR384, 86.4 g a.e. ha -1 glyphosate produced a decrease of 27 and 32 % in A with respect to the control, respectively (Santos, Tuffi-Santos, Alfenas, Faria, & Sant'anna-Santos, 2019). In Olea europea, glyphosate did not affect net photosynthesis values, stomatal conductance or chlorophyll a fluorescence emission variables (Cañero et al, 2011).…”

Safety of genetically modified glyphosate-tolerant eucalyptus designed for integrated weed management

“…Consequently, these HT GM eucalyptus varieties can be confidently utilized for wood production. However, eucalyptus exhibits a high sensitivity to glyphosate (Cerveira Junior et al, 2020;Pereira et al, 2013) and even slight herbicide drift (2.4% of the recommended 1.8 Kg a.e/ha application dose) during application can cause significant damage to young eucalyptus plantlets, leading to a substantial decline in yield (Meloni, Martínez, 2021;Santos et al, 2015;Santos et al, 2019). To address this issue, Suzano and its subsidiary FuturaGene have developed genetically modified (GM) glyphosate-tolerant eucalyptus varieties.…”

Weed Coexistence in Eucalyptus Hybrid Stands Decreases Biomass and Nutritional Efficiency Mid-Rotation

“…Many studies have analyzed the efficiency of different herbicides in weed control or their drift and the impact on eucalyptus growth [7,12,13]. Other studies have evaluated plant spacing as a form of control [7,14].…”