Phytotoxicity and Growth of Coffee Plants as a Function of the Application of Herbicide 2,4-D

Abstract

Weed control in coffee is of great importance for there is a great interference, standing out the competition for water, light and nutrients. Among the control methods, chemical control is highlighted as a function of its efficiency. However, the incorrect application of herbicides may imply the occurrence of drift, resulting in damage to coffee development due to phytotoxicity. In this context, the objective of this study was to evaluate the symptoms and phytotoxicity effects caused by the herbicide 2,4-D drift on the morphological, physiological and anatomical characteristics of coffee seedlings. The experiment was carried out in a greenhouse with ‘Topázio MG1190’ coffee seedlings (<em>Coffea arabica</em> L.), planted in 11-L pots. A randomized block design with four treatments and four replicates was used. The treatments were: 0%; 10%; 25% and 50% of the recommended commercial dose of 2,4-D (2.5 L.ha<sup>-1</sup>). Each plot consisted of three plants. The evaluations were performed at 74 days after implantation. Morphological, physiological, anatomical and phytotoxicity symptoms were evaluated as a function of the simulated herbicide drift. Coffee seedlings intoxicated by the herbicide 2,4-D presented hyponastic, chlorosis, shriveling and leaf anomalies. In the orthotropic branch, bending was observed in its extension, besides thickening in the collar region; in the plagiotropic branch, cracking was observed. Herbicide drift negatively affects the development of coffee plants. The coffee physiology was affected as a function of herbicide drift, but without damage to the leaf anatomy.

Simulated Drift of Dicamba and Glyphosate on Coffee Crop

“…The plants showed characteristic changes caused by auxin, as elucidated by the abnormal increase in auxin levels in the plant tissue, leading to accelerated and disordered cell division [15]. These changes were also found by [16], who evaluated the effects of 2,4-D drift on coffee and reported leaf epinasty with deformed leaf blade length and width in the first days after application. Those findings reported curvature of the orthotropic branch in plants at an early stage of development, which was not observed in this study.…”

“…The physical classification of the size and shape of the beans was performed following the methodology described in the Brazilian Legislation [35] using a sample of 100 g of processed coffee and a set of circular (18,17,16,15,14, and 13/64ths of an inch) and oblong sieves (13,12,11,10,9, and 8/64ths of an inch). Circular sieves retained flat beans, and oblong sieves separated the "moca" beans.…”

Growth of robusta coffee after the application of herbicides to control Urochloa ruziziensis

“…Glyphosate, paraquat, diuron and oxyfluorfen are some of the main herbicides used to control weeds in coffee culture (Plese;Foloni, 2009), being an alternative for controlling U. ruziziens in intercropped systems. The application of non-selective herbicides can negatively affect the coffee seedlings due to drift, causing phytotoxicity (Voltolini et al, 2019), leading to morphological and physiological changes in the plants and, consequently, causing nutritional disorders which can be visually diagnosed through the incidence of chlorotic or diminished growth (Silva et al, 2017).…”