Tolerância diferencial de clones de Eucalipto à deriva de glyphosate em condições de campo
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Universidade Federal de Viçosa
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O cultivo de eucalipto no Brasil, especialmente no estado de Mato Grosso do Sul, constitui um importante setor econômico e gerador de empregos. O manejo adequado de plantas daninhas é fundamental para a manutenção da produtividade, porém, na silvicultura, essa etapa ainda representa elevado impacto na produção de madeira, seja em função das condições inadequadas de manutenção dos equipamentos de aplicação, seja pela escassez de informações técnicas sobre os efeitos da deriva de glyphosate. Este estudo foi conduzido no município de Aparecida do Taboado, MS, em área de reforma, com espaçamento florestal de 3,4 × 2,5 m, totalizando uma área experimental de 4.998 m². O experimento foi composto por 196 plantas de cada material genético, totalizando 588 plantas no total, distribuídas em um clone de Eucalyptus urophylla (AEC0144) e dois clones híbridos Eucalyptus urograndis (A211 e A217), submetidos a quatro doses de glyphosate (0, 486, 648 e 900 g de equivalente ácido (e.a.) ha¹). A intoxicação foi avaliada aos 30 dias após a aplicação, por meio de escala visual padronizada de 0 a 100% de injúria. Nessa escala, 0% correspondeu à ausência de sintomas; de 1 a 30%, a sintomas leves, de baixa intensidade e sem prejuízos significativos ao desenvolvimento; de 31 a 60%, a sintomas moderados, com clorose e necrose parcial e impacto intermediário no crescimento; acima de 60%, a sintomas severos, com necrose extensa, deformações e comprometimento acentuado da fisiologia, embora ainda tolerados pela planta; e 100% indicou a morte da planta. Aos 30 meses após a aplicação, determinou-se a altura das plantas, circunferência à altura do peito (CAP), posteriormente convertida em diâmetro à altura do peito (DAP = CAP/), e volume com casca (VCC = × DAP2 / 40000 × Altura × 0,5), com o objetivo de quantificar o impacto da deriva de glyphosate sobre o crescimento e a produtividade das plantas. Os resultados de intoxicação apresentaram relação linear com as doses de herbicida (R² > 0,90), com níveis médios de intoxicação variando de 27% na dose mais baixa a mais de 52% na dose máxima, sem diferenças entre clones. A altura inicial das mudas variou entre 1,3 e 1,9 m; após 30 meses, as testemunhas (tratamentos 01), atingiram entre 15,8 e 17,8 m, enquanto as alturas dos tratamentos decresceram linearmente com o aumento da dose, com o clone AEC0144 apresentando maior tolerância e o A211 maior sensibilidade, com redução de até 3,2 m. O DAP das testemunhas dos clones variou entre 12,9 e 14,4 cm. O clone A217 foi o mais suscetível à deriva, apresentando redução de DAP de até 29% (4,2 cm) na dose máxima. Já os clones AEC0144 e A211 apresentaram menores reduções, próximas a 21%, reafirmando maior tolerância. Quanto ao VCC, os clones apresentaram valores iniciais entre 0,09 e 0,11 m³, com queda significativa com a dose aplicada; o clone AEC0144 destacou-se pela menor redução (0,04 m³), enquanto o A217, embora com maior VCC inicial, foi o mais impactado pela intoxicação, apresentando perdas expressivas no volume comercial (0,06 m³). Esses dados confirmam a importância da escolha criteriosa do material genético para mitigar os impactos da deriva de glyphosate, assegurando maior produtividade e sustentabilidade nos sistemas florestais. Palavras-chave: altura de planta; crescimento florestal ; deriva de aplicação; diâmetro à altura do peito ; tolerância genética; volume com casca
Eucalyptus cultivation in Brazil, especially in the state of Mato Grosso do Sul, represents an important economic sector and a major source of employment. Proper weed management is essential to maintain productivity; however, in silviculture this stage still has a strong impact on wood production, either due to inadequate maintenance of application equipment or to the lack of technical information on the effects of glyphosate drift. This study was conducted in the municipality of Aparecida do Taboado, MS, Brazil, in a reforestation area with stand spacing of 3.4 × 2.5 m, totaling an experimental area of 4,998 m². The experiment comprised 196 plants of each genetic material, totaling 588 plants, distributed in one Eucalyptus urophylla clone (AEC0144) and two Eucalyptus urophylla × Eucalyptus urograndis hybrid clones (A211 and A217), subjected to four glyphosate doses (0, 486, 648, and 900 g acid equivalent (a.e.) ha¹). Phytotoxicity was evaluated at 30 days after application using a standardized visual scale from 0 to 100% injury. In this scale, 0% corresponded to the absence of symptoms; 1 to 30% to mild symptoms, of low intensity and without significant effects on development; 31 to 60% to moderate symptoms, with evident chlorosis and partial necrosis and an intermediate impact on growth; values above 60% to severe symptoms, with extensive necrosis, deformities and marked impairment of plant physiology, although still tolerated by the plant; and 100% indicated plant death. At 30 months after application, plant height, circumference at breast height (CBH), later converted to diameter at breast height (DBH = CBH/), and commercial stem volume with bark (VCC = × DBH²/40000 × height × 0.5) were determined in order to quantify the impact of glyphosate drift on plant growth and productivity. Phytotoxicity results showed a linear relationship with herbicide dose (R² > 0.90), with mean injury levels ranging from 27% at the lowest dose to more than 52% at the highest dose, with no differences among clones. Initial seedling height ranged from 1.3 to 1.9 m; after 30 months, untreated controls reached 15.8 to 17.8 m, whereas plant height in the treated plots decreased linearly with increasing dose. Clone AEC0144 showed greater tolerance and A211 greater sensitivity, with height reductions of up to 3.2 m. DBH of the control plants ranged from 12.9 to 14.4 cm. Clone A217 was the most susceptible to drift, showing DBH reductions of up to 29% (4.2 cm) at the highest dose, whereas clones AEC0144 and A211 exhibited smaller reductions, close to 21%, confirming their higher tolerance. Regarding VCC, clones showed initial values between 0.09 and 0.11 m³, with significant decreases as the dose increased; clone AEC0144 had the smallest reduction (0.04 m³), whereas A217, although presenting the highest initial VCC, was the most affected by phytotoxicity, with expressive losses in commercial volume (0.06 m³). These results confirm the importance of careful selection of genetic material to mitigate the impacts of glyphosate drift, ensuring higher productivity and sustainability in forest production systems. Keywords: plant height; forest growth; spray drift; diameter at breast height; genetic tolerance; stem volume with bark
Eucalyptus cultivation in Brazil, especially in the state of Mato Grosso do Sul, represents an important economic sector and a major source of employment. Proper weed management is essential to maintain productivity; however, in silviculture this stage still has a strong impact on wood production, either due to inadequate maintenance of application equipment or to the lack of technical information on the effects of glyphosate drift. This study was conducted in the municipality of Aparecida do Taboado, MS, Brazil, in a reforestation area with stand spacing of 3.4 × 2.5 m, totaling an experimental area of 4,998 m². The experiment comprised 196 plants of each genetic material, totaling 588 plants, distributed in one Eucalyptus urophylla clone (AEC0144) and two Eucalyptus urophylla × Eucalyptus urograndis hybrid clones (A211 and A217), subjected to four glyphosate doses (0, 486, 648, and 900 g acid equivalent (a.e.) ha¹). Phytotoxicity was evaluated at 30 days after application using a standardized visual scale from 0 to 100% injury. In this scale, 0% corresponded to the absence of symptoms; 1 to 30% to mild symptoms, of low intensity and without significant effects on development; 31 to 60% to moderate symptoms, with evident chlorosis and partial necrosis and an intermediate impact on growth; values above 60% to severe symptoms, with extensive necrosis, deformities and marked impairment of plant physiology, although still tolerated by the plant; and 100% indicated plant death. At 30 months after application, plant height, circumference at breast height (CBH), later converted to diameter at breast height (DBH = CBH/), and commercial stem volume with bark (VCC = × DBH²/40000 × height × 0.5) were determined in order to quantify the impact of glyphosate drift on plant growth and productivity. Phytotoxicity results showed a linear relationship with herbicide dose (R² > 0.90), with mean injury levels ranging from 27% at the lowest dose to more than 52% at the highest dose, with no differences among clones. Initial seedling height ranged from 1.3 to 1.9 m; after 30 months, untreated controls reached 15.8 to 17.8 m, whereas plant height in the treated plots decreased linearly with increasing dose. Clone AEC0144 showed greater tolerance and A211 greater sensitivity, with height reductions of up to 3.2 m. DBH of the control plants ranged from 12.9 to 14.4 cm. Clone A217 was the most susceptible to drift, showing DBH reductions of up to 29% (4.2 cm) at the highest dose, whereas clones AEC0144 and A211 exhibited smaller reductions, close to 21%, confirming their higher tolerance. Regarding VCC, clones showed initial values between 0.09 and 0.11 m³, with significant decreases as the dose increased; clone AEC0144 had the smallest reduction (0.04 m³), whereas A217, although presenting the highest initial VCC, was the most affected by phytotoxicity, with expressive losses in commercial volume (0.06 m³). These results confirm the importance of careful selection of genetic material to mitigate the impacts of glyphosate drift, ensuring higher productivity and sustainability in forest production systems. Keywords: plant height; forest growth; spray drift; diameter at breast height; genetic tolerance; stem volume with bark
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SANTOS, Jerffson da Silva. Tolerância diferencial de clones de Eucalipto à deriva de glyphosate em condições de campo. 2025. 28 f. Dissertação (Mestrado Profissional em Defesa Sanitária Vegetal) - Universidade Federal de Viçosa, Viçosa. 2025.