Resposta fisiológica de alface a subdoses de maturadores utilizados em cana-de-açucar
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Data
2019-08-02
Autores
Rodrigues, Juliana de Souza
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Universidade Estadual Paulista (Unesp)
Resumo
É prática comum durante o cultivo da cana-de-açúcar o uso de maturadores de forma antecipar a colheita. No entanto, considerando que pode haver cultivos próximos, como o de hortaliças, é importante ressaltar os cuidados necessários quando dá aplicação destes produtos, que é realizada por via aérea, a fim de evitar a deriva. Culturas sensíveis, como a da alface, podem sofrer efeitos deletérios. Sendo assim, objetivou-se com este trabalho avaliar o efeito da deriva dos maturadores glyphosate, trinexapac-ethyl e sulfometuron comumente utilizados em cana-de-açúcar no crescimento da alface ‘Lucy Brown’ e ‘Vanda’. O experimento foi instalado em ambiente aberto do Laboratório de Plantas Daninhas (LAPDA), UNESP/FCAV nos meses de outubro e novembro. Mudas de alface foram transplantadas para vaso com capacidade para 5 L, sendo cada planta a parcela experimental. O experimento foi constituído de 15 tratamentos estabelecidos no delineamento em blocos casualizados em esquema fatorial 3x5, com cinco repetições. O primeiro fator correspondeu aos maturadores e o segundo às subdoses, de forma a simular a deriva, sendo essas de 0, 3%, 6%, 9% e 12% da dose recomendada de cada produto, sendo aplicados quando as mudas apresentavam ao início da formação da cabeça, para a cultivar Lucy Brown e o estádio de 6 a 7 folhas para a cultivar Vanda. Após aplicação, as avaliações ocorreram aos 5, 10, 15 e 20 dias após aplicação (DAA). Foram realizadas avaliações visuais, com base na escala EWRC (1964), teor de clorofilas, eficiência quântica do fotossistema II, número de folhas, massa fresca e massa seca. Para a cultivar ‘Lucy Brown’ todos os produtos testados resultaram em danos visuais, redução no teor de clorofila aos 15 dias após aplicação, sem afetar a fluorescência da clorofila a, bem como redução da massa fresca e seca aos 20 dias após aplicação. Para a cultivar ‘Vanda”, sulfometuron methyl e trinexapac ethyl causaram danos visuais permanentes, enquanto para o glyphosate houve posterior recuperação das plantas. Os produtos reduziram os teores de clorofila, causaram alterações no fotossistema II, reduzindo a massa seca sem alterar número de folhas e massa fresca. Sendo assim, é possível concluir que já a partir de 3% da dose recomendada para maturação da cana-de-açúcar, o trinexapac-ethyl e sulfumeturon methyl podem acarretar em grandes prejuízos à cultura da alface ‘Lucy Brown’ e ‘Vanda’, quando aplicados início da formação da cabeça e no estádio de 6 a 7 folhas, respectivamente, enquanto o glyphosate até a dose de 12% da dose recomendada não causou danos irreversíveis à cultura
It is common practice during the cultivation of sugarcane to use ripeners in order to anticipate the harvest. However, considering that there may be crops nearby, such as vegetables, it is important to emphasize the necessary care when applying these products, which is carried out by air, in order to avoid drifting. Sensitive crops, such as lettuce, can suffer deleterious effects. Therefore, the aim of this work was to evaluate the effect of the glyphosate, trinexapac-ethyl and sulfometuron ripening effects commonly used in sugarcane on 'Lucy Brown' and 'Vanda' lettuce growth. The experiment was installed in an open environment at the Laboratory of Weeds (LAPDA), UNESP / FCAV in the months of October and November. Lettuce seedlings were transplanted to a 5 L pot, each plant being the experimental plot. The experiment consisted of 15 treatments established in a randomized complete block design in a 3x5 factorial scheme, with five replications. The first factor corresponded to the ripeners and the second to the subdoses, in order to simulate the drift, being 0, 3%, 6%, 9% and 12% of the recommended dose of each product, being applied when the seedlings presented at the beginning of the head formation, for the Lucy Brown cultivar and the 6 to 7 leaf stage for the Vanda cultivar. After application, the evaluations occurred at 5, 10, 15 and 20 days after application (DAA). Visual evaluations were performed based on the EWRC scale (1964), chlorophyll content, quantum efficiency of photosystem II, number of leaves, fresh mass and dry mass. For 'Lucy Brown' all products tested resulted in visual damage, reduction in chlorophyll content at 15 days after application, without affecting chlorophyll a fluorescence, as well as reduction of fresh and dry mass at 20 days after application. For the 'Vanda' cultivar, sulfometuron methyl and trinexapac ethyl caused permanent visual damages, whereas for glyphosate there was later recovery of the plants. The products reduced chlorophyll content, caused changes in photosystem II, reducing the dry mass without changing leaves number and fresh mass. Thus, it is possible to conclude that trinexapac-ethyl and sulfometuron methyl can lead to a great damage to the 'Lucy Brown' and 'Vanda' lettuce cultivars, from 3% of the recommended dose for sugarcane maturation, when applied early head formation and at the stage of 6 to 7 leaves respectively while glyphosate up to the 12% dose of the recommended dose did not cause irreversible damage to the crop.
It is common practice during the cultivation of sugarcane to use ripeners in order to anticipate the harvest. However, considering that there may be crops nearby, such as vegetables, it is important to emphasize the necessary care when applying these products, which is carried out by air, in order to avoid drifting. Sensitive crops, such as lettuce, can suffer deleterious effects. Therefore, the aim of this work was to evaluate the effect of the glyphosate, trinexapac-ethyl and sulfometuron ripening effects commonly used in sugarcane on 'Lucy Brown' and 'Vanda' lettuce growth. The experiment was installed in an open environment at the Laboratory of Weeds (LAPDA), UNESP / FCAV in the months of October and November. Lettuce seedlings were transplanted to a 5 L pot, each plant being the experimental plot. The experiment consisted of 15 treatments established in a randomized complete block design in a 3x5 factorial scheme, with five replications. The first factor corresponded to the ripeners and the second to the subdoses, in order to simulate the drift, being 0, 3%, 6%, 9% and 12% of the recommended dose of each product, being applied when the seedlings presented at the beginning of the head formation, for the Lucy Brown cultivar and the 6 to 7 leaf stage for the Vanda cultivar. After application, the evaluations occurred at 5, 10, 15 and 20 days after application (DAA). Visual evaluations were performed based on the EWRC scale (1964), chlorophyll content, quantum efficiency of photosystem II, number of leaves, fresh mass and dry mass. For 'Lucy Brown' all products tested resulted in visual damage, reduction in chlorophyll content at 15 days after application, without affecting chlorophyll a fluorescence, as well as reduction of fresh and dry mass at 20 days after application. For the 'Vanda' cultivar, sulfometuron methyl and trinexapac ethyl caused permanent visual damages, whereas for glyphosate there was later recovery of the plants. The products reduced chlorophyll content, caused changes in photosystem II, reducing the dry mass without changing leaves number and fresh mass. Thus, it is possible to conclude that trinexapac-ethyl and sulfometuron methyl can lead to a great damage to the 'Lucy Brown' and 'Vanda' lettuce cultivars, from 3% of the recommended dose for sugarcane maturation, when applied early head formation and at the stage of 6 to 7 leaves respectively while glyphosate up to the 12% dose of the recommended dose did not cause irreversible damage to the crop.
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Herbicidas, Lactuca sativa, Saccharum spp, Herbicides