Sensibility of plant species to herbicides aminocyclopyrachlor and indaziflam

Abstract

-Aminocyclopyrachlor and indaziflam are under development in Brazil and there is no information about their behavior in Brazilian soils. This study aimed to evaluate the sensitivity of plant species to these new molecules, trying to select plants that can be used as bioindicators for testing the behavior of these herbicides in the soil. Two experiments were conducted, one for each herbicide. The treatments were arranged in a 8 x 6 factorial design, the factors being represented by eight species used as bioindicators -cotton, maize, soybean, sorghum, sunflower, millet, cucumber and beet, and six doses of herbicides (aminocyclopyrachlor -0, 10 , 20, 30 , 40 and 50 g ha ). Among the species studied, soybean and beet were quite sensitive to the two new herbicide molecules, being great alternatives for bioassays in order to detect low concentrations of aminocyclopyrachlor and indaziflam in the soil.Keywords: beet, bioassay, I 50 , soybean. -algodão, milho, soja, sorgo, girassol, milheto, pepino e beterraba e seis doses dos herbicidas (aminocyclopyrachlor -0; 10; 20; 30; 40 RESUMO -O aminocyclopyrachlor e indaziflam encontram-se em fase de desenvolvimento no Brasil e não existem informações a respeito do comportamento destes em solos brasileiros. Este trabalho teve como objetivo avaliar a sensibilidade de espécies vegetais à estas novas moléculas, buscando selecionar plantas que possam ser utilizadas como bioindicadores em ensaios de comportamento destes herbicidas no solo. Foram conduzidos dois experimentos um para cada herbicida. Os tratamentos foram dispostos em esquema fatorial 8 x 6, sendo os fatores representados por oito espécies utilizadas como bioindicadoras

Saflufenacil and indaziflam herbicide effects on agricultural crops and microorganisms

“…The sunflower plants presented high phytotoxicity values that ranged from 60% (sowing between 40 and 60 DAA) to 80% (sowing at the other times) ( Figure 3C). These results are similar to those found by Guerra et al (2014), who showed that sunflower was the most indaziflam-tolerant species of those evaluated, presenting only a slight decrease in the fresh weight of roots. Furthermore, even at the highest dose tested (100 g ha indaziflam on sunflower, cotton, maize, soybean, millet, cucumber, beet and sorghum, observed that all the species studied were sensitive to indaziflam.…”

“…For example, the phytotoxicity was 70% at 60 DAA, and a direct positive relationship existed between increased dose and plant phytotoxicity ( Figure 3A). These results corroborate those of Guerra et al (2014), who reported that not only soybean but also sorghum, millet, cucumber and beet showed an indaziflam dose below 5 g ha -1 that caused 50% injury to the plants (I 50 dose), with the dose commonly used in countries where this herbicide has already been registered 20 times higher than 5 g ha -1…”

“…In contrast, sorghum, millet, cucumber and beet did not emerge even in soil treated with the lowest indaziflam dose (20 g ha -1 ) (Guerra et al, 2014).…”

“…The authors concluded that most of the species tested were highly sensitive to indaziflam (Guerra et al, 2014).…”

“…According to Guerra et al (2014), studies conducted Torres et al 873 during the initial development of maize, millet, sorghum, soybean, sunflower, cotton, beet and cucumber crops indicated that all the species were sensitive to soilapplied indaziflam in the field. The only symptom observed in the different species after planting in soil containing this herbicide was the nonemergence of seedlings, except for sunflower.…”