Seletividade de herbicidas pré-emergentes em espécies de crotalária

Abstract

Resumo – As crotalárias são frequentemente utilizadas como plantas de cobertura no manejo agrícola. Entretanto, não há herbicidas registrados para a cultura, para realizar o manejo de plantas daninhas. Diante disto, este trabalho objetivou avaliar a seletividade de quatro herbicidas pré-emergentes em quatro espécies de crotalárias. Foi instalado um experimento em campo com quatro herbicidas pré-emergentes (trifluralina, clomazone, sulfentrazone, diclosulam) utilizando quatro espécies de crotalária (C. spectabilis, C. juncea, C. breviflora e C. ochroleuca). Utilizou-se um delineamento experimental de blocos casualizados, com 5 tratamentos em 4 repetições. Avaliou-se a emergência, a fitotoxicidade aos 7, 14, 21,28 e 35 dias após a aplicação e a massa seca de raiz e parte aérea. Os resultados obtidos sobre a emergência e seletividade de herbicidas em diferentes espécies de crotalária demonstraram respostas variadas para cada herbicida e espécie avaliada. O clomazone se destacou como seletivo para C. juncea e C. breviflora, enquanto o sulfentrazone apresentou maior seletividade para C. breviflora. Já o herbicida trifluralina resultou em menor emergência apenas de C. spectabilis. Todos os herbicidas apresentaram fitotoxicidade menor que 30%, demostrando a seletividade dos herbicidas utilizados para as espécies.

Abstract – Crotalaria are often used as cover crops in agricultural management. However, there are no registered herbicides for the crop to manage weeds. Therefore, this work aimed to evaluate the selectivity of four pre-emergent herbicides in four species of crotalaria. A field experiment was installed with four pre-emergent herbicides (trifluralin, clomazone, sulfentrazone, diclosulam) using four species of crotalaria (C. spectabilis, C. juncea, C. breviflora and C. ochroleuca). An experimental design of randomized blocks was used, with 5 treatments and 4 replications. Emergence, root and shoot dry mass and phytotoxicity were evaluated at 7, 14, 21, 28 and 35 DAA. The results obtained on the emergence and selectivity of herbicides in different sunn hemp species showed varied responses for each herbicide and evaluated species. Clomazone stood out as selective for C. juncea and C. breviflora, while Sulfentrazone showed greater selectivity for C. breviflora. The herbicide Trifluralin, on the other hand, showed less emergence only in C. spectabilis. All herbicides showed phytotoxicity lower than 30%, demonstrating the selectivity of the herbicides used for the species.

Crotalaria are often used as cover crops in agricultural management. However, there are no registered herbicides for the crop to manage weeds. Therefore, this work aimed to evaluate the selectivity of four pre-emergent herbicides in four species of crotalaria. A field experiment was installed with four pre-emergent herbicides (trifluralin, clomazone, sulfentrazone, diclosulam) using four species of crotalaria (C. spectabilis, C. juncea, C. breviflora and C. ochroleuca). An experimental design of randomized blocks was used, with 5 treatments and 4 replications. Emergence, root and shoot dry mass and phytotoxicity were evaluated at 7, 14, 21, 28 and 35 DAA. The results obtained on the emergence and selectivity of herbicides in different sunn hemp species showed varied responses for each herbicide and evaluated species. Clomazone stood out as selective for C. juncea and C. breviflora, while Sulfentrazone showed greater selectivity for C. breviflora. The herbicide Trifluralin, on the other hand, showed less emergence only in C. spectabilis. All herbicides showed phytotoxicity lower than 30%, demonstrating the selectivity of the herbicides used for the species.