Response of Wheat Plants to Combinations of Herbicides with Insecticides and Fungicides

Abstract

The combination of herbicides and other pesticides can influence weed and crop management. This study aimed to evaluate the response of the combination of different herbicides with insecticides or fungicides of different chemical groups on the development and yield of wheat grains of the cultivar ORS Vintecinco. The experimental design was a randomized block design with three replications. The experiment consisted of 33 treatments, as follows: control without application and application of the herbicides 2,4-D (1,005 g a.e. ha-1), bentazon (756 g a.i. ha-1), metsulfuron-methyl (3 g a.i. ha-1), and pyroxsulam (16 g a.i. ha-1), isolated or combined with the insecticides chlorfluazuron (15 g a.i. ha-1), chlorpyrifos (720 g a.i. ha-1), deltamethrin (5 g a.i. ha-1), and methomyl (5 g a.i. ha-1) or with the fungicides azoxystrobin (100 g a.i. ha-1), carbendazim (250 g a.i. ha-1), and propiconazole (190 g a.i. ha-1). Relative tolerance (RT), shoot dry matter (SDM), yield components, and grain yield were evaluated. In general, pyroxsulam had the highest number of synergistic interactions with insecticides and fungicides, reducing RT and SDM, especially the combination pyroxsulam + chlorpyrifos due to a lower RT level (45%) and higher SDM reduction (52%). All combinations of herbicides with the insecticide chlorpyrifos and most of the combinations with the fungicide propiconazole led to a reduction of grain yield when compared to their isolated application or to control without application.

Selectivity of 2,4-D salts to barley plants applied at distinct phenological crop stages

“…In a previous study, an average increment of 3% was observed in the thousand-grain weight of barley cultivars MN610 and Crioula treated with the herbicide 2,4-D amine, compared to the witness without application of the product (Galon et al, 2014). Viecelli et al (2019) found no change in the thousand-grain weight of wheat when treated with 2,4-D amine at the third tiller emission stage.…”

Respostas morfofisiológicas de cultivares de trigo à aplicação de sais de 2,4-D amina e colina

“…Segundo Velini et al (1995) esses valores são considerados baixos. Viecelli et al (2019) observaram que a máxima fitotoxicidade ocasionada pelo 2,4-D na cultivar de trigo OR Vintecinco foi de 14,24%, sendo que a cultura conseguiu se recuperar dessa injúria, no decorrer das avaliações. O 2,4-D amina causou injúria máxima de 2,9% quando aplicado em pós-emergência do trigo e sua estatura não reduziu quando comparado a testemunha sem aplicação (Soltani et al, 2006).…”

Agronomic performance of wheat under post-emergence herbicide application

“…In addition to these factors, applying herbicides combined with insecticides or fungicides may exacerbate any injury. Viecelli et al (2019) observed a decrease in wheat plant yield with herbicide application, for 2,4-D and pyroxsulam, in combination with the insecticide chlorpyrifos, in relation to the application of herbicides alone. Hooker et al (2018) observed that herbicides, including 2,4-D, exhibited an increase in potential injury and a decrease in wheat yield when applied in combination with insecticides and/or fungicides.…”

“…The herbicides diclofop and iodosulfuron are selective for wheat, even under the water stress conditions observed in the experiment 1, while 2,4-D, clodinafop, saflufenacil, pyroxsulam and triclopyr were selective in the experiment 2. In other studies, selectivity was determined for 2,4-D (Hooker et al 2018, Viecelli et al 2019, Crose et al 2020, clodinafop (Zahid et al 2013), saflufenacil (Piasecki et al 2017), pyroxsulam (Viecelli et al 2019, diclofop (Singh et al 2020) and iodosulfuron (Piasecki et al 2017).…”