Phytotoxicity assay for seed production using Brassica rapa L.

Abstract

Although pesticide drift can affect crop yield adversely, current plant testing protocols emphasize only the potential impacts on vegetative plant growth. The present study was conducted to determine whether a plant species with a short life cycle, such as Brassica rapa L. Wisconsin Fast Plants®, can be used to indicate potential effects on seed production of herbicides applied at relatively low levels (e.g., low field application rates [FAR]). The effects of ≤0.1 × FAR of aminopyralid, cloransulam, glyphosate, primisulfuron, or sulfometuron applied 14 d after emergence (DAE), were evaluated for B. rapa grown in mineral soil in pots under greenhouse conditions. Effects were expressed as the effective concentration of the herbicide producing a 25% reduction in a response (EC25) based on nonlinear regression. Brassica rapa seed dry weight was reduced by sulfometuron at an EC25 of 0.00014 × a field application rate (FAR) of 53 g active ingredient (a.i.) ha(-1), primisulfuron at 0.008 (experiment 1) or 0.0050 (experiment 2) × FAR of 40 g a.i. ha(-1), cloransulam at 0.022 × FAR of 18 g a.i. ha(-1), glyphosate at 0.0399 × FAR of 834 g a.i. ha(-1), and by aminopyralid at 0.005 × FAR of 123 g a.i. ha(-1), but only for 1 of 2 experiments. Reduced seed production occurred at less than the FAR that reduced shoot dry weight with sulfometuron and primisulfuron, whereas neither aminopyralid, cloransulam, nor glyphosate affected shoot dry weight. A short life cycle form of B. rapa could be used to indicate reduced seed production with plants grown only 1 week longer (∼35 DAE) than as the current vegetative vigor test for nontarget herbicide effects on plants.

Joint toxicity of three plant protection products to Triticum aestivum (L.) and Brassica rapa (L.)

“…In a recent study dealing with the effects of herbicide drift to B. rapa, it was concluded that concentrations below the field application rate did cause an effect on seed production but not on the shoot dry weight of this species (Olszyk et al 2010). Similar results regarding the absence of toxic effects at labeled rates of glyphosate on the shoot growth and shoot dry weight of Brassica napus were observed (Blackburn and Boutin 2003;Petersen et al 2007).…”

Individual and combined effects of herbicide tribenuron-methyl and fungicide tebuconazole on soil earthworm Eisenia fetida

“…For TBM, it has been widely reported that the yield of some sensitive crops was reduced in agricultural rotation systems due to its phytotoxicity 13 – 15 . Apart from its phytotoxic effects, there has been an increased interest of researchers in the field to investigate the impact of TBM on soil and environmental health 16 , 17 . But in case of the TEB, previous studies have shown a relative longer half-life (49–610 d) of this pesticide in the different soil environments.…”

Degradation and adsorption of tebuconazole and tribenuron-methyl in wheat soil, alone and in combination

“…Tribenuron-methyl (TBM) [methyl 2-[4-methoxy-6-methyl-1,3,5-triazin-2-yl(methyl)carbamoylsulfamoyl]benzoate] is a sulfonylurea herbicide and is widely used for controlling weed worldwide. Although TBM is regarded to be highly efficient at low dosage, it high phytotoxicity and potential pollution to soil and groundwater has been attracting extensive concern (Kotoula-Syka et al, 1993;Battaglin et al, 2000;Olszyk et al, 2010;Mehdizadeh et al, 2016). Wheat (Triticum aestivum L.) is one of the most important food crops worldwide, its yield and quality is very crucial to meet with the increasing population.…”