Improved herbicide selectivity in tomato by safening action of benoxacor and fenclorim

Abstract

Safeners have been widely used to reduce phytotoxicity to crops, thus serving as an alternative weed control strategy. Benoxacor and fenclorim safeners have the potential to protect plants from herbicide phytotoxicity by increasing glutathione S-transferase (GST) activity within the plant. The study aimed to evaluate the safening effect of benoxacor and fenclorim on tomato against selected herbicides applied POST. The experiment was conducted in a greenhouse in a completely randomized designed with four replications in a 9 × 3 factorial scheme, where Factor A consisted of eight herbicides including a nontreated control, and Factor B consisted of two safeners including a nontreated control. The herbicide treatments were sulfentrazone (0.220 kg ai ha−1), fomesafen (0.280 kg ai ha−1), flumioxazin (0.070 kg ai ha−1), linuron (1.200 kg ai ha−1), metribuzin (0.840 kg ai ha−1), pyroxasulfone (0.220 kg ai ha−1), and bicyclopyrone (0.040 kg ai ha−1). Safener treatments consisted of benoxacor (0.67 g L−1) and fenclorim (10 µM). Tomato seeds were immersed in safener solution before sowing and herbicides were applied when tomato plants were at the 3-leaf stage, or 25 days after sowing. Visible injury was scored at 3, 7, 14, and 21 d after application (DAA), and shoot biomass was recorded 21 DAA. Seed treatment with fenclorim reduced injury caused by imazamox and bicyclopyrone by 5.5 and 1.3 times, respectively, whereas benoxacor reduced the injury from bicyclopyrone 1.3 times. In addition, tomato plants pretreated with fenclorim showed a lesser reduction in biomass after application of imazamox, fomesafen, and metribuzin, whereas plants pretreated with benoxacor showed lesser biomass reduction after metribuzin application. Thus, the use of safeners promotes greater crop selectivity, allowing the application of herbicides with different mechanisms of action on the crop.

Selectivity of herbicides isolated and/or with the addition of adjuvants for Physalis angulata crop

“…The mixture of fluazifop-p-butyl with fomesafen with and without adjuvant caused a moderate intoxication to crop plants (Figures 1A and 2A) and the number of fruits did not differ from the control with weeding (Table 3). The intoxication observed in plants from experiments I and II was probably due to fomesafen, because, when applied alone, Castro et al (2020) observed reductions of up to 62% in tomato plants, compared to the control without herbicides. When there is a mixture of fluazifop-p-butyl + fomesafen, the formulation acquires a broad spectrum of weed control (Silva & Silva, 2007), which may be a viable alternative for the cultivation of P. angulata, insofar as future works indicate the possibility of a later application compared to those used in this experiment, since the results in field proved to be promising (Table 3).…”

Luminescence imaging of leaf damage induced by lipid peroxidation products and its modulation by β‐cyclocitral

“…β‐CC itself has a low toxicity causing little damage to leaves (Figure 8C). Thus, the action of β‐CC resembles the function of herbicide safeners, that is, chemicals of low toxicity able to induce enzymes involved in the detoxification and metabolization of herbicides (Castro et al, 2020; Riechers et al, 2010). Herbicide safeners offer important agricultural perspectives in alternative weed control strategies to increase herbicide selectivity in crops.…”

Research Progress on the Action Mechanism of Herbicide Safeners: A Review

“…GSH, an essential substance in the metabolic detoxification process, conjugates with xenobiotics, such as pesticides or heavy metals, spontaneously or catalyzed by GSTs to inactivate them. 46 This process is presumed to be requisite for the metabolite's transport into the vacuole (phase III) and possible further breakdown within the vacuole (phase IV). GSTcatalyzed GSH conjugation is essential for removing toxic substances from the cytosol and preventing their interaction with targets.…”