The Herbicidal Potential of Different Pelargonic Acid Products and Essential Oils against Several Important Weed Species

Abstract

There is growing consideration among farmers and researchers regarding the development of natural herbicides providing sufficient levels of weed control. The aim of the present study was to compare the efficacy of four different pelargonic acid products, three essential oils and two natural products’ mixtures against L. rigidum, A. sterilis and G. aparine. Regarding grass weeds, it was noticed at 7 days after treatment that PA3 treatment (pelargonic acid 3.102% w/v + maleic hydrazide 0.459% w/v) was the least efficient treatment against L. rigidum and A. sterilis. The mixture of lemongrass oil and pelargonic acid resulted in 77% lower dry weight for L. rigidum in comparison to the control. Biomass reduction reached the level of 90% as compared to the control in the case of manuka oil and the efficacy of manuka oil and pelargonic acid mixture was similar. For sterile oat, weed biomass was recorded between 31% and 33% of the control for lemongrass oil, pine oil, PA1 (pelargonic acid 18.67% + maleic hydrazide 3%) and PA4 (pelargonic acid 18.67%) treatments. In addition, the mixture of manuka oil and pelargonic acid reduced weed biomass by 96% as compared to the control. Regarding the broadleaf species G. aparine, PA4 and PA1 treatments provided a 96–97% dry weight reduction compared to the corresponding value recorded for the untreated plants. PA2 (pelargonic acid 50% w/v) treatment and the mixture of manuka oil and pelargonic acid completely eliminated cleaver plants. The observations made for weed dry weight on the species level were similar to those made regarding plant height values recorded for each species. Further research is needed to study more natural substances and optimize the use of natural herbicides as well as natural herbicides’ mixtures in weed management strategies under different soil and climatic conditions.

Capped polyethylene glycol esters of fatty acids as novel active principles for weed control

“…Thus, to prcevent external factors from affecting the efficacy of the test preparations, prior trials on climate conditions, weed size and application rate were performed (data not shown). Overall, the findings were consonant with published studies 14–17 . Accordingly, the trials were done under moderate climate conditions (approximately 23/18°C day/night), and on medium sized (18–20 cm) weeds.…”

“…It showed the best weed control (Figures 2–5) and does not need any formulation (Table 2), being relatively easy to co‐formulate with other herbicidal substances 51 . Co‐formulation should be further studied, for example A3 and the triketone leptospermone, which showed good efficacy in combination with PA in the spray tank 14 . The biological outcome for A3 is equal, or even superior, to the PA herbicide applied (Figure 6), but this outstanding efficacy was achieved with 50 L of product and a water volume of 450 L ha −1 , a reduction of 80 L ha −1 of product and 420 L ha −1 of water in comparison with the benchmark label recommendations.…”

“…Some new active compounds have been used directly in weed control or as leads for new herbicides, being degradable, non‐toxic and produced by or aligned with nature 12,13 . Many substances derived from natural products like triketones or essentials oils have proven herbicidal potential although only a few have been commercialized 13,14 . Especially needed are fast‐acting and resistance‐breaking contact herbicides, particularly since the loss of previous products such as paraquat.…”

Screening glyphosate-alternative weed control options in important perennial crops

“…Pelargonic acid (two times) was characterized by lower efficacy on E. crus-galli. This result agrees with the findings of Travlos et al (2020b), who reported low efficacy of pelargonic acid on grass weeds. Mowing did not reduce E. crus-galli biomass compared with the untreated in both years and evaluations.…”

“…As for C. album, the double pelargonic acid application reduced its dry weight compared with barley residues and the untreated in both evaluations of 2018 to 2019 and 2019 to 2020 (Figure 1B). The efficacy of pelargonic acid on broadleaf weeds has recently been recently highlighted (Travlos et al 2020b). Mowing reduced C. album dry weight compared with cover crop residues and the untreated in both years and evaluations.…”