Bio-Herbicidal Potential of Nanoemulsions with Peppermint Oil on Barnyard Grass and Maize

Abstract

Bio-based nanoemulsions are part of green pest management for sustainable agriculture. This study assessed the physicochemical properties and the herbicidal activities of the peppermint essential oil nanoemulsions (PNs) in concentrations 1.0–10% stabilized by Eco-Polysorbate 80 on germinating seeds and young plants of maize and barnyard grass. Based on the design of experiment (DOE) results, the final nanoemulsion formulations were obtained with 1, 1.5, 2, and 5% of essential oil concentration. Biological analyses were conducted to select the most promising sample for selective control of barnyard grass in maize. Seedlings growing in the presence of PNs displayed an overall inhibition of metabolism, as expressed by the calorimetric analyses, which could result from significant differences in both content and composition of carbohydrates. Concentration–response sub estimation showed that leaf-sprayed concentration of PN causing 10% of maize damage is equal to 2.2%, whereas doses causing 50% and 90% of barnyard grass damage are 1.1% and 1.7%, respectively. Plants sprayed with PN at 5% or 10% concentration caused significant drops in relative water content in leaves and Chlorophyll a fluorescence 72 h after spraying. In summary, peppermint nanoemulsion with Eco-Polysorbate 80 at 2% concentration is a perspective preparation for selective control of barnyard grass in maize. It should be analyzed further in controlled and field conditions.

The effect of caraway oil-loaded bio-nanoemulsions on the growth and performance of barnyard grass and maize

“…The caraway essential oil was purchased from Avicenna Oil company (Wroclaw, PL). The content of the main compounds of the oil, carvone, and limonene was analyzed by a gas chromatography coupled with mass spectrometry and flame ionization detector GC–MS–FID, according to the method described by Rys et al 16 . The analyses were performed on a Trace GC Ultra coupled with a DSQII mass spectrometer (Thermo Electron, Waltham, MA, USA).…”

“…Injector and detector temperatures were 240 °C and 250 °C, respectively. The carrier gas was nitrogen at a 1.0 mL min −1 flow rate 16 .…”

“…The emulsifier was selected because it is 100% bio-based ethoxylated sorbitan ester based on a natural oleic acid. All formulations and physicochemical analyses were prepared and conducted according to the methodology described in our previous paper 16 . The first step was the preparation of the pre-emulsion mixture by combining the aqueous phase with the caraway oil and surfactant at Temperature (T) ≤ 40 °C, under magnetic stirring (v = 300 rpm).…”

“…Our previous research found that peppermint oil-loaded nanoemulsion stabilized by bio-based ethoxylated sorbitan ester of oleic acid (Eco Tween 80) and sorbitan oleate at 2% concentration can be used as a perspective preparation for selective control of barnyard grass in maize 16 . The present study used the same preparation procedure, but with caraway essential oil as the active ingredient.…”

“…Our previous research 16 , 31 – 36 has highlighted three non-destructive methods that are essential in studying plant responses to phytotoxic stress caused by herbicides or essential oils. These methods include: measurements of chlorophyll a fluorescence showing the efficiency of the photosynthetic apparatus, Fourier-transformed (FT) Raman spectroscopy allowing the examination of the chemical composition, and heat flow measured by microcalorimetry assessing the viability of seedlings.…”