Microencapsulated Caraway Essential Oil Affects Initial Growth of Maize Cultivars

Abstract

Caraway (Carum carvi L.) essential oil is a candidate for botanical herbicides. A hypothesis was formulated that the sand-applied maltodextrin-coated caraway oil (MCEO) does not affect the growth of maize (Zea mays L.). In the pot experiment, pre-emergence application of five doses of MCEO was tested on four maize cultivars up to the three-leaf growth stage. The morphological analyses were supported by the measurements of relative chlorophyll content (SPAD), two parameters of chlorophyll a fluorescence, e.g., Fv/Fm and Fv/F0, and fluorescence emission spectra. The analyzed MCEO contained 6.5% caraway EO with carvone and limonene as the main compounds, constituting 95% of the oil. The MCEO caused 7-day delays in maize emergence from the dose of 0.9 g per pot (equal to 96 g m−2). Maize development at the three-leaf growth stage, i.e., length of roots, length of leaves, and biomass of shoots and leaves, was significantly impaired already at the lowest dose of MCEO: 0.4 g per pot, equal to 44 g m−2. A significant drop of both chlorophyll a fluorescence parameters was noted, on average, from the dose of 0.7 g per pot, equal to 69 g m−2. Among the tested cultivars, cv. Rywal and Pomerania were less susceptible to the MCEO compared to the cv. Kurant and Podole. In summary, maize is susceptible to the pre-emergence, sand-applied MCEO from the dose of 44 g m−2.

Maltodextrin-Coated Peppermint and Caraway Essential Oils Effects on Soil Microbiota

“…The microcapsules with maltodextrin as a carrier and caraway or peppermint oil as a core were purchased from a commercial producer (Hoffmann Aroma, Zamysłowo, Poland). The oil content and chemical composition were characterized and presented in our previous work [ 13 , 15 ] and are summarized in Table 3 .…”

“…Both peppermint and caraway oil display several agro-biological activities [ 11 , 12 ] and are potential sources of botanical pesticides. Some authors accentuate soil application of these oils as microcapsules for effective pest and weed control [ 13 , 14 , 15 , 16 ]. Peppermint ( Mentha piperita L.) is a perennial herb from the Lamiaceae family [ 17 ], originating from the Mediterranean region but cultivated all over the world [ 18 ].…”

Phytotoxic Effect of Caraway Essential Oil and Its Main Compounds against Germination of Spring Wheat, Wild Oat and Chamomile

“…Essential oils of plant origin show phytotoxic properties that can be used to produce socalled botanical herbicides, i.e., substances of plant origin for weed control [3]. Essential oils as herbicides could be leaf-sprayed [4][5][6] or soil-applied [7,8]. However, the most frequently analysed effect of the use of essential oils against weeds is their influence on seed germination and the growth of seedlings [9,10].…”