Temperature strongly influences the growth of maize, particularly in the early growth stages. The exogenous application of some amino acids has been proven to have a positive effect on plant growth and development under stressful conditions. The objective of the study was to evaluate the response of maize that was grown under an optimal and stress (fluctuating) temperature to L-Arginine (L-Arg) and Glycine (Gly) application. In the study, it was assumed that the exogenously applied amino acids would alleviate the adverse effects of temperature stress on the maize height, as well as on the biomass of shoots and roots. Ten concentrations of each amino acid from 0.006 mM to 9.0 mM were tested under constant temperature conditions 20–22 °C/23–25 °C (night/day) an fluctuating stress of rising and dropping temperatures between 12–15 °C (night) and 30–38 °C (day). The amino acids were applied to the crop at growth stages V3–V4. In plants that were obtained from seeds pre-treated with L-Arg and Gly, the amino acids increased both the length of radicles and the number of lateral roots. A large discrepancy between the effects of the two amino acids was observed after foliar application. Under optimal thermal conditions, L-Arg increased the mass of shoots and roots by 55–59%. Under stress conditions, root mass was increased even by 100% when compared to the control plants. The best results were recorded at concentrations of 6 mM and 3 mM. Plants that were treated with Gly concentrations generally reached the height of untreated plants or less. It was shown that Gly applied at concentrations of 0.2 mM to 3 mM has a negative effect on the fresh mass of the crop.

Although the knowledge on agricultural using of biostimulants increases, there is still little information on their interactions with other chemicals i.e. herbicides. The aim of the study was to assess the influence of popular herbicides (MCPA + dicamba, dicamba + triasulfuron, florasulam+2,4-D) used with and without biostimulants based on seaweed extract (Kelpak) and nitrophenols (Asahi) on weed control efficiency, yield and quality of the crop. Field trial was carried out in the years 2014 and 2015 in the Institute of Plant Protection - National Research Institute in Poznan (Poland). The experiment was established on spring wheat cv.‘Torridon’, in 4 replications, using randomized block design. In the experiment two variants of application were tested. In the first variant preparations (herbicide and biostimulant) were applied as tank mixtures at the crop growth stage BBCH 30 and in the second variant in some combinations herbicide application was followed by biostimulant used alone. Weather conditions had a profound impact on tested preparations activity. Addition of biostimulants to herbicide had not affected weed control efficacy but application of herbicide and biostimulant mixture revealed its influence on yield parameters of wheat. Biostimulants influenced yield quality parameters e.g. by enhancing gluten amount in grains.

A two-factor field experiment using sugar beet was conducted in 2016–2018 at Sokołowo in Poland (ϕ 53°5′16.05″ N, λ 19°6′21.07″ E), in a strip-plot arrangement with four replicates. Strip-till (ST) was compared to conventional tillage (CT) using four commercial sugar beet varieties (Alegra, Armesa, Contenta, Julius). In each study year, the experiment was established on lessivé soils developed from heavy loamy sand. The soil was rich in available macronutrients, while its reaction was neutral. The plant density, sugar yield, roots quality, and technological sugar yield were determined. A significant increase was found in root yield (6.6%) and, accordingly, in technological sugar yield (8.2%) in ST treatment relative to CT. Consistently, an increasing trend was observed for the root sugar content (0.21%). For the varieties examined, no preferences were observed in respect of tillage systems applied. The direction of changes in root yield, sugar content, and technological sugar yield remained constant regardless of the variety, tillage system, or the study year. The contents of potassium, sodium, and α-amino-nitrogen responded equally to both the variety and study year; however, the direction of changes in the above parameters was ambiguous and varied among the study years.

Decreasing efficacy of fungicides and the withdrawal of further hazardous active ingredients in pesticides from use have prompted the search for alternative methods of crop protection. Essential oils (EOs) are secondary metabolites of plants and have been proven to show antibacterial, antifungal, and pest-repellent properties. This study was undertaken to determine the activity of grapefruit, rosemary, pine, sage, and thyme EOs against the fungus Cercospora beticola, which is the most dangerous pathogen of sugar beet and the causal agent of Cercospora leaf spot. According to the determined Minimum Inhibitory Concentration (MIC), thyme EO was found the most effective against C. beticola. For most of the fungal isolates tested, the MIC of this EO was 0.313 mL/L. Thyme EO also inhibited the growth of multi-resistant isolates. Based on the results obtained, thyme EO was subjected to further testing in field conditions, where its efficiency in controlling C. beticola was also proven. The results indicate that the use of thyme EO may be a promising method for the protection of sugar beets, although it requires further optimization in the context of its inclusion in sustainable protection programs assuming a reduced number of synthetic fungicide treatments.

During potato desiccation the above-ground parts can be destroyed by mechanical, mechanical-chemical, or chemical methods. In the current study, the mechanical-chemical method was used and instead of chemical compounds natural nonanoic acid (pelargonic acid) was used. Nonanoic acid is a natural active ingredient that can be extracted from vegetable oil (rapeseed oil). It is a short chain fatty acid and a natural product, that fits well with the principles of the Green Revolution, which has introduced restrictions worldwide on the use of chemical plant protection products and promotes natural ones. For comparison carfentrazone-ethyl and glufosinate-ammonium were used. Studies were carried out in Poland during 2012–2014 with the potato variety Ikar, which is known to be among the varieties difficult to desicccate in Poland. The results show that potato leaves were efficiently destroyed by both nonanoic acid and chemicals (carfentrazone-ethyl and glufosinate-ammonium). The level of destruction varied from 94.5% to 99%. The level of stalk drying caused by nonanoic acid was high and it was similar to that of chemical desiccants. None of the studied desiccants significantly affected yield, vascular necrosis or quantity of starch in tubers.

The field research were carried out in 2019–2020, in Picobella sugar beet. The aim of the study was to develop an alternative weed control program without phenmedipham, desmedipham and chloridazone. The tested mixtures containing metamitron, ethofumesate, triflusulfuron-methyl, and lenacil used in various combinations together with the Atpolan BIO 80 EC adjuvant effectively controlled Fat hen (Chenopodium album) up to phase 1 of a pair of true leaves (BBCH 12). Excluding ethofumesate from mixtures of metamitron (700 g/ha) and triflusulfuron-methyl (15 g/ha) reduces the effectiveness of weed control. In the absence of ethofumesate, the effectiveness of the action is improved by increasing the dose of metamitron (1050 g/ha) and adding lenacil (100 g/ha) to the composition of the mixture. The conducted research proved that it is possible to effectively protect beet crops against Fat hen (Ch. album) after the desmedipham withdrawn and possible non-approval of phenmedipham and chloridazone.