Environmental risk assessment studies on new plant protection products which have been elaborated from coniferous tree bark

ArticleNowadays there are still various chemical pesticides being applied in the course of ensuring plant protection. Since 2010, we have been working on the development of new, environmentally-friendly plant protection products which will provide an effective tool against pathogenic fungi and bacteria which cause disease in crop plants. The specific aim of this study was to evaluate a risk assessment for new plant protection products that have been elaborated on the basis of coniferous tree bark. Various products were tested which are extracted during the processing of wood bark from pine (Pinus sylvestris L.) and spruce (Picea abies (L.) Karst.). Ethanol extracts were formulated and applied during these experiments. Two formulations, which showed anti-fungal activity in vitro and in field trials on fruit crops (involving strawberries and raspberries) were selected for the risk assessment studies. The impact was studied of formulation treatment on crop plants and soil biological activity, and the accumulation of residues of active substances in crop plants and soil. The application of new formulations did not show any negative effect on the chlorophyll content and the chlorophyll fluorescence of plant leaves. The results showed that pine and spruce bark extract formulations contain active compounds (coumaric acid, quercetin, epicatechin, and ferulic acid) within the range of 5.1–5.9 mg kg-1 and 11.1– 443.9 mg kg-1 respectively. The amount of active substances which were determined in most cases was higher in the spruce bark extract formulation when compared to the pine bark extract formulation. Our results confirmed the presence of active compounds – epicatechin, quercetin, and coumaric acid – in strawberry fruits which remained untreated and in those that were treated with spruce ethanol extract formulation. Untreated raspberry fruits contained all four active substances within the range of 81–5,300 µg kg-1. We observed a significant increase of coumaric acid and quercetin in raspberries after their having been treated with spruce bark extract formulation in a 2% concentration, P < 0.05, and did not find any negative impact for spruce bark extract formulations when used on soil microbial biomass

Influence of the erineum strain of Colomerus vitis (Acari: Eriophyidae) on grape (Vitis vinifera) defense mechanisms

Grape (Vitis vinifera) is commonly affected by the erineum strain of Colomerus vitis (GEM) in Iran and the susceptibility of grape cultivars to GEM is poorly understood. In order to evaluate the impact of GEM on grape and its defense mechanisms against the mite, an exploratory study was carried out on 19 cultivars (18 Iranian and the non-native Muscat Gordo). The differential susceptibility of cultivars to GEM was compared on the basis of the area of leaf damage induced by GEM. The cultivars White Thompson seedless of Bovanat, Atabaki Zarghan, Koladari Ghoochan and Sahebi Uroomie were less susceptible to GEM, whereas Ghalati Dodaj, Rishbaba, Muscat Gordo and Neyshaboori Birjand appeared to be the most affected by the mite. In a no-choice setup, plants of selected cultivars of these two groups were infested by GEM and assayed for 10 biomarkers usually related to plant stress mechanisms against plant feeders: the activity of defense enzymes—peroxidase (POX), polyphenol oxidase (PPO), superoxide dismutase (SOD), phenylalanine ammonia-lyase (PAL), catalase (CAT), the amount of total polyphenolics, total flavonoids, total soluble carbohydrates, hydrogen peroxide (H2O2), and malondialdehyde (MDA) expressing lipid peroxidation. The biomarkers were assessed in grape leaves 7 days before releasing the mites, as well as 7, 14 and 28 days after infestation (DAI). The activity of the enzymes and the amount of the compounds usually increased in percentage after mite infestation. A significant negative correlation was found between the area of leaf damage and PPO, POX, SOD, MDA and H2O2for all sampling dates. The area of leaf damage showed a significant positive correlation with total soluble carbohydrates at 28 DAI, and significant negative correlations with CAT (at 14 and 28 DAI), PAL and total flavonoids (at 7 DAI). No correlation was observed between area of leaf damage and total polyphenolics. The biomarkers PPO, SOD, CAT activity and H2O2provided the best explanation for the response of grape cultivars to GEM infestation