Preliminary results of rootstock evaluation for Estonian sweet cherry cultivar ‘Anu’

Mahaleb cherry (Prunus mahaleb L.) is the most widely used rootstock for sweet cherries in Latvia, however it has several disadvantages - strong vigour of grafted trees and an intolerance to heavy, waterlogged soils. The aim of the study was to test the suitability of rootstocks of different origins for winter-hard sweet cherry cultivar in Latvian climate. The trial was established in the spring of 2014 at the Institute of Horticulture (LatHort) to test four clonal rootstocks: ‘PiKu 1’, PHL-A’, ‘GiSelA 5’, ‘VSL-1’, and generative rootstock P. mahaleb (control) grafted with cultivar ‘Anu’ (Estonian breeding). Cherries were planted at 5×3.5 m in a random block design in three replications with three trees per plot. Tree height, annual growth of shoots, the viability of trees after wintering period and the intensity of flowering and production were evaluated in 2016–2019. Sweet cherry cultivar ‘Anu’ had the best overall winter-hardiness in the combinations with rootstocks ‘GiSelA 5’ and P. mahaleb. The highest intensity of flowering and production were observed in trees grafted on ‘GiSelA 5’. Trees on ‘VSL-1’ had the highest decease rate and the lowest winter hardiness

Influence of vermicompost on strawberry plant growth and dehydrogenase activity in soil

Vermicompost is increasingly becoming popular as an organic fertiliser used for different crops. Effects of vermicompost on strawberry plant growth and soil properties were studied in this investigation. The research was performed in LatHort from 2015 to 2017. Strawberry was grown on open field in rows. Two trials were established. In Trial 1, the application of vermicompost with a dose of 50 mL per plant was compared to growing without any fertilization. In Trial 2, several treatments were used: 1) only inorganic mineral fertilization applied; 2) vermicompost applied with a dose of 100 mL per plant in planting holes, later mineral fertilization applied; 3) vermicompost applied with a dose of 100 mL per plant in planting holes, no additional fertilization applied; 4) vermicompost applied two times per season on the ground around plants with dose of 50 mL per plant, no mineral fertilization applied. The plant growth was assessed two times per season by evaluating the amount of leaves and plant height. Soil dehydrogenase activity was evaluated during all growing seasons as indicator of soil microbial activity. The application of vermicompost positively influenced plant growth in comparison to growing without fertilization. In Trial 2, plant growth varied among years. During first two growing seasons better plant growth was observed for plants fertilized by inorganic mineral fertilizers, while later the growth levelled off for all treatments applied. The application of vermicompost had positive influence on the soil dehydrogenase activity in contrary to fertilization by mineral fertilizers

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

Water levels and soil mulches in relation to strawberry diseases an yield in a greenhouse Irrigação e cobertura do solo em relação à sanidade e produtividade do morangueiro sob estufa

The occurrence of diseases and its influence on strawberry yield in a greenhouse as well as its association with water management are still not well known. So, the aim of this work was to evaluate the effect of different water levels and soil mulches on strawberry plant health and yield in a greenhouse. The experiment was carried out at Atibaia, State of São Paulo, Brazil, from April to December 1995. The experimental design was a 2 &times; 3 factorial, in randomized blocks, with five replications, and consisted of two soil mulches and three water levels. The soil mulches consisted of clear or black plastic. Trickle irrigation was applied whenever the soil water potential reached -10, -35 and -70 kPa at a depth of ten centimeters. Cultivar Campinas IAC 2712 was used. Plants grown at a soil water potential of -10 and -35 kPa, with clear plastic mulch provided the best yields. A linear function fitted well considering total yield data and irrigation depths. The equation was y = -233.54 + 1.56x (R² = 0.78). The irrigation level of -70 kPa and the use of black plastic favored a greater incidence of soil-borne diseases late in the harvest season.<br>A influência de doenças na produtividade do morangueiro cultivado em estufa, bem como sua associação com o manejo da irrigação é pouco conhecida. Desta forma, o presente trabalho teve por objetivo avaliar o efeito de diferentes níveis de água e coberturas do solo na sanidade e produtividade do morangueiro, sob ambiente protegido. O experimento foi realizado em Atibaia, estado de São Paulo, Brasil, de abril a dezembro de 1995. O delineamento utilizado foi o fatorial 2 &times; 3, em blocos ao acaso, com cinco repetições, sendo estudados duas coberturas do solo (plástico transparente e preto) e três níveis de água. A irrigação, por gotejamento, foi aplicada quando o potencial de água no solo alcançava -10, -35 e -70 kPa à profundidade de dez centímetros. A cultivar utilizada foi a Campinas IAC 2712. As plantas cultivadas nos potenciais de água de -10 e -35 kPa ou com o plástico transparente apresentaram as melhores produtividades. A equação estimada foi y = -233,54 + 1,56x (R² = 0,78). A irrigação a -70 kPa e o plástico preto favoreceram a maior incidência de patógenos do sistema radicular no período de outubro a dezembro