STUDY ON THE MACRONUTRIENT CONTENT OF APPLE LEAVES IN AN ORGANIC APPLE ORCHARD

Macronutrient contents of soil and apple leaves were investigated in an organic apple orchard in Eastern Hungary in 2002-2004. Soil samples were taken from 0-20 cm depth in April and October. The macronutrient content of leaves was measured on cvs. Jonagold, Mutsu, Idared, Red Elstar, Egri Piros, Reka, and Remo at six assessment dates (from April to September). The macronutrient contents of N, P, K, S, Ca and Mg were measured in both soil and leaf samples, then macronutrient ratios were calculated from the obtained results. The results showed that younger leaves contained more N and P than older ones. K and Ca contents of leaves decreased until July, then increased slightly, and decreased again. A continuous decrease of the S content of leaves was observed until August. The Mg content of leaves increased until June, then decreased in July and then increased again. Macronutrient values were dependent on cultivar. Calculated macronutrient ratios showed that the nutrient supply of soil was not optimal in the orchard

Characterization of Three-Dimensional Spatial Aggregation and Association Patterns of Brown Rot Symptoms within Intensively Mapped Sour Cherry Trees

Characterization of spatial patterns of plant disease can provide insights into important epidemiological processes such as sources of inoculum, mechanisms of dissemination, and reproductive strategies of the pathogen population. While two-dimensional patterns of disease (among plants within fields) have been studied extensively, there is limited information on three-dimensional patterns within individual plant canopies. Reported here are the detailed mapping of different symptom types of brown rot (caused by Monilinia laxa) in individual sour cherry tree (Prunus cerasus) canopies, and the application of spatial statistics to the resulting data points to de-termine patterns of symptom aggregation and association. Methods – A magnetic digitizer was uti-lized to create detailed three-dimensional maps of three symptom types (blossom blight, shoot blight, and twig canker) in eight sour cherry tree canopies during the green fruit stage of develop-ment. The resulting point patterns were analyzed for aggregation (within a given symptom type) and pairwise association (between symptom types) using a three-dimensional extension of nearest-neighbor analysis. Key Results – Symptoms of M. laxa infection were generally aggregated within the canopy volume, but there was no consistent pattern for one symptom type to be more or less aggre-gated than the other. Analysis of spatial association among symptom types indicated that previous year’s twig cankers may play an important role in influencing the spatial pattern of current year’s symptoms. This observation provides quantitative support for the epidemiological role of twig can-kers as sources of primary inoculum within the tree. Conclusions – Presented here is a new approach to quantify spatial patterns of plant disease in complex fruit tree canopies using point pattern anal-ysis. This work provides a framework for quantitative analysis of three-dimensional spatial patterns within the finite tree canopy, applicable to many fields of research

Temporal Dynamics of Incidence of Shot Hole Disease Affected by Training Systems and Cultivar Susceptibilities in an Integrated Plum Orchard

Shot hole disease (SHD) can cause severe epidemics in plum orchards, depending on cultivar susceptibility and training system; however, the combined effect on the progress of temporal disease and on the possible reduction in SHD in the disease management was not investigated. The aim of this 3-year study was (i) to monitor and analyze the temporal dynamics of SHD progress under four training systems (4 × 1.5, 4 × 2, 5 × 2.5 and 6 × 3 m) and on four plum cultivars (‘Čačanska lepotica’, ‘Bluefre’, ‘Stanley’ and ‘President’) in an integrated plum orchard; (ii) to identify those time periods when training system and cultivar combinations can reduce the disease development. Both SHD incidences and the area under the disease progress curves (AUDPC) were significantly affected by the training system, cultivar and year. Plum cultivars with high or mid–high susceptibility to SHD showed continuous SHD development from May to November, while cultivars with low susceptibility to SHD showed no symptoms until mid-summer and then progressed slowly until November. High (4 × 1.5 m) vs. low (6 × 3 m) density training systems reduced SHD incidence and AUDPC consistently for three cultivars (‘Čačanska lepotica’, ‘Stanley’ and ‘President’) in September, October and November, compared to the high-density training system. Only cv. ‘Bluefre’ showed no effect either on disease incidence or AUDPC, due to very high disease incidences in all training systems from September to November. In conclusions, combinations of training system and cultivar can significantly reduce SHD incidence, which may be successfully used as a part of the integrated pest management approach during the establishment new plantations

On-farm and on-station evaluations of three orchard management approaches against apple scab and apple powdery mildew

In a three-year study (from 2012 to 2014), the efficacy of three apple management approaches (conventional, standard and advanced Integrated Pest Management - CON, IPM1 and IPM2, respectively) was aimed to investigate against apple scab and apple powdery mildew in on-station (small research scale) and on-farm (real large farm scale using existing farm equipment) experiments in order to promote practical adoption of environmentally sustainable management methods. CON used generally applied conventional pest management practices (disease/pest forecasting coupled with conventional pesticide use). IPM1 used a generally applied integrated pest management practices in most European countries (disease/pest forecasting, yellow/green-list fungicide use coupled with pruning against both diseases, yellow/green-list insecticide use coupled with mating disruption against insects). IPM2 used an advanced integration of known non-chemical practices, accepting most principles of organic farming guidelines (disease/pest forecasting, delayed fungicide applications with green-list fungicide use, pruning against both diseases coupled with orchard sanitation, biological control and mating disruption against insects). Scab and powdery mildew incidences were not significantly different between IPM1 and CON while disease incidences were significantly higher in IPM2 compared to either CON or IPM1 (P = 0.05). Overall yield was not significantly different among the three management approaches. However, the amounts of first class fruit were the highest in CON and IPM1 which were significantly higher (P = 0.05) than that of in IPM2. The amount of second class fruit was the highest in IPM2, indicating a lower fruit quality in IPM2 than in CON or IPM1. In addition, overall disease incidences and fruit quality were generally lower in the on-farm than in the on-station conditions. Our research suggested that elements of IPM1 can be easily adopted by apple growers. Despite the advanced integration of non-chemical control practices in IPM2, its future adoption will depend on the control efficacy and the economic sustainability of non-chemical control practices

Metschnikowia Species Share a Pool of Diverse rRNA Genes Differing in Regions That Determine Hairpin-Loop Structures and Evolve by Reticulation.

Modern taxonomy of yeasts is mainly based on phylogenetic analysis of conserved DNA and protein sequences. By far the most frequently used sequences are those of the repeats of the chromosomal rDNA array. It is generally accepted that the rDNA repeats of a genome have identical sequences due to the phenomenon of sequence homogenisation and can thus be used for identification and barcoding of species. Here we show that the rDNA arrays of the type strains of Metschnikowia andauensis and M. fructicola are not homogenised. Both have arrays consisting of diverse repeats that differ from each other in the D1/D2 domains by up to 18 and 25 substitutions. The variable sites are concentrated in two regions that correspond to back-folding stretches of hairpin loops in the predicted secondary structure of the RNA molecules. The substitutions do not alter significantly the overall hairpin-loop structure due to wobble base pairing at sites of C-T transitions and compensatory mutations in the complementary strand of the hairpin stem. The phylogenetic and network analyses of the cloned sequences revealed that the repeats had not evolved in a vertical tree-like way but reticulation might have shaped the rDNA arrays of both strains. The neighbour-net analysis of all cloned sequences of the type strains and the database sequences of different strains further showed that these species share a continuous pool of diverse repeats that appear to evolve by reticulate evolution

Yield and cost–benefit analyses for apple scab sanitation practices in integrated and organic apple management systems

Societal Impact statement Reduced fungicide use lowers environmental pollution and enables safer food production. The usage of fungicides in apple orchards can be reduced through the application of sanitation practices which decrease the inoculum sources of apple scab disease on fallen leaves. This study found two non‐chemical sanitation practices, namely the collection of fallen leaves (CFL) and CFL combined with straw mulch in tree rows, were beneficial. These two practices are not only biologically and environmentally valuable, as they reduce disease levels and can replace chemical fungicides, but they are also economically efficient options for integrated and organic orchards compared to non‐sanitized ones. Summary Severe fungicide use can be reduced by applications of sanitation practices in order to reduce scab incidence, yield and fruit quality losses in apple orchards. In a 5‐year study, we aimed to investigate the effect of sanitation practices on biological and cost–benefit parameters in two sustainable apple management systems, and to find significant correlations among the parameters. We investigated the effect of five sanitation treatments (lime sulphur, leaf collection, mulching, lime sulphur + leaf collection, leaf collection + mulching) on four biological (scab incidence, fruit parameters: total yield, yield class I and II) and seven cost–benefit (three cost types, three annual revenue types, income surplus/deficit) parameters in integrated and organic apple orchards. Correlation, linear regression and principal component analyses (PCA) were performed to find correlations among biological and cost–benefit parameters. Results showed that fruit scab incidence was 3.4–8.1 times higher, while total yield was 1.4–1.8 times lower in the organic management system than in the integrated one. The treatment of leaf collection and/or leaf collection + mulching showed higher total cost (180.3 and 675.2 EUR ha−1) but lower scab incidence (5.3 and 27.3%; 4.8 and 26.7%, integrated and organic, respectively) and higher yield with greater total revenues (10,235 and 10,329 EUR ha−1; 8,136 and 8,230 EUR ha−1, integrated and organic, respectively) and income surpluses (851 and 451 EUR ha−1; 897 and 496 EUR ha−1, integrated and organic, respectively) compared to non‐sanitized control treatments in most cases. Other sanitation treatments provided fewer biological and/or no financial benefits. Results from correlation and linear regression analyses indicated strong relationships among the factors of total yield vs surplus, class I vs surplus, and fruit scab vs class II) in both management systems. Further relationships were detected among almost all parameters in the PCA. Overall, our study demonstrated that two non‐chemical sanitation treatments could not only reduce scab incidence and increase fruit yield, but could show positive cost–benefit outcomes in both management systems

Network analysis of the cloned D1/D2 sequences.

<p>(A) Rooted rectangular phylogenetic network. Dotted lines represent network edges. (B) Neighbor-net splits graph. The scale bar represents the split support for the edges. Clusters described in the text are denoted by Roman numerals.</p

Tree species composition mapping with dimension reduction and post-classification using very high-resolution hyperspectral imaging

Abstract Tree species’ composition of forests is essential in forest management and nature conservation. We aimed to identify the tree species structure of a floodplain forest area using a hyperspectral image. We proposed an efficient novel strategy including the testing of three dimension reduction (DR) methods: Principal Component Analysis, Minimum Noise Fraction (MNF) and Indipendent Component Analysis with five machine learning (ML) algorithms (Maximum Likelihood Classifier, Support Vector Classification, Support Vector Machine, Random Forest and Artificial Neural Network) to find the most accurate outcome; altogether 300 models were calculated. Post-classification was applied by combining the multiresolution segmentation and filtering. MNF was the most efficient DR technique, and at least 7 components were needed to gain an overall accuracy (OA) of > 75%. Forty-five models had > 80% OAs; MNF was 43, and the Maximum Likelihood was 19 times among these models. Best classification belonged to MNF with 10 components and Maximum Likelihood classifier with the OA of 83.3%. Post-classification increased the OA to 86.1%. We quantified the differences among the possible DR and ML methods, and found that even > 10% worse model can be found using popular standard procedures related to the best results. Our workflow calls the attention of careful model selection to gain accurate maps