Abstract The ectoparasitic mite Varroa destructor is the most significant parasite of the Western honey bee ( Apis mellifera ) and a major driver of colony losses worldwide. Although extensive research has focused on behavioral and physiological mechanisms of host resistance, comparatively little attention has been paid to potential phenotypic responses of the parasite itself. Here we investigated body size variation in Varroa destructor associated with varroa-resistant and non-resistant honey bee colonies across four European countries. We quantified the dorsal shield area of adult female mites from multiple colonies differing in the honey bee colonies resistance status, using standardized digital image analysis. Across geographically distant non-resistant populations, mite body size was remarkably consistent, with a median dorsal shield area of 1.47 mm 2 . In contrast, mites originating from varroa-resistant colonies were consistently smaller, with a median dorsal shield area of 1.37 mm 2 , representing an approximately 6.8% reduction in body size. This pattern was reproducible across different geographical areas, honey bee genetic backgrounds and beekeeping practices. The striking stability of mite body size in non-resistant populations contrasted with the consistent reduction observed in mites associated with resistant hosts, suggesting a host associated shift in parasite phenotype. Because body size in arthropods integrates developmental conditions, nutritional availability and resource allocation, the observed pattern may reflect altered developmental environments and selective pressures imposed by resistant hosts. Our results show a consistent morphological shift in this globally important parasite associated with resistant hosts and suggest that dorsal shield size in Varroa could serve as a new selection marker for varroa-resistant honey bee colonies.

A novel actinomycete, designated as BCCO 10_0861 T , was isolated from overburden Miocene clay sediments undergoing primary succession in Northwest Czechia and characterized by the polyphasic approach. According to 16S rRNA gene sequence similarity, the strain was closely related to Streptomyces turgidiscabies (99.00%), Streptomyces reticuliscabies DSM 41804 T (98.93%), Streptomyces lacrimifluminis DSM 111125 T (98.15%), and Streptomyces geranii JCM 32177 T (98.08%). Morphological and chemotaxonomic characteristics supported the assignment to the genus Streptomyces . Diagnostic diamino acid in the cell-wall peptidoglycan was meso -diaminopimelic acid and the dominant menaquinone was MK-9(H 6 ). The major cellular fatty acids (> 10%) were anteiso -C 15:0 , iso-C 16:0 , C 16:1 ω7c, and C 16:0 . The polar lipid profile comprised of aminophospholipids, diphosphatidylglycerol, glycophospholipids, phosphatidylethanolamine, phosphatidylinositol, and three unidentified phospholipids. The whole cell sugars were galactose, glucose, mannose, ribose, and traces of rhamnose. The genome size of the strain BCCO 10_0861 T was 10.6 Mb with G + C content of 70.1 mol%. Bioinformatic analysis suggested several biosynthetic gene clusters (BGCs) with medium-to-high similarity confidence to already known BGCs, having ethylenediaminesuccinic acid hydroxyarginine (EDHA), humidimycin, inthomycin B, and triascin C unique to BCCO 10_0861 T , however, plenty of identified BGCs with low similarity suggests its biosynthetic potential for novel secondary metabolites. In addition, no mobile genetic elements have been identified in the genome of BCCO 10_0861 T , while the others contained different numbers of insertion sequences. Similarly, predicted antimicrobial resistant genes and plant-growth promoting trait (PGPT) genes differed between genomes, when the one of BCCO 10_0861 T showed the highest number of unique PGPT genes. In addition, no association with potato pathogenicity was predicted in the genome of BCCO 10_0861 T . The digital DNA-DNA hybridization, average nucleotide identity values and phenotype distinguish strain BCCO 10_861 T from closely related strains. Based on the polyphasic approach and genomic content, strain represents a novel species of the genus Streptomyces , for which we propose the name Streptomyces chodovensis sp. nov. for BCCO 10_0861 T (= DSM 117345 T ).

The natural phenolic compound p-coumaric acid supports honey bee health by enhancing detoxification, immunity and longevity. It also possesses antioxidant, anti-inflammatory and anticancer properties relevant to human health. While commonly detected in honey and pollen, it is absent from nectar and sucrose-based supplements typically used in beekeeping. Concerns have been raised whether supplemental saccharide feeding deprives bees of this essential phytochemical. In this study, we quantified p-coumaric acid in various bee-derived products and in supplementary sucrose syrup before and after feeding to bees, using HPLC-HRMS analysis. Although fresh sucrose syrup contained negligible amounts of p-coumaric acid, syrup stored in capped combs exhibited levels comparable to or higher than those in honey. We identified propolis in combs as the primary source of p-coumaric acid, diffusing into both honey and sucrose syrup during storage. Our findings demonstrate that supplemental feeding with sucrose syrup does not diminish the bees’ access to this key phytochemical and underscore the importance of a propolis-rich environment in bee health management.

Deformed wing virus (DWV) transmitted by the parasitic mite Varroa destructor is one of the most significant factors contributing to massive losses of managed colonies of western honey bee (Apis mellifera) subspecies of European origin reported worldwide in recent decades. Despite this fact, no antiviral treatment against honey bee viruses is currently available for practical applications and the level of viral infection can only be controlled indirectly by reducing the number of Varroa mites in honey bee colonies. In this study, we investigated the antiviral potential of the gypsy mushroom (Cortinarius caperatus) to reduce DWV infection in honey bees. Our results indicate that the alcohol extract of C. caperatus prevented the development of DWV infection in cage experiments as well as after direct application to honey bee colonies in a field experiment. The applied doses did not shorten the lifespan of honey bees. The reduced levels of DWV in C. caperatus-treated honey bees in cage experiments were accompanied by significant changes in the gene expression of Tep7, Bap1, and Vago. The C. caperatus treatment was not effective against the trypanosomatid Lotmaria passim. No residues of C.caperatus were found in honey harvested in the spring from colonies supplemented with the mushroom extract for their winter feeding. These findings suggest that C. caperatus alcohol extract could be a potential natural remedy to treat DWV infection in honey bees.

Streptomyces are of great interest in the pharmaceutical industry as they produce a plethora of secondary metabolites that act as antibacterial and antifungal agents. They may thrive on their own in the soil, or associate with other organisms, such as plants or invertebrates. Some soil-derived strains exhibit hemolytic properties when cultivated on blood agar, raising the question of whether hemolysis could be a virulence factor of the bacteria. In this work we examined hemolytic compound production in 23 β-hemolytic Streptomyces isolates; of these 12 were soil-derived, 10 were arthropod-associated, and 1 was plant-associated. An additional human-associated S. sp. TR1341 served as a control. Mass spectrometry analysis suggested synthesis of polyene molecules responsible for the hemolysis: candicidins, filipins, strevertene A, tetrafungin, and tetrin A, as well as four novel polyene compounds (denoted here as polyene A, B, C, and D) in individual liquid cultures or paired co-cultures. The non-polyene antifungal compounds actiphenol and surugamide A were also identified. The findings indicate that the ability of Streptomyces to produce cytolytic compounds (here manifested by hemolysis on blood agar) is an intrinsic feature of the bacteria in the soil environment and could even serve as a virulence factor when colonizing available host organisms. Additionally, a literature review of polyenes and non-polyene hemolytic metabolites produced by Streptomyces is presented.

Purpose Common scab of potatoes (CS) is influenced by plant-microbe-soil interactions, which are locally specific. The study aims to identify any common trends in such interactions across a landscape differentiated by soil pH and CS severity. Methods The 33 sites and 17 cultivars were characterized using soil and periderm nutrient contents and microbial communities. Quantitative PCR and Illumina amplicon sequencing were used to assess abundance of bacteria, actinobacteria and pathogens, and community composition. Results Comparisons between bulk and tuberosphere soil compartments as well as potato cultivars divided to three categories of CS susceptibility revealed that nitrogen was elevated in tuberosphere soil and N, Mg and Fe were lowered in periderm of resistant cultivars. The susceptible cultivar Agria grown at 7 sites had higher Ca content in tuberosphere soil, while the resistant cultivar Adela grown at 10 sites had higher S, P and Mg contents in its tuberosphere soil and P and Fe in periderm. That suggests further interactions between plants and bacterial community involving nutrient uptake. Diversity of bacteria was positively correlated with CS severity suggesting interactions between the Streptomyces pathogen populations and the local soil community. Conclusions Overall, pathogen abundance assessed by quantifying the thaxtomin biosynthetic txtB genes were randomly dispersed among the sites without connections to CS severity or soil pH. Thus, the significant differences between bacterial communities of bulk and tuberosphere soils together with cultivar CS susceptibility showed that the susceptible cultivars select bacterial community relatively similar to the bulk soil, while the resistant cultivars promote more distinct communities.

Worker honey bees are subject to biochemical and physiological changes throughout the year. This study aimed to provide the reasons behind these fluctuations. The markers analysed included lipid, carbohydrate, and protein levels in the haemolymph; the activity of digestive enzymes in the midgut; the levels of adipokinetic hormone (AKH) in the bee central nervous system; the levels of vitellogenins in the bee venom and haemolymph; and the levels of melittin in the venom. The levels of all the main nutrients in the haemolymph peaked mostly within the period of maximal bee activity, whereas the activity of digestive enzymes mostly showed a two-peak course. Furthermore, the levels of AKHs fluctuated throughout the year, with modest but significant variations. These data suggest that the role of AKHs in bee energy metabolism is somewhat limited, and that bees rely more on available food and less on body deposits. Interestingly, the non-metabolic characteristics also fluctuated over the year. The vitellogenin peak reached its maximum in the haemolymph in winter, which is probably associated with the immunoprotection of long-lived winter bees. The analysis of bee venom showed the maximal levels of vitellogenin in autumn; however, it is not entirely clear why this is the case. Finally, melittin levels showed strong fluctuations, suggesting that seasonal control was unlikely.

Streptomycetes, typical soil dwellers, can be detected as common colonizers of human bodies, especially the skin, the respiratory tract, the guts and the genital tract using molecular techniques. However, their clinical manifestations and isolations are rare. Recently they were discussed as possible "coaches" of the human immune system in connection with certain immune disorders and cancer. This work aimed for the characterization and evaluation of genetic adaptations of a human-associated strain Streptomyces sp. TR1341. The strain was isolated from sputum of a senior male patient with a history of lung and kidney TB, recurrent respiratory infections and COPD. It manifested remarkably broad biological activities (antibacterial, antifungal, beta-hemolytic, etc.). We found that, by producing specific secondary metabolites, it is able to modulate host immune responses and the niche itself, which increase its chances for long-term survival in the human tissue. The work shows possible adaptations or predispositions of formerly soil microorganism to survive in human tissue successfully. The strain produces two structural groups of cytotoxic compounds: 28-carbon cytolytic polyenes of the filipin type and actinomycin X2. Additionally, we summarize and present data about streptomycete-related human infections known so far.

Guano is a typical deposit found in caves derived from the excretions of bats and in minor cases of birds. These organic deposits decompose and form a series of acid fluids and gases that can interact with the minerals, sediments, and rocks present in the cave. Over sixty phosphates are known and described from caves, but guano decay also often leads to the formation of nitrates and sulfates. In this study twenty-two European caves were investigated for their guano-related secondary minerals. Using various analytical techniques, seventeen phosphates, along with one sulfate (gypsum), were recognized as secondary products of guano decay. Among those minerals, some are very rare and result from the interaction of guano leachates with clays, fluvial deposits, or pyrite. Some of these minerals are even found only in the studied caves (spheniscidite, robertsite). The most common minerals belong to the apatite group. The common mineral association present in fresh decaying guano is brushiteardealite-gypsum, minerals that usually are not present in older deposits because of their higher solubility. Most minerals are in hydrated form because of the wet cave environment; however, some specific dry conditions may favor the presence of dehydrated minerals, such as berlinite, formed during guano combustion. Investigation on the acidity of guano piles shows pH values as low as 3.5 with an increase of acidity with age and depth. Finally, cave guano deposits should be better studied in the future because of their role in paleoenvironmental and paleoclimatic reconstructions and because it is important to better understand the origin of guano-related minerals, especially the phosphates and sulfates. Among all of the caves studied, Corona 'e sa Craba (Italy) and Domica-Baradla Cave (Slovakia-Hungary) are considered to be outstanding sites with respect to their phosphate mineralogy.

We tested the effect of Chlorella sorokiniana, a green, unicellular, freshwater alga, provided as a food supplement on several biological characteristics of the honey bee Apis mellifera. Chlorella was applied as (1) a moisturized powder, (2) a sugar-water solution, or (3) mixed with honey-sugar candy. All three applications were well accepted by the bees. We observed a positive effect of Chlorella on colony development, and also on basic aspects of metabolism, such as increased fat deposition and vitellogenin transcript levels, and a decrease in TOR and InR2 transcript levels. The effect of Chlorella on other characteristics was lower (protein levels) or even null (total fat body mass, level of adipokinetic hormone). Application of Chlorella modulated the hypopharyngeal gland size, and the activity of basic digestive enzymes in the bee midgut. Our observations suggest that the nutritional composition of Chlorella might be an appropriate dietary supplement for honey bees.

Control of common scab disease can be reached by resistant cultivars or suppressive soils. Both mechanisms are likely to translate into particular potato microbiome profiles, but the relative importance of each is not known. Here, microbiomes of bulk and tuberosphere soil and of potato periderm were studied in one resistant and one susceptible cultivar grown in a conducive and a suppressive field. Disease severity was suppressed similarly by both means yet, the copy numbers of txtB gene (coding for a pathogenicity determinant) were similar in both soils but higher in periderms of the susceptible cultivar from conducive soil. Illumina sequencing of 16S rRNA genes for bacteria (completed by 16S rRNA microarray approach) and archaea, and of 18S rRNA genes for micro-eukarytes showed that in bacteria, the more important was the effect of cultivar and diversity decreased from resistant cultivar to bulk soil to susceptible cultivar. The major changes occurred in proportions of Actinobacteria, Chloroflexi, and Proteobacteria. In archaea and micro-eukaryotes, differences were primarily due to the suppressive and conducive soil. The effect of soil suppressiveness × cultivar resistance depended on the microbial community considered, but differed also with respect to soil and plant nutrient contents particularly in N, S and Fe.

This study examined the expression and role of vitellogenin (Vg) in the body of the firebug Pyrrhocoris apterus (Heteroptera, Insecta) during infection elicited by two entomopathogenic organisms, the nematode Steinernema carpocapsae and the fungus Isaria fumosorosea Infection by S. carpocapsae significantly upregulated Vg mRNA expression in the male body. The corresponding increase in Vg protein expression was also confirmed by electrophoretic and immunoblotting analyses. Remarkably, in females, the opposite tendency was noted. Nematodal infection significantly reduced both Vg mRNA and Vg protein expression levels in fat body and hemolymph, respectively. We speculate that infection of reproductive females reduces Vg expression to a level that is still sufficient for defense, but is insufficient for reproduction. This circumstance reduces energy expenditure and helps the individual to cope with the infection. Importantly, purified Vg significantly inhibited growth of Xenorhabdus spp., an entomotoxic bacteria isolated from S. carpocapsae. However, the effect of Vg against I. fumosorosea was not so obvious. The fungus significantly stimulated Vg gene expression in males; however, a similar increase was not recapitulated at the protein level. Nevertheless, in females, both mRNA and protein Vg levels were significantly reduced after the fungal infection. The obtained data demonstrate that Vg is probably an important defense protein, possibly with a specific activity. This considerably expands the known spectrum of Vg functions, as its primary role was thought to be limited to regulating egg development in the female body.

Observations of earthworm colonization on sites where they were absent previously, such as on post-mining heaps, indicate that they may substantially alter soil conditions as well as soil microbial communities. However, long-term effects of earthworms on microbial activity of soil ecosystems remains poorly understood. To improve this situation, we set up microcosm experiments with clay only, with clay and litter, and with clay, litter and earthworms. Microcosms were sampled after 3, 60, 180 and 395 days of cultivation and divided into three subsamples: clay, litter, and drilosphere (earthworm tunnels and associates casts), when present. Microbial respiration, microbial biomass carbon, species composition, metabolic activity using BIOLOG, PLFA concentration, isoprenoid quinones content and DGGE fingerprints were analysed in all microcosms and at all subsamples. Microbial biomass carbon and basal soil respiration were significantly affected by type of microcosms and time of sampling. Microbial biomass in drilosphere was significantly higher than in clay and litter. The CFU (colony forming units) were significantly affected by presence of earthworms having significantly higher CFU in drilosphere than in all other subsamples. Analysis of PLFA indicated highest relative biomass of fungi and bacteria in clay from microcosms with earthworms. The DGGE analysis showed various compositions of microbial communities among subsamples from various treatments taken at different time. Finally, our results revealed significant effect of earthworms on activity and biomass of soil microbial community under long-term laboratory incubation.

Soil formation in post-mining sites is crucial for restoring ecosystem function, and soil formation depend on the accumulation of soil organic matter and the development of an active microbial community. In this study, we used substrate-induced respiration (SIR) and Biolog plates to characterize microbial catabolic profiles in a chronosequence of soil samples from 15 unreclaimed post-mining sites in Sokolov, Czech Republic. The sites had been undergoing spontaneous succession for 3 to 45 years. Biolog ECO plates included 31 substrates. Of substrates used for SIR (glucose, chitin, cellulose, Tween 80, phenylethylamine, N-acetyl-D-glucosamine, L-asparagine, D-mannitol, D-galacturonic acid, α-cyclodextrin, and 4-hydroxy benzoic acid), eight were also used for the Biolog plates. Soil respiration, total bacteria number, and culturable bacteria number were also measured. The total and culturable number of bacteria increased with site age (p < 0.01 and p < 0.05, respectively). The percentage of culturable bacteria decreased with site age (p < 0.01). Biolog analysis indicated that average well-color development (AWCD), evenness, and richness increased with site age. SIR data indicated that only average activities tended to increase with site age (p = 0.06). According to redundancy analysis (RDA), the eight substrates, which were commonly used in both methods (SIR and BIOLOG) explained 74.4% of the variation of data from all Biolog substrates. Among the eight substrates common to both methods, only data for N-acetyl-D-glucosamine were positively correlated (p < 0.01) between Biolog and SIR. Both methods revealed microbial catabolic profile changed along the chronosequence. PCA indicated that site age, soil carbon, and pH were the most important drivers of microbial catabolic profiles.

Factors shaping community structure of soil microbiota have been intensively studied; however, the pattern in community composition and structure of soil microbiota at large geographical scales and factors regulating its metabolic activity remains poorly understood. Here, we used a field transplantation experiments to investigate the effects of substrate and climatic conditions on basal soil respiration, microbial biomass C and diversity of soil microbiota by comparing local and transplanted soils along a latitudinal gradient. Soil samples collected in April 2008 at donor site (Sokolov, Czech Republic) in Central Europe were gamma-ray sterilized and transplanted to receptor sites in Europe and the USA in May and early June 2008. Soil samples were taken in June 2009 after one year of exposure and immediately prepared for laboratory analysis. Basal soil respiration in local soils increased from 22 to 42 mg CO2.C kg(-1) h(-1) with latitude while basal soil respiration in transplanted soils decreased with latitude from 32 to 19 mg CO2.C kg(-1) h(-1). The microbial biomass C in both transplanted and local soils decreased with latitude. Content of fungal and bacterial phospholipid fatty acids increased nearly twice with latitude in local soils. Shannon diversity index of fungal community decreased from 2.5 to 1.2 along the latitudinal gradient in transplanted soils while local soils increased from 0.9 to 2.4 with latitude. Based on our results, microbial activity is driven mainly by changes of the soil substrate along latitudinal and climatic gradients while microbial biomass is driven more by global climatic factors itself. The diversity of soil microbial communities is mostly affected by latitudinal and climatic factors while community structure is mostly shaped by substrate quality.

Connections between the structure of bacterial communities in suppressive soils and potato resistance to common scab (CS) are not well understood. In this study, one resistant and one susceptible cultivar were grown in a conducive and suppressive field to assess cultivar resistance x soil suppressiveness interactions. The resistant cultivar had a higher Mg content in periderm compare to susceptible cultivar, while suppressive soil had lower pH (5.3 vs 5.9), N, C, P, Ca contents but higher Fe and S compared with the conducive soil. Bacteria and actinobacteria numbers were higher in the conducive soil. Copy numbers of txtB gene (coding for a pathogenicity determinant) were similar in both soils but were higher in the conducive soil (for periderm samples) and in the susceptible cultivar (for conducive soil samples). Taxonomic microarray analysis and Illumina sequencing of 16S rRNA genes amplicon showed that bacterial community differed between resistant vs susceptible cultivar and to a lesser extend between suppressive vs conducive soil. Bacteria participating in soil suppression belonged to Pseudomonadaceae, Bradyrhizobiaceae, Acetobacteraceae and Paenibacillaceae, while resistant cultivars selected a bacterial community resembling that of the suppressive soil, which was enriched in Nitrospirae and Acidobacteria. Thus, the analysis of soil suppressiveness x cultivar resistance interactions enabled to gain new insight to CS control in the field.

Predicting the composition and function of microbial communities at a bio-geographical scale, across ecosystems, is challenging. We compared six abandoned fields to six meadows to see whether soil microbial community structure and activity are more similar within the ecosystem type than between the types. We implemented bacteria and fungi phylogenetic markers profiling, phospholipids analysis, fluorescence counts of total bacteria and algae and microscopy of arbuscular mycorrhizal fungi (AMF). The functional performance of microbial communities was assessed using enzymes activity measurements as well as culturing and incubation experiments. The studied fallows and meadows had similar biomass and general structure of soil microbial communities. However, the AMF root colonization frequency was higher in the meadows than in the fallows. The AMF colonization was promoted in meadows characterised by lower availability of NO3−, P and K as well as higher soil pH, which additionally hampered plant acquisition of P at the P-limited ecosystem. Fallow and meadow microbial communities showed characteristic functional traits. Meadow soils exhibited higher basal respiration rate, while cellulose decomposition and nitrogen mineralization were faster in fallows. Even when no major differences in community structure could have been detected soil microbial communities adapted to local and/or instantaneous environmental conditions and formed functionally-specific ecotypes. This work points out the relevance of preserving meadows as reservoirs of plant diversity, which cope excellent in nutrient depleted conditions and in mountain regions thanks to microbial components of ecosystem.

We compared methane (CH4) and carbon dioxide (CO2) fluxes in samples collected from the aboveground parts of wood ant nests and in the organic and mineral layer of the surrounding forest floor. Gas fluxes were measured during a laboratory incubation, and microbial properties (abundance of fungi, bacteria and methanotrophic bacteria) and nutrient contents (total and available carbon and nitrogen) were also determined. Both CO2 and CH4 were produced from ant nest samples, indicating that the aboveground parts of wood ant nests act as sources of both gases; in comparison, the forest floor produced about four times less CO2 and consumed rather than produced CH4 Fluxes of CH4 and CO2 were positively correlated with contents of available carbon and nitrogen. The methanotrophic community was represented by type II methanotrophic bacteria, but their abundance did not explain CH4 flux. Fungal abundance was greater in ant nest samples than in forest floor samples, but bacterial abundance was similar in both kinds of samples, suggesting that the organic materials in the nests may have been too recalcitrant for bacteria to decompose. The results indicate that the aboveground parts of wood ant nests are hot spots of CO2 and CH4 production in the forest floor.

Common scab of potatoes is a disease, which is difficult to manage due to complex interactions of the pathogenic bacteria (Streptomyces spp.) with soil, microbial community and potato plants. In Bohemian-Moravian Highlands in the Czech Republic two sites (Vyklantice and Zdirec) were selected for a study of common scab disease suppressivity. At both sites, a field with low disease severity occurs next to one with high severity and the situation was regularly observed over four decades although all four fields undergo a crop rotation. In the four fields, quantities of bacteria, actinobacteria and the gene txtB from the biosynthetic gene cluster of thaxtomin, the main pathogenicity factor of common scab, were analyzed by real-time PCR. Microbial community structure was compared by terminal fragment length polymorphism analysis. Soil and potato periderm were characterized by contents of carbon, nitrogen, phosporus, sulphur, calcium, magnesium, and iron. Quality of organic matter was assessed by high performance liquid chromatography of soil extracts. The study demonstrated that the suppressive character of the fields is locally specific. At Zdirec, the suppressivity was associated with low txtB gene copies in bulk soil, while at Vyklantice site it was associated with low txtB gene copies in the tuberosphere. The differences were discussed with respect to the effect of abiotic conditions at Zdirec and interaction between potato plant and soil microbial community at Vyklantice. Soil pH, Ca soil content or cation concentrations, although different were not in the range to predict the disease severity. Low severity of common scab was associated with low content of soil C, N, C/N, Ca and Fe suggesting that oligotrophic conditions may be favorable to common scab suppression.

Common scab (CS) severity was assessed in relationship to mineral contents of potato periderm in 18 cultivars varying in maturity period and CS susceptibility. Two field experiments, one repeated in 3 years, were conducted. The effect of site, cultivar and growing period on the disease severity was always significant but not that of year to year variability. Zn, Mn and Fe periderm contents were related to site, while Ca content to cultivar effects. In both experiments, the CS severity was positively correlated to calcium and negatively to phosphorus periderm content, while correlations of CS severity to other nutrients were dependent on site or year. Since soil pH, Ca and P soil contents were not different between sites, relatively small differences in other soil chemical characteristics combined with specific cultivar nutrient requirements seemed to determine the CS severity.