A total of 15 isolates of B. tulipae collected from home grown tulips without chemical protection and two commercial tulip plantations were examined by RAPD fingerprint analysis. The first tulip plantation was protected by bulb treatment and foliage spraying with fungicides in the growing period and the second plantation – only by the application of fungicides in the growing period. In the previous study, a set of isolates obtained from a plantation with an extensive use of fungicides demonstrated a higher pathogenicity level measured by the inhibition of plant growth, the percentage of bulb and root necrosis in flower pot tests on forced tulips, and by the necrosis size in tests on leaf disks. The relationships between the groups and among isolates were determined by cluster analysis of mean character differences using UPGMA and NJ methods. Similarity index values ranged from 0.872 to 1; on average, the index value was 0.933. A mean similarity of genotypes indicated the highest genotype uniformity of isolates obtained from a plantation with the extensive use of fungicides. 3 groups of clusters, could be observed in the obtained dendrograms. The first cluster contains exclusively genotypes of isolates obtained from a plantation with an extensive use of fungicides, the second one only genotypes of isolates obtained from a plantation protected only by the application of fungicides in the growing period and the third – one genotype of previous group of isolates and four genotypes of isolates obtained from home grown tulips without chemical protection. The most distinct differentiation between the groups of isolates was observed by the amplification using primers G4, H20 and J13. The results of this study revealed genetic similarity between isolates which were obtained from chemically protected plantations and demonstrated a higher degree of pathogenicity in comparison to the isolates which were obtained from unprotected plants and showed a lower degree of pathogenicity.
Phytophthora cambivora was isolated from the bark lesions of two 10- and 15-year-old of analysed alder trees. Additionally, Botrytis cinerea, 3 Fusarium species, Mucor spp., P. alni and Trichoderma spp. were recovered from diseased tissues. Isolates of P. cambivora from six plant species, used for inoculation of alder seedlings and plant parts, cause dthe development of necrosis. Isolate from Chamaecyparis lawsoniana was the weakest pathogen whereas those from Abies alba, Acer pennsylvanicum and Alnus glutinosa were the strongest.
Mycoherbicides are special biotechnology products which contain fungi or fungal metabolites as nonchemical alternatives thereby reducing the input of harmful chemicals to control noxious weeds. The present communication emphasizes on the potential of an indigenous isolate of Alternaria alternata ITCC 4896 as a mycoherbicide for the global weed – Parthenium hysterophorus. Of the various spore concentrations tested by in vitro Detached Leaf Bioassay, 1x106 spores/ml was the most effective inducing 89.2% leaf area damage on the 7th day and was further tested by Whole Plant Bioassay. Both in vitro Detached Leaf Bioassay and Whole Plant Bioassay exhibited a similar trend in disease development showing 50% damage at 96 hours post treatment. However, 100% mortality was observed in the Whole Plant Bioassay on the 7th day. This is the very first report on the bioweedicidal potential of A. alternata ITCC 4896 (LC#508) for use as a mycoherbicide for P. hysterophorus.
Ash dieback, caused by Hymenoscyphus fraxineus, is a serious disease of common and
narrow-leaved ash in Europe. The resistance of individual trees seems to be important for
the maintenance of ash in European forests. In this in situ wound inoculation study, the
susceptibility and differences in resistance to H. fraxineus between Fraxinus excelsior and
F. angustifolia clones were assessed. Neither of the tested clones revealed total resistance
to ash dieback; variety between the tested clones was observed. Differences in necroses
lengths were significant between clones and between two ash species. Longer necroses were
formed in F. angustifolia than in F. excelsior. Some clones exhibiting some resistance to the
pathogen were identified.
Potato leaf blight disease caused by Ulocladium atrum (Syn. Stemphylium atrum) is an important and epidemic disease in potato-growing regions of Iran. In this study, 30 isolates of the disease were collected from the main potato-growing regions of Iran and were analyzed on the basis of morphological characterization and pathogenicity. Based on morphological characteristics, all isolates were identified as U. atrum. Pathogenicity studies indicated that all 30 isolates were pathogenic on potato “Agria” to varying degrees. Five U. atrum isolates causing potato leaf blight disease, obtained from the Plant Pathology Laboratory, Isfahan Research Center for Agriculture and Natural Resources, Isfahan, Iran, were also examined in this study. A total of 35 isolates were genetically analyzed using random amplified polymorphic DNA (RAPD) and inter-simple sequence repeats (ISSR) markers. Cluster analysis using the un-weighted pair group method with the arithmetic average (UPGMA) method for RAPD marker revealed no clear grouping of the isolates obtained from different geographical regions. The groupings, based on morphological characteristics, virulence variability and RAPD analysis, were not correlated. Cluster analysis using Jaccard’s coefficient for ISSR divided the U. atrum isolates into four main groups, in which there was no significant correlation between the isolate groupings regarding their geographic location and pathogenicity. Using molecular techniques genetic variability was detected among the accessions, with cophenetic correlation coefficients (CCC) of 0.80 for RAPDs and 0.89 for ISSRs. The RAPD and ISSR marker results corresponded well, with a correlation of 0.55.
The article presents the research into hygienizing process of chicken manure using calcium peroxide (CaO2) as an environmentally friendly biological deactivation agent. The influence of the addition of CaO2 to chicken manure on the bioavailability of phosphorus was also analyzed. The process of biological deactivation using CaO2, CaO and Ca(OH)2 agents was analyzed applying the disk diffusion method. To optimize the effect of the hygienizing parameters, (CaO2 concentration, pH, temperature and time) on the reduction of Enterobacteriaceae count the Taguchi method was applied. The content of bioavailable phosphorus was measured with the Egner-Riehm method and determined with spectrophotometry. The reduction in bacterial count followed an increase in the concentration of CaO2 in a sample. The optimal experimental conditions (CaO2=10.5 wt.%, pH=9.5, T=40°C, t=180 h) enabled a significant decrease in the Enterobacteriaceae count, from 107 cfu/g to 102 cfu/g. Analysis of the samples with Egner-Riehm method showed that the phosphorus content decreased with the addition of biocide CaO2: from 26.6 mg/l (for 3.5 wt.%) to 3.5 mg/l (for 10.5 wt.%). These values were slightly higher than the content of phosphorus deactivated with Ca(OH)2 i.e., from 11.25 mg/l (for 3.5 wt.%) to 4.49 mg/l (for 10.5 wt.%). The application of CaO2 for hygienizing chicken manure enables effective reduction of Enterobacteriaceae count to an acceptable level (below 1000 cfu/g). In comparison with the traditional techniques of hygienization, the application of CaO2 has a positive effect on the recovery of bioavailable phosphorus.
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