جستجوی مقالات مرتبط با کلیدواژه « آلترناریا » در نشریات گروه « گیاهپزشکی »

Tomato early blight caused by Alternaria alternata, A. tenuissima and A. solani, occurs in a wide range of environmental conditions. Effectiveness of fluxapyroxad+difenoconazole (Dagonis® SC12.5%), tetraconazole+azoxystrobin (Affiance® SC17%) and mandipropamid+difenoconazole (Carial Star® SC 50%) fungicides were evaluated in the control of tomato early blight disease in comparison with boscalid+pyraclostrobin (Signum® WG33.4%) fungicide. Dagonis® at the rates of 800, 1000 and 1200 ml/ha, Affiance® 450, 600 and 750 ml/ha, Carial Star® 400, 550 and 700 ml/ha and Signum® 500 gr/ha and the control group (no fungicide application). The experiments were carried out under the field condition in Fars and Hormozgan provinces, and under greenhouse condition in Alborz province. The disease severity index and area under the disease progress curve were calculated. The results showed that Affiance® at the rates of 600 and 750 ml/ha with 48-82% efficacy, Dagonis® at the rate of 1200 ml/ha with 50-70% efficacy and Signum® at the rate of 500 gr/ha with the efficacy of 48-75% were effective in controlling tomato early blight disease. Although Carial Star® fungicide with the amount of 700 ml/ha was less effective (45-55%) as compared to aforementioned fungicides, but its average efficiency can be justified. Therefore, Affiance®, Dagonis® and Signum® fungicides, at the rates of 600, 1200 ml/ha and 500 gr/ha, respectively, and Carial Star® fungicide (in the early stages of the disease) at the rate of 700 ml/ha are recommended to control tomato early blight disease.

Early blight disease on potato is caused by Alternaria solani and A. alternata. The damage rate of this disease is variable and has been reported between 5-78%. In this study, the effect of Propamocarb+fenamidone SC45%, Chlorothalonil WP75%, Azoxystrobin+difenoconazole SC32.5%, Boscalid+pyraclostrobin WG33.4%, Cymoxanil+copper hydroxide, Sodium bicarbonate, Calcium chloride, Cang Mei and Pars Basil in the laboratory and greenhouse was investigated. Generally, all of these treatments inhibited mycelial growth of A. solani and A. alternata. Azoxystrobin+difenoconazole and Boscalid+pyraclostrobin with concentration of 30 ppm and 100 ppm, respectively with 99% had the highest of percentage inhibition on the growth of A. alternata mycelium. The lowest effective treatment in mycelial growth inhibition of this species was Cymoxanil+copper hydroxide with concentration of 150 and 200 ppm. In greenhouse, Azoxystrobin+difenoconazole with concentration 1/1000 and Pars Basil with concentration 1/100 were the most and the least effective treatment in disease severity index of A. alternata, respectively. Azoxystrobin+difenoconazole, Sodium bicarbonate and Boscalid+pyraclostrobin with concentration 30, 20000 and 100 ppm, respectively decreased the growth of A. solani mycelium by 99%. Cymoxanil+copper hydroxide with concentration 150 and 200 ppm as the lowest effective treatment, inhibited the A. solani mycelium by 26%. In greenhouse, Azoxystrobin+difenoconazole and Boscalid+pyraclostrobin with concentration of 1/1000 and 0.5/1000, respectively decreased the disease severity index of A. solani by 100%. Cang Mei with concentration 1/100 decreased the disease severity index of this species by 5% with no difference with the control.

Application of chemical fungicides is the primary method of tomato early blight disease management in Iran. In this study, the efficacy of CangMei biofungicide in doses of 0.75, 1 and 1.25 ml L–1 were assessed on the control of this disease alongside with Iminoctadine Tris and control without the use of fungicide. The experiment was carried out in Fars and Khorasan Razavi provinces according complete randomized blocks with five treatments and four replicates. The first spraying was performed after flowering stage, the second one was after the first symptoms of the disease was observed and repeated every 7 days up to 5 times. The effects of pesticides were assessed six times on the development of the disease on the leaves based on disease severity and the data was analyzed using SAS software. The results showed the best treatment to control of tomato early blight disease was Belkute®. Cang Mei bio fungicide in dose of 1.25 ml L–1 had the greatest effect among examined doses and reduced Area under disease progress curve (AUPDC) 30.16% and 33.21% in Fars and Khorasan Razavi respectively. Due to the destructive effects of chemical fungicides, Cang Mei could be recommended in dose of 1.25 ml L–1 to produce healthy crop..

Trichoderma species are the main causes of decomposition and decay of agricultural residues and are considered for the control of plant pathogens, especially fungi and nematodes in the world. Trichoderma species have the ability to produce microbial enzymes such as xylanases, which are used in the paper and food processing industries. These enzymes improve the digestibility of nutrients in certain diets in ruminants and poultry, where there is no digestive enzyme that can digest the complex carbohydrates in the cell wall. These enzymes have the power to digest and hydrolyze these substances. South khorasan province due to hot and dry climate, water shortage and successive droughts, saline water in agriculture, pests and diseases, soil with low fertility for planting irrigated wheat needs cultivars resistant to these stresses. Narin cultivar is the latest cultivar introduced for this province. The characteristic of this cultivar are more compatibility with salinity stress areas and relative maturity with other wheat cultivars.
In order to investigate the effect of simultaneous use of Trichoderma harzianum and plant mulch on yield and physiological characteristics of wheat of Narin cultivar and its effect on the interaction of this cultivar with Alternaria alternata in 2019-2020 in Birjand Faculty of Agriculture Research Farm an experiment asComplete randomization block design was performed with four replications. Treatments included control (without application of Trichoderma), Trichoderma as soil application, Trichoderma as leaf application in granulation stage, Trichoderma application as soil and leaf application in granulation stage. In the granulation stage, each experimental unit was divided into two parts and Alternaria leaf spot pathogen treatment at two levels (inoculation in the granulation stage and without inoculation) was considered as a sub-factor in the experiment. The purpose of using the pathogen treatment was to evaluate the effect of Trichoderma in the presence of the pathogen. This fungus was prepared from the archives of the Plant Pathology Laboratory of Birjand University of Agriculture, which had previously been isolated from the wheat of this province. To inoculate this pathogen, a suspension with a concentration of 106 spores per ml of A. alternata was used from a 7-day fungus colony on PDA medium and its effect on physiological traits (including total phenol, chlorophyll a, chlorophyll b, carotenoids, total chlorophyll) were investigated. To investigate the effect of different applications of Trichoderma on Narin cultivar from another part of the plot without pathogen treatment was analysis of growth traits, yield and yield components including chlorophyll index, including green and dry stem height, spike length, weight, grain yield, biological yield, number and weight of grains per spike, spikes number and weight per unit area were measured.
The aim of using pathogen treatment was to evaluate the biological control of Alternaria wheat leaf spot agent by T. harzianum in different methods by using Trichoderma in the presence of Alternaria in comparison with the absence of Alternaria and its effect on physiological traits (including total phenol, chlorophyll a, Chlorophyll b, carotenoids, total chlorophyll) were evaluated. No symptoms of necrosis or leaf chlorosis were observed after pathogen inoculation. Analysis of physiological traits (total phenol, chlorophyll a, chlorophyll b, carotenoids, total chlorophyll) showed that only the simple effect of inoculation or non-inoculation of Alternaria with Trichoderma significantly different (P <0.05) in terms of total phenol content. Due to the presence of Alternaria as a pathogen, it may lead to a reaction of the plant's defense system, and Trichoderma can also increase phenolic compounds to counteract the pathogen. Analysis of growth traits, yield and yield components showed that Trichoderma treatment had no significant effect on any of them.
This study, for the first time showed that A. alternata can cause disease on wheat Narin cultivar. Also, this research studied the effect of T. harzianum on physiological and functional characteristics of wheat Narin cultivar and results demonstrated that T. harzianum can have little effect on these characteristics of Narin cultivar. Concomitant use of Trichoderma in soil and leaves had a greater effect than separate application in roots or leaves. Also, according to other research, the effect of trichoderma varies depending on the environmental conditions including temperature and humidity, soil texture and structure and the type of wheat cultivar.

Early blight incited by Alternaria spp. is one of the destructive diseases of tomato which causes considerable crop yield losses. Biological control of the disease with epiphytic fungi as phyllosphere competent microorganisms is a suitable alternative to chemical pesticides. In order to isolating the fungi, healthy tomato plants were collected and small pieces of leaves and stems were placed in distilled water on a shaker and the aliquot was cultured. In search for biocontrol strains, isolated fungi were screened against the fungal pathogen (Alternaria alternata SN1–1) using dual culture as well as the volatile and non–volatile metabolites tests in vitro andeffective isolates were selected to study their efficacy on disease control under greenhouse conditions. Conidial suspension of epiphytic fungi was sprayed two times on the aerial parts of the plant in greenhouse. Two weeks after inoculation of the pathogen, the disease severity was evaluated based on a 0–9 scale. Results of screening test showed that epiphytic fungi inhibited the mycelial growth of the pathogen in various degrees. Maximum inhibition in dual culture, volatile and non–volatile metabolites tests were 70%, 53% and 68%, respectively. In greenhouse, the least disease indexes were recorded for the isolates F1–22 and P4––1 (81.4% disease control) together with P1–1 and P2–1 (74.4% disease control). Isolates F1–22, P4–1 and P2–1 identified as Trichoderma harzianum and isolate P1–1 identified as Trichoderma longibrachiatum.

The Lysin motif in receptor-like kinases (LysM-RLKs) bind to chitin or chitin components of the fungal pathogen cell wall to perceive their invasion. To study the LysM-RLK domains of potato genome involved in Alternaria solani response, the putative LysM-RLKs were bioinformatically assessed, sequenced and their expression levels were measured in a susceptible (Russet Burbank) and relatively resistant (F06037) genotypes, following inoculation of the pathogen. A total of 35 putative LysM-RLKs were detected in potato genome, of which 26, 5 and 4 LysM-RLK had none, one and two LysM motifs, respectively. Among 9 receptors containing LysM-RLK domains, two proteins showed a significant overexpression following A. solani infection.
PGSC0003DMP400061331 protein with two LysM motifs had a higher expression level than PGSC0003DMP400060418 protein with one LysM motif. Both proteins had 98% and 81% coverage with Arabidopsis thaliana CERK1 protein, respectively. Multiple sequence alignment (MSA) of LysM motifs from both proteins of two potato genotypes with that of Arabidopsis thaliana CERK1 revealed no difference between genotypes with respect to LysM motif sequence. Interestingly, the LysM motifs from PGSC0003DMP400061331 protein had an “NRD” insertion as compared to its second LysM motif, PGSC0003DMP400060418, and Arabidopsis taliana CERK1 LysM motifs. Such changes may have occurred through deletions or duplications. Alteration of DNA sequences by genome editing methods may shed light on the role of these genes in the field of resistance or susceptibility to A. solani leading to generation of resistant transgenic plants to devastating fungal diseases.

Potato is one of the major Agronomic crops in Kurdistan province. Many fungi have been reported as the causal agents of tuber, crown and root rot and canker on potato plants. The objective of this study was to identify fungal agents associated with tuber, crown and root rot and canker of potato. Samples were collected from diseased plants in East of Kurdistan (Ghorveh and Dehgolan) during cropping season in 2014. Samples were first washed under tap water and then sliced to 0.5-1 cm pieces, surface sterilized and plated on general or selective culture media. In total 151 isolates were obtained from tuber, crown and roots of infected potatoes and purified using single spore or hyphal tip. Fungal isolates were identified based on morphological and sequence data of ITS, RPB2 and TEF loci. Finally, based on morphologic characters and DNA sequence data 10 species belonging to four genera were identified including Alternaria arborescens, A. alternata, A. atra, A. embellisia, Colletotrichum coccodes, Fusarium equiseti, F. redolens, F. tricinctum, Neocosmospora rubicola and N. haematococca. Among the identified genera, Fusarium with 93 isolates was the most frequent genus.

Effect of chlorothalonil (Daconil SC 725) and famoxadone + cymoxanil (Equation Pro WG %52. 5) fungicides in control of Early Blight disease of tomato were evaluated under field conditions. The experiments were carried out in a Randomized Complete Blocks Design (RCB) with eight treatments and four replications during two years in Karaj. Experimental plots inoculated with causal organism at the beginning of flowering stage. Spraying of plots was started by early symptoms seen and continued with 5، 7 and 10 days intervals. Disease Severity Index (DSI) assigned by Foliage Protection Percentage (FPP) with causal agent by using Horsfall and Barratt method، before each spraying، and the later assessing was done 14 days after last spraying. Yield of each plot was measured، and numbers of fruits for each plant were counted. Analysis of variance of two years data، were done at Randomized Complete Blocks Design (RCB) by SAS software، and means were compared with Duncan multiple range test. Area under the Disease Progress Curve (AUDPC) was calculated using five separate disease assessments data، and effects of treatments on disease progress were also studied. The results revealed that there were significant differences between treatments in DSI in all assessments، AUDPC and yield but there was no significant difference between treatments in number of fruits. Also the results for 5th assessment and AUDPC in both study years showed that Daconil SC 725 (3 L/ha) and Equation Pro (450 g/ha) with lowest mean based on DSI were the best treatments to control of Tomato Early blight disease. Daconil SC 725 (3 L/ha) and Equation Pro (450 g/ha) were decreased DSI by 80. 26 and 80. 6 percent in compare to control، respectively. In terms of mean fruit weight، Equation Pro (450 g/ha) and Daconil SC 725 (3 L/ha) were increased yield 65. 03 and 64. 17 percent in compare to control، respectively، and were the best treatments.