نشریه گیاه پزشکی کاربردی
سال چهارم شماره 2 (پیاپی 14، شهریور 1394)

In this study the reaction of 27 tomato cultivars available in the country with isolates of Alternaria alternata f.sp. lycopersici collected from different regions were evaluated. For this purpose, to collect isolates from different regions and the pathogenicity of tomato varieties Pete Early-CH (susceptible to stem canker) was used. To identify the pathogen measurements were carried out in both macroscopic and microscopic. In this way, the color of the Colony and other macroscopic properties of the medium were examined under a microscope to examine the treatment of fungal spores and conidiophores and 100 were measured for each isolate was determined as the average. Other specifications, such as number of walls, length, width and color were investigated. A sample collected for testing of isolates susceptible cultivar was selected based on disease severity index. Selected varieties of seedlings after planting and transferred to pots in a greenhouse with suspension isolates of the fungus were inoculated in separate tests to measure disease incidence (Disease severity index) on the stem, after the elapse of the incubation period and the rise . Results of the evaluation showed that three varieties of stem canker Ps 550 and Xamen and Super Set in evaluating the area under the curve progression of the disease in stem cultivars, showed the lowest levels of development and were identified as resistant varieties. In order to study the fungus producing extracellular compounds and their role in the disorder, disease-causing bacteria in the PDB (infantry, dextrose liquid culture medium potatoes) Potato Dextrose Broth were killed. Tomato seedlings and leaflets for susceptibility to extracellular secretions (toxins) were evaluated. .

Tobacco Sore Shin caused by Rhizoctonia solani is an importatnt agent that distributed worldwide and causes yield losses in tobacco growing countries. One of the new methods of plant disease control is application of plant extracts. This research was performed to evaluate the antifungal activity of plant extracts on the causal organism of tobacco Sore Shin disease. The study was conducted on a completely randomized block design with 7 treatments and four replications in Tirtash Research and Education Center in 2014. Treatments included catmint, tobacco varieties (Burley21, K326 and Basma 178-2) extracts with concentrations of 2 per 1000, nicotine with concentrations of 1 per 1000, Thiophanate methyl fungicide with concentration of 25 gram in 100 liter water and the check sprayed with water. The results of variance analysis showed that the effect of plant extracts on control percentage of tobacco Sore Shin disease agent was significantly different at 1% probability level. Mean comparison of treatment showed that Thiophanate methyl fungicide, catmint and tobacco, Burley 21 cultivar extracts had the most effect in disease control with 84.95, 78.32 and 73.3 percent respectively. Therefore, the extracts of catmint and tobacco can be considered as natural fungicide for control of causal agent of tobacco Sore Shin.

The use of natural compounds for disease control and prevention has been considered because of the benefits. Using herbal essences has been developed due to having medicinal properties, antifungal, antibacterial and antioxidant secondary metabolites in the control of pathogens. In this study, the performance of three plant essential oils Cumin (Cuminum cyminum), cinnamon (Cinnamomum zeylanicum) and peppermint (Mentha sp.) and soluble chitosan in the prevention and treatment of rice sheath blight caused by the fungus Rhizoctionia solani in vitro and in Ziveh, were studied. This experiment was done in a completely randomized design with 500 treatments and 3 replications. Treatments consisted of three factors essential oils, each in five different concentrations (100, 200, 400, 600, 800, 1000 ppm) and the Factor chitosan in two concentrations 800 and 1000 milligram per liter and also two control included a positive control (culture medium along with tilt PDA) and negative control (dextrose agar medium potatoes without oil). Each treatment consists of three replicates each also includes three petri dish (for all treatments and positive and negative controls), respectively. Inhibition of different concentrations was determined using the Abbott formula. The full minimum inhibitory concentration of essential oils (MIC) and minimum fungicidal concentration of essential oils (MFC) was also calculated. The factorial experiment was considered in a completely randomized design with three replications in which every essence as a factor and different concentrations of essential oils, different levels of each factor. The results showed that essential oils of cinnamon and cumin inhibited 100% of the growth of R. solani were in effect concentrations ppm 200. The essential oil and chitosan 100% inhibition at concentrations of 600 and 1000 were one of their own. In addition to these three extracts of cinnamon, cumin and mint with a percentage of inhibition, respectively, 67/81, 50/82 and 33/83 showed similar results, with 50% inhibition chitosan least inhibition of pathogenic fungi on plant show.

Population fluctuation of sunn pests’ parasitoids (Scelionidae and Encyrtidae) was studied in 5 different localities of Varamin including, Javad-Abad, Dehmacin, Gharchak, Asgar-Abad and Pishva. Seven parasitoid species including, Telenomuschloropus, Trissolcusbasalis, Tr. grandis, Tr. rufiventris, Tr. semistriatus, Tr. vassilievi and Ooencyrtustelenomicida were collected from the mentioned regions. Upon the samplings in Gharchak, 4 species, T. semistriatus, T. grandis, T. Vassilievi and T. Rufiventris, were collected which of these T. semistriatus and T. grandis were determined as dominant species. Mean percent parasitism of T. semistriatus was higher than the other species and the highest parasitism (44.63%) was obtained in 22 May 2014. In Pishva, 5 parasitoids, T. grandis, T. vassilievi, T. semistriatus, T. chloropus and T. Basalis, were collected, which T. grandisand T. vassilievi were the dominant. The parasitism of these two parasitoids were started in 10 April 2014 and the maximum parasitism of T. grandis(27.89%) in 22 May 2014 and for T. vassilievi (22.39%) in 29 May 2014. Parasitoids of sunn pest in Javad-Abad were identified as T. rufiventris, T. grandis and Telenomus chloropus which of these, T. rufiventris was determined as the dominant species. The beginning of its parasitism activity was observed in 17 April 2014 and its maximum (26.44%) in 7 May 2014. The collected species in Dehmacin were included T. semistriatus, T. vassilievi, T. grandis and O. telenomicida which 2 species T. semistriatus and O. telenomicida were the dominant. The maximum percent parasitism was obtained in 22 May 2014 for T. semistriatus and 29 May 2014 for O. telenomicida. Six parasitoid species including, O. telenomicida, T. rufiventris, T. vassilievi, T. grandis, T. semistriatus and T. simony were collected from Asgar-Abad, which of these 3 first species were the dominant species. The highest percent parasitism for T. vassilievi(16.68%) and T. rufiventris (13.21%) was obtained in 22 May, 2014, and for T. grandis(23.72%)in 5 June 2014. Regarding to sex ratio of parasitoids, mean percent of emerged females was more than the male production in all sampled regions.

Bean anthracnose caused by Colletotrichum lindemuthianum (Sacc. and Magnus) Briosi and Cav., is one of the major diseases of common bean in relatively cool, wet cultivation areas of tropical and temperature regions. Crop losses can be severe or total, especially when susceptible cultivars are grown in a conductive environment for disease. In this study, first different fungal isolates were obtained from the west and north areas in Iran, purification and pathogenicity done on susceptible cultivar “Talash” with spore suspension with concentrations of 1-2 ×10 6 spores/ml on leaves in the greenhouse. Then the virulence of isolates conducted like pathogencity method on Talash cultivar. Disease severity index, 15 days after the spore spraying was rated using the method described by Van Schoonhoven and Pastor-Corrales. A total of 11 isolates C. lindemuthianum were obtained based on the results of sampling from different regions that had mostly high virulence, with different severity indices of the disease, ranging between 22.2 to 98. In reaction study of 40 bean cultivars or genotypes to causal agent in greenhouse conditions, six cultivars (Naaz, Pachebaghela- ragehghermez, Almas, Shekoofa, Daneshkadeh, Dorsa) and four genotypes (920040, 940040, 21676 and 31167) with infection degree less than 3 showed resistant “R” (25% of all varieties and genotypes) whereas eight genotypes or varieties showed moderately resistant reaction “MR” and the rest were considered as susceptible “S”.

Plant pathogens cause severe economic losses in agricultural crops and the environment around the world. The use of appropriate, cost-effective and none polluting control procedures on plant diseases is still developing. In recent years, cold plasma sterilization plant pathogens have been considered one of the most important research topics in the world. Ionized gas called plasma is referred to as a substantial portion which has lost all or a remarkable amount of its atoms and electrons and positive ions. Such as reactive oxygen species, OH free radicals and etc. which comes fungi disease by the destruction of fatty asides and protein molecules placed inside the cell membrane of pathogenic fungi which brings to plant infection. In this review study, the cold atmospheric plasma and its effects are considered on plant pathogenic fungi as a tool used for effective control preventing the spread of pollution which is due to be addressed