Plant Pathology Science

Role of Arbuscular Mycorrhizal Fungi in Plant Diseases Management

Mehdi Sadravi

Arbuscularfungi are root symbiontsof 80% of plants, such as most field crops and fruit trees. They establish in root tissue, arbuscule in endodermis cells, and an extramatrical fine hyphal net. These fungi byincreasing absorption of water and nutrient elements for plants, making changes in chemical constituents of plant tissues, competition with pathogens for nutrients and establishment site, structural changes in roots, alleviation of environmental stresses, and increasing population of useful bacteria in soil, help management of diseases caused by fungi, fungal like organisms, nematodes, bacteria, phytoplasmas and physiological disorders. Collection, identification, purification, propagation, and inoculation of these useful fungi to plants, can decrease usage of chemical fertilizers and pesticides that are harmful to consumers of agricultural products as well as to the environment

Application Yarrow, Bead-Tree and Neem in Control Root-Knot Nematode Meloidogyne incognita

Abbas Salahi Ardakani

In order to control plant parasitic nematodes, in spite of chemical costs, some may have residue in yield, some kill the natural enemies of nematodes, and many of them may pollute the environment. Based on research carried out by oil, seed kernel extract and powder, and meal of neem, complete bead-tree seed extract and powder, yarrow aerial parts extract and powder, can cause mortality of these onstage juveniles of the root-knot nematode Meloidogyne incognita. The effect of these plants materials on the nematode mortality compared with control and showed statistically significant difference at the level of 1%. Application of these plants materials maybe reduces of chemical pesticides and risks of their using.

Bacterial necroticand leaf spot diseaseof banana

Majid Amani

In 2005, Circular to elliptical brown necrotic leaf spots, were observed on young leaves of Banana(Musa acuminata L.) plantion under plastic cover in Mazandaran&Gorgan provinces. The rhizomes and pseudostems were not affected. A gram-negativebacterium with yellow mucoid colonies was isolated from the leaves on sucrose and glucose nutrient agar. All isolates were negative in oxidas, and positive in catalase reaction. Non of isolates did not produce green or blue pigment on KB medium. On the basia of phenotypic charachteristics pathogenicity test was confirmed with inocoulation of bacterial suspension to Banana plants. The causal agent of bacterial necrotic and leaf spot of banana was recognized asXanthomonascampestris. This is the first report ofbacterial necrotic and leaf spot of banana in Iran.

Role ofTrichoderma species in increase plants growth

MirMaesum Iraqi

In last decades, development of Biology science, importance of protection of environmentand high demand to the nutrients is caused that usage of the biological materials, in order to increase crop yield, have been viewed by researchers. Some of the Bacilli, Rhizobia and Trichoderma species are distinguished as Plant Growth Promoting. These micro-organisms with colonization and abundant sporulation in soil especially in rhizosphere of most of the cultivated and non-cultivated plants not only decrease the pathogenic agents, but also increase growth of the plants by bio-chemical mechanisms. With attention to isolate and study of many Trichoderma species in Iran, importance of performance researches about plant growth promoting effects of theTrichoderma species is necessary. In this paper, review of the plant growth promoting effects of Trichoderma is presented.

Applicationfungal like Pythiumoligandrum as a biofungicide

Reza Mostowfizadeh-Ghalamfarsa

The importance of plant protection in modern agriculture increases as crop yields and concerns about production quality rise. Plant protection should be sufficiently effective, affordable and considerate of the environment. The integration of biological and chemical control has a potential for success because of a possible synergistic effects. It is necessary to look for organisms suitable for use in biological control, and in order to study the mechanisms of their action and the optimal conditions for incorporating such agents in plant protection and integrated management systems. One of such microorganisms is PythiumoligandrumDrechslerthatbelongs to the phylumOomycetes. This soil-resident saprophytic microorganism can be parasitic and hyperparasitic on many fungi within the same or other classes. The antagonistic activity of P. oligandrumis a multifaceted process which depends on the target species involved. P. oligandrumis nonpathogenic on 12 species of crops that belong to six families. It occurs on the root surface together with plant pathogenic fungi, predominantly in the regions of hypocotyl – taproot without penetrating the plant tissues. The plant growth is reportedly stimulated by this species. P. oligandrum can be utilized for biological control on a wide spectrum of crop plants. Different methods of application have been developed. The most effective activity of this microorganism is the mycelial growth inhibition of the plant pathogenic fungi.

Methodofdetectionmancozebfungicide residue in cucumber fruit

Safarali Mahdian

Vegetables are attacked by different pests and diseases during their growth. Some fruits such as cucumber have sprayed regularly against diseases like Pseudoperonosporacubensisspecially in humid areas, and after a short time the cucumber are picked up and the amount of pesticide residue are measured and comparing with Maximum Residue Level (MRL). In this research the amount of Mancozeb fungicide has quantified in cucumber samples in Sari district. So in this order 26 samples of cucumber are collected and were carried to the laboratory. Samples of fruits are weighted and washed by using of n- hexan in Suksoleh device. After concentrating the obtained solution put in spectrophotometer set for measuring the optical density with 280 nanometer wave lengths and the amount of uv absorbance of samples and standard solutions were checked. The obtained numbers was changed into all right amount of mancozeb by using Excel software and Cx= α. Cs / β. Vx equation. Results showed that the amount of remained mancozeb fungicide was less than maximum residue limit in 77 percent of samples and more than maximum residue limit in 23 percent of samples in these periods. Also it defined among the samples which have had residue higher than standard limit, just 2 samples have been increased more than 1 milligram per kilogram.

Introduce five diseases of bell pepper in the Isfahan Province

Mehdi Nasresfahani

The Pepper (Capsicum annuum) is one of the important field crops in the worlds, which its cultivation has been developed, because of its food value and consumptions. But, there are certain diseases, which limited the growth and productivity, out of which the fungal diseases are of high severity. Thus, for this very purpose, a survey was conducted in the pepper growing areas including field and glass houses for fungal diseases identification in Isfahan provinces. The infected pepper plants were collected in the plastic bages and transferred, into the lab. The macro and microscopic studies indicated that there are severed fungal diseases infecting the pepper plant on the areal parts, including Powdery mildews, Downy mildews, Sclerotinia stem rot, early blight and Botrytis molds. Except the Downy and Powdery mildews being obligate parasite, which cannot be cultured the rest were culture from the margin in the infected parts, where the disease were under development on PDA for purification and identifications through tip culture. The results revealed that, there are several fungal species involving including Peronosporatabacina for Downy mildew, Levielullatauricafor Powdery mildew, Early blight, Alternariaalteanataand A. solani, fruit rot, Botrytis cinerea and stem rot due to Sclerotiniasclerotiorum from areal parts.