Brown spot caused by Bipolaris oryzae is an important rice disease in Southern coast of Caspian Sea, the major rice growing region in Iran. A total of 45 Trichoderma isolates were obtained from rice paddy fields in Golestan and Mazandaran provinces which belonged to Trichoderma harzianum, T. virens and T. atroviride species. Initially, they were screened against B. oryzae by antagonism tests including dual culture, volatile and nonvolatile metabolites and hyperparasitism. Results showed that Trichoderma isolates can significantly inhibit mycelium growth of pathogen in vitro by producing volatile and nonvolatile metabolites Light microscopic observations showed no evidence of mycoparasitic behaviour of the tested isolates of Trichoderma spp. such as coiling around the B. oryzae. According to in vitro experiments, Trichoderma isolates were selected in order to evaluate their efficacy in controlling brown spot in glasshouse using seed treatment and foliar spray methods. Concerning the glasshouse tests, two strains of T. harzianum significantly controlled the disease and one strain of T. atroviride increased the seedling growth. It is the first time that the biological control of rice brown spot and increase of seedling growth with Trichoderma species have been studied in Iran

Two new arbuscular mycorrhizal fungal species (Glomeromycota) of genus Glomus, G. africanum and G. iranicum, are described and illustrated. Both species formed spores in loose clusters and singly in soil and G. iranicum sometimes inside roots. G. africanum spores are pale yellow to brownish yellow, globose to subglobose, (60–)87(−125) μm diam, sometimes ovoid to irregular, 80–110 × 90–140 μm. The spore wall consists of a semipermanent, hyaline, outer layer and a laminate, smooth, pale yellow to brownish yellow, inner layer, which always is markedly thinner than the outer layer. G. iranicum spores are hyaline to pastel yellow, globose to subglobose, (13–)40(−56) μm diam, rarely egg-shaped, prolate to irregular, 39–54 × 48–65 μm. The spore wall consists of three smooth layers: one mucilaginous, short-lived, hyaline, outermost; one permanent, semirigid, hyaline, middle; and one laminate, hyaline to pastel yellow, innermost. Only the outermost spore wall layer of G. iranicum stains red in Melzer’s reagent. In the field G. africanum was associated with roots of five plant species and an unrecognized shrub colonizing maritime sand dunes of two countries in Europe and two in Africa, and G. iranicum was associated with Triticum aestivum cultivated in southwestern Iran. In one-species cultures with Plantago lanceolata as the host plant G. africanum and G. iranicum formed arbuscular mycorrhizae. Phylogenetic analyses of partial SSU sequences of nrDNA placed the two new species in Glomus group A. Both species were distinctly separated from sequences of described Glomus species.

Many major fungal pathogens of wheat are seed-borne. Twenty-nine fungi were isolated from farmer’s seed samples in the Kohgiluyeh and Boyer-Ahmad Province in south-west Iran, by blotter, agar plate, and deep-freezing blotter methods. The purified cultures of the isolated fungi were prepared and they were identified on the basis of their morphological characteristics. The effect of these fungi on seed germination and seedling growth of four wheat cultivars, ‘Alvand’, ‘Zagros’, ‘Azar2’ and ‘Dena’, was studied in vitro by the blotter method. All of the seed samples had fungal contamination with a range of 5.83-86.16%. Twenty-nine fungal species, belonging to 13 genera (Alternaria, Aspergillus, Bipolaris, Chaetomium, Cladosporium, Curvularia, Fusarium, Nigrospora, Penicillium, Rhizopus, Stemphylium, Thielavia and Ulocladium) were identified. There were 4-6 fungal species in each sample. Fungal isolates significantly reduced the growth of root and plumule of the seedlings, but only 11 species significantly reduced the seed germination. The importance of these fungi in reducing the seed germination and seedling growth of commercial cultivars of wheat is discussed.

Fusarium wilt caused by Fusarium oxysporum f. sp. lycopersici is an important disease of tomato worldwide. The pathogen was isolated and purified from infected plants in tomato-growing greenhouses in southwest Iran during 2017. The impact of colony’s extract of four Trichoderma harzianum isolates were tested on colony growth of the pathogen in-vitro. Premium isolate colony's extract of T. harzianum was converted to nano-product by mixing with silver-nitrate. The formation of nano-particles in this product was evaluated by dynamic light scattering, and scanning electron microscopy. The impact of nano-product was tested on colony growth of the pathogen and its EC50 was determined. Then the impact of this product and silver-nitrate was tested on the disease severity in two tomato varieties in-vivo. Colony’s extract of all four isolates of T. harzianum reduced the colony growth of the pathogen, but the effect of an isolate’s extract of T.harzianum 39 was more. Produced nano-extract had EC50441.9ppm for the pathogen. It also caused a significant reduction of the disease severity in-vivo, and its effect was more than silvernitrate alone. Potential of T. harzianum nano-extract for biological control of the disease is being reported for the first time as per our knowledge.

Fungal diseases are the most important threat for rice production in the world. Rice fields were visited and sampled from diseased bushes to identify fungal diseases in Kohgiluyeh and Boyer-Ahmad province, in the south-west of Iran. Fungi were isolated from diseased tissues by Agar-plate method, and purified by single-spore or hyphal-tip methods. They were identified by studying morphological characteristics. The virulence of isolated fungi was evaluated on six dominant rice cultivars, Champa of temperate region, Champa of subtropical region, Gerdeh, Shamim, Fajr and Tarom, under greenhouse conditions. The experiment was set up in a factorial experiment in completely randomized design with four replicates. The incidence of three fungal diseases: brown spot caused by Curvularia australiensis and Bipolaris cookei, foot rot caused by Fusarium globosum and Fusarium sambucinum, and black root rot caused by Exserohilum pedicellatum, was proven in this study. Although, all of the tested cultivars significantly showed different reaction to these fungi, but the cultivars Champa of subtropical region and Tarom were resistant to foot rot as well as the black root rot and the cultivar Gerdeh was resistant to brown spot disease.