Pistachio is one of the most important horticultural products in Iran which its production is always affected by biotic and abiotic limiting factors. Armillaria crown and root rot caused by Armillaria mellea, is an important disease in pistachio orchards, which causes the death of fertile trees. Control of the disease is difficult, costly and rarely successful. Symptoms of the disease in shoots of affected trees includes yellowing, early defoliation, sudden wilting, dieback of branches and reduction shoot growth. These symptoms, together with the decay and browning of woody tissues and the formation of white to creamy mycelial sheets in the roots and crown, as well as the observation of rhizomorphs of the fungus, are sufficient evidence for definitive diagnosis of Armillaria crown and root rot in pistachio trees. The infection process begins with the growth of hyphae or rhizomorphs and their firm attachment to the surface of the roots. The pathogen uses a combination of methods such as mechanical pressure, toxin production, and cell wall-degrading enzymes to penetrate the root tissues. Successful control of the disease is possible only by combining chemical, cultural, biological control methods and use of resistant rootstocks and cultivars due to delay in diagnosis of the disease before the spread of the pathogen in plant and soil and the appearance of symptoms, the presence of an extensive network of rhizomorphs at a distance from the tree and deep in the soil and formation of the mycelium beneath the plant bark or inside dead wood.

A total of 109 fungal isolates were collected from the wheat fields in various regions of Lorestan province, during 1994-95 and in a complementary survey in 2003-04. All isolates were recovered from samples having crown and root rot symptoms. Of these, 45 isolates belonged to Fusarium and the remaining belonged to other fungus genera. Fusarium verticillioides, F. proliferatum, and F. equiseti had the higher frequencies with 62.2, 4.5, and 4.5% of the isolates, respectively. Fusarium avenaceum, F. semitectum, F. sambucinum, F. chlamydosporum, F. lateritium, F. acuminatum, F. subgulatinans, F. reticulatum, and Fusarium sp., were the least frequents. Among other fungi, isolates of Bipolaris hawaiiensis, and B. sorokiniana comprised 18.4 and 13.8 % and Rhizoctonia solani comprising 1.8 % were the most and the least frequents, respectively. The species F. reticulatum, Fusarium sp., Bipolaris hawiiensis, Alternaria triticina, and Curvularia senegalensis isolated and their pathogenicity was confirmed for the first time from the root and crown of wheat in Iran. Pathogenicity of F. lateritium and F. subglutinans on wheat is also reported for the first time.

In this study, 99 Rhizoctonia solani isolats were isolated from some pistachio nurseries in Kerman province. Fungus was isolated from infected plant tissues and soils. Isolates were identified according to the morphological characters of the hyphae, cellular nuclei number of young hyphae, and their anastomosis groups. Results revealed that 96 isolates were multinucleate (MNR) and 3 of them binucleate (BNR). MNR isolates belonged to AG-4, and BNR isolates to AG B-I. Pathogenicity of the isolates was carried out on pistachio plants and the MNRs were pathogenic on pistachio but their virulence levels were significantly different. None of BNR isoltes were pathogenic on pistachio. The applicability of biological control as a method for combating disease was investigated in lab and greenhouse experiments using BNR isolates. In dual culture tests, no hyphal lysis was observed and the only interaction was coiling of the bc agent hyphae around the R. solani hyphae. In greenhouse experiments, coinoculation of the plants by BNR and R. solani did not control the disease. On the other hand, when plants were inoculated by BNR, two weeks before inoculation with R. solani, the disease was reduced considerably.

Gummosis (Crown and root rot) is the most important disease of pistachio trees caused by different species of Phytophthora which destroy significant numbers of fertile and non-fertile trees each year in Iran. Different approaches have been applied to reduce the severity and incidence of the disease. In recent years, biological control as an eco-friendly approach has been increased in the world. The effectiveness of Talk powder and Wheat bran formulations of five Pseudomonas strains (T17-4, VUPF760, VUPF5, VUPF506, and CHA0) was assessed on seedlings inoculated with Phytophthora drechsleri under greenhouse conditions. The highest and lowest reduction rates of disease severity belonged to VUPF760 and VUPF506 with 55 and 11%, respectively compared to the control and other treatments. Seedling inoculated with bacterial strains had higher heights, fresh and dry weights of shoot and roots. VUPF5 increased the ratios of height, fresh and dry weight of shoot and root by 1. 4, 1. 3, 1. 1, 1. 2, and 1. 1 respectively, compared to non-inoculated control seedlings.

In the summer of 2022, sansevieria plants with symptoms of root and crown rots were detected in greenhouses of Isfahan province, Iran. Symptomatic tissues of the root were cultured on CMA-PARPH. Recovered oomycete isolates were purified by single-zoospore technique on WA. The baiting method using citrus leaf disc was also used to isolate Phytophthora spp. isolates from the soil around roots. Four isolates were obtained directly from infected root tissues and two isolates from soil. Fungal isolates were identified based on morphological characteristics and molecular data of β-tubulin (βtub) and translation elongation factor 1-alpha gene (tef1-α) genes. According to the morphological and phylogenetic analysis, all isolates were recognized as Phytophthora occultans. Koch's postulates were completed and confirmed that Phytophthora occultans isolates were responsible for sansevieria root and crown rots. To our knowledge, this is the first report that Phytophthora occultans associated with root rot of sansevieria in Iran and probably in the world.

Root and crown rot is a common tomato disease in the major production areas of Hormozgan province. The present study was conducted to isolate, identify, and determine the frequency of fungal agents associated with tomato root and crown rot in Hormozgan province. In total, 984 fungal isolates were obtained from tomato plants with yellowing, wilting, and root and crown rot symptoms. Identification of the isolates was done based on the morphological characteristics and the comparison of the obtained sequences of the ribosomal internal transcribed spacer region (ITS-rDNA) and parts of the translation elongation factor-1 alpha (tef1-α) gene with relevant sequences available in GenBank. According to the results, the highest frequency belonged to Fusarium oxysporum isolates (73%), and afterward to Rhizoctonia solani and F. acutatum species with eight and one percent frequencies, respectively. The results of the pathogenicity tests of the fungal species on tomato seedlings hybrid Sunseed 6189 at the stage of four true-leaves revealed that all three species were pathogenic on tomato seedlings and caused root and crown rot, yellowing, and death of the plant aerial tissues. Pathogenic isolates of F. oxysporum were identified as F. oxysporum f. sp. radicis-lycopersici using sprl-specific primers. To the best of our knowledge, this is the first report of F. oxysporum f. sp. radicis-lycopersici on tomato in Hormozgan province, and the first report of F. acutatum as tomato root and crown rot agent in the world.

Sampling was done from sesame plants from research field of Vali-e-Asr University of Rafsanjan. Rhizoctonia solani was isolated and identified. These isolates were all multi-nucleotide, pathogenic and belonging to the AG3 anastomosis group. The possibility of biological control of Rhizoctonia rot of sesame was investigated using of Trichoderma harizianum and Rhizophagus intraradices. This experiment was conducted with 7 treatments (inoculated soil with Trichoderma, inoculated soil with arbuscular mycorrhiza, inoculated soil with Trichoderma and arbuscular mycorrhiza, inoculated seed with Trichoderma, inoculated seed with arbuscular mycorrhiza, inoculated seed with Trichoderma and arbuscular mycorrhiza and control without antagonistic agents) and 4 replicates for each treatment. According to the results obtained from different treatments, the inoculated soil with Trichoderma(mean=0. 19), the inoculated soil with Trichoderma and arbuscular mycorrhiza(mean=0. 193) and the inoculated seed with Trichoderma and arbuscular mycorrhiza(mean=0. 11) showed the highest amounts of disease control.

Phytophthora root and crown rot of safflower (Carthamus tinctorius) is regarded as one of the main soilborn diseases of this crop in Iran. Sampling and isolating of the causal agent was performed from farms in Ghazvin, Karaj and Isfahan. A frequently isolated oomycete called Phytophthora drechsleri was determined as the major pathogen of the disease. Twenty different genotypes of safflower were inoculated in mature and seedling stages using three different methods.Hypocotyls and cotyledons of 10-days seedlings were inoculated by putting a small disk of freshly prepared mycelial mat of pathogen. The results of two inoculation methods suggested that cultivars and lines including Gol sefid-e-Esfahan and KW10 in the hypocotyle method and local Ajabshir line in the second method of cotyledon inoculation had the highest level of tolerance to the pathogen. Results of detached leaf method indicated that the lines local Ajabshir, KW6, Golsefid Esfahan, Varamin295 and Zarghan279 have the highest level of tolerance to disease, respectively.The results suggest that local Iranian lines should have higher level of tolerance to the disease.