This investigation was carried out to study the fauna of the stone fruit trees aphids during 1999-2000. The specimens were collected once a week from infested leaves and branches of the trees of plum, peach, apricot, almond and cherry from Mashhad orchards. In this study 16 species of aphids were collected and identified from the stone fruit trees ef this area and are as follow: Aphis citricola * V d G., A. craccivora* k., A. gossypii * G.,  Brachycaudus amygdalinus s., B. cardui (L.). B. dicaricata * s., B. hlichryi(K.), B. persicae * (P), B. pilosus ** (M.). B. Prunicola (K.), B. schwartzi (B.). Hyalopterus pruni (S.),  Pterochloroides persicae (CH.). The species that is marked with*, are reported on new hosts (1-apricot, plum., peach; 2- plum., sloe tree., Prunus divaricata caspica k.-E; 3-Almond; 4-sloe tree; 5-Plum., sloe tree; 6- plum., peach ); and the species that is marked with**, is a new record for Iran.    

Bacterial canker and leaf spot are typical symptoms and of the most important diseases of stone fruit trees in world and in North your country. Significant management of plant disease is possible by identification and diagnosis plant pathogenic casual and associated agents. Various samples of canker and leaf spot tissues during 2007-2008 collected from different orchards of stone fruit trees of Golestan province and pathogenicity tests was demonstrated on peach young branches and leaf tissues by various bacterial isolates. Based on the morphological, nutritional, biochemical, physiological, total cellular protein pattern and PCR reaction with d21 and d22 primers Pseudomonas syringae pv. syringae (Pss), and Xanthomonas arboricola pv. pruni identified as casual agents of bacterial canker in this province.Pss was the major agent disease on the east regions such as Ali-Abad and Azad shahr but in west regions such as KordkooyXap was major agent.P.viridiflava isolated from gorgan areas only as associated agent with disease. This research is the first report on Xap, the casual agent of bacterial canker in stone fruit trees Golestan Province and also first report on P. viridiflava, as associated agent with bacterial canker stone fruit trees on the north regions Iran.

Repetitive PCR fingerprinting of 24 strains of P. syringae pv. syringae isolated from different host/areas were compared with a standard strain ofPss from Greece (BPIC 242).Bacterial DNA was prepared with three known methods i.e. freeze-boil, whole colony boiling and directly from washed leaf surface. Initial result showed no purified genomic DNA extraction was necessary for rep-PCR analysis. On the other hand, Rep patherns of Pssshowed some correlation between host specialization and its habitant with genomic diversity. Strains isolated from stone fruits formed a distinct cluster from wheat and sugar beet strains and a similar pathern was found among all stone fruits strains in confined geographical areas. Therefore it was found the rep-PCR technique as a rapid, simple and producible method to identify and classify these important plant pathogens.

In order to investigate the possible presence and molecular features of Peach Latent Mosaic Viroid (PLMVd) in west Iran (Kurdistan Province), a total of 132 leaf samples from almond, apricot, nectarine, peach, plum, sour cherry, and sweet cherry were collected from orchards during the summer of 2016 and 2017. Reverse transcriptionpolymerase chain reaction amplified an expected ~350 base pair DNA fragment from 34 samples. The complete genome sequencing of 17 cloned isolates was determined. Sequence alignment of the new sequences showed 94. 3-100% nucleotide identity, and 79. 2-100% nucleotide identity with other previously reported PLMVd isolates. In phylogenetic analysis, isolated viroid variants from this study and 32 previously reported isolates were placed in two groups (I and II). All the isolated viroid variants in the present study were placed in group II-A (mosaic-inducing isolates), together with other isolates from Australia, China, India, Iran, Spain, Tunisia, and Turkey. The secondary structure of the Iranian variants revealed their unique structures as compared with previously reported isolates of the viroid. To our knowledge, this is the first report of PLMVd infection on apricot, sweet cherry, sour cherry, and nectarine in Iran.

In order to study molecular identification and genetic diversity of Prunus necrotic ringspot virus (PNRSV), 149 leaf samples from 37 orchards of pome and stone fruit trees of Kurdistan province were collected and tested by RT-PCR using a PNRSV-F3/PNRS-R3 specific primer pair. Results showed that 20. 8% of the samples were infected by PNRSV. In the next stage of the study, 13 isolates were selected based on the host and geographic region and their amplified fragments were ligated into the pTG19-T plasmid, transformed to E. coli DH5α , and sequenced. Phylogenetic analysis showed that PNRSV isolates formed three clades PV96, PV32, and PE5, and all new-sequences from Kurdistan (in this research) were categorized in PV96 phylogenetic clade, which is close to other Iranian isolates. The new isolates shared 99 ± 0. 002 identities together and 94/9 ± 0. 005 with other previously PNRSV reported isolates at the nucleotide level. Pairwise comparisons of sequences showed that isolates peach from Kamyaran (KH10), pear from Sanandaj (SZ93), and peach from Dehgolan (D7) had the highest nucleotide similarity (98%) with Iranian isolate nectarine (KX353935) whereas isolate pear from Sanandaj (SZ26) had the lowest nucleotide identity with isolate plum from Poland (DQ983499). The low dN/dS ratio in all populations of the virus showed that negative selection plays important role in PNRSV-CP evolution and recombination. There is no recombination event in this domain of PNRSV genome of these isolates.

Canker symptoms similar to those produced by Pseudomonas syringae pv. Syringae were observed on peach (Prunus persica) and nectarine (Prunus persicae var. nusipersica) trees in several fruit tree growing areas in Khorasan in 2011-2012.Symptomatic stem tissues were thoroughly washed under running tap water, surface disinfestated with sodium hypochlorite (2 min. in 0.5 %, ai, hypochlorite), washed in three changes of sterile distilled water (SDW) and the bark tissues were stripped-off and chopped in 1-2 ml of SDW with a sterile scalpel. Drops of the suspensions, following 10-20 min standing at room temperature, were streaked onto plates of sucrose nutrient agar (SNA) and the plates were incubated at 26-28oC. The predominant isolates recovered had cream to pinkish, circular, glistening, pasty and convex colonies with entire margins. The isolates did not produce fluorescent pigments on medium B of King. A number of isolates induced a hypersensitive (HR) -like reaction in geranium (Pelargonium ´ hortorum) and in tobacco (Nicotiana tabacum) 4-5 and 11 days after injection of somewhat turbid suspensions, respectively. The necrotic areas or spots formed on tobacco were surrounded by halos and tended to enlarge, albeit, slowly. DNA of a representative from each group of isolates, differentiated by their colony morphology on SNA, was extracted and the ITS region of the rDNA operon was amplified in PCR and sequenced. Based on the identity of the nucleotide sequence of this region with those deposited in GenBank, the two colony types that were proved to be pathogenic to peach and induced a Hr-like reaction in tobacco and geranium were found to belong to the yeast speciesCryptococcus adeliensis and C. magnus. Koch’s postulates were fulfilled with representative of both species on peach budlings (Borhaniet al.2012.11 th European Conference on Fungal Genetics, Philipps-University, Marburg, Germanyand Borhaniet al.2012.13 th International Congress on Yeasts, Univ. Wisconsin, Madison, USA).A number of isolates displayed characteristics distinct from those of the two Cryptococcus species described. Colonies of the present isolates were glistening, pasty, milky white in color and very low convex.Blast analysis of the ITS sequence of a representative (NCBI # JQ039905) of this group of isolates, which produced a Hr-like reaction in geranium but appeared to be avirulent on peach in greenhouse tests, showed 100% identity with those of Meyerozyma guilliermondi isolates present in GenBank. The fatty acid methyl ester (FAME) compositions of a representative isolate and a reference of strain Meyerozyma guilliermondi, CBS # 8417, were determined by gas chromatography. The similarity of the two isolates was verified further by the identity of the types and the percentages of fatty acids. C18: 1 was determined to be the predominant fatty acid (40% of the total fatty acid compositions) in both isolates. The role of this third group of yeast isolates, if any, in the stem canker complex, could not be established in the preliminary pathogenicity trials carried out in the present study and remains to be determined in the future. Induction of hypersensitive reaction on geranium may be considered as the potential of this yeast species in causing disease in one or more plant species.

Iran is a very rich country in fruit tree resources, and in terms of growing fruit trees in cold, subtropical, and tropical areas, Iran is one of the few places in the world that can cultivate most of the world's fruits. this study aims to investigate the flower and fruiting dynamics of some pome and stone fruit trees, including European pear (Espadona cultivar), two apple cultivars (Granny Smith and Starking), quince (Isfahan cultivar), two cultivars of nectarine (Shams and Moghan), sweet cherry (Takdaneh cultivar of Mashhad), peach (Alberta cultivar) and plum (California cultivar), in the Khorramdareh city of Zanjan province. The results obtained in the present study showed that all the studied species were able to grow and bear fruit in these areas, and can produce high-quality fruits (in terms of firmness, soluble solids, etc.). European Espadona pear cultivars were also able to produce high-quality fruits in this area of Khorramdareh city. The studied apple cultivars were also able to produce high-quality fruits in terms of morphological and physiological traits, Isfahan quince trees had better quality and yield in terms of fruit production than other stone fruits such as cherries, peaches, nectarines, and plums, However, the products of other stone fruit trees had good quality in terms of morphological and physiological traits. According to the data obtained from the flowering dynamics of different species, the present study evaluates the possibility of spring frosts.