Disease incidence and favorable condition on disease severity is evaluated. W. carpophilus isolated of infected orchards. For fungus overwintering method in buildup were carried out bud washing by centrifuge and spot culturing on nutrient mediums. Evaluation of shot hole in different areas showed that cultivars response to this disease is fixed inside of a climate but it is differ in different areas to each other. Fungus germination optimum was indicated 95% at 15oC and its minimum 0.5% at 1oC in experimental conditions. Fungus overwintering were confirmed as hyphae and conidia inside of bud and as hyphae in twig spots. The result of study indicating climatic effective role that is dominant in area in disease incidence and severity.

Introduction: Shot hole disease of stone fruit trees resulted from Wilsonomyces carpophilus can weaken the trees and reduce the quantity and quality of the crops worldwide particularly in semi-arid regions. Coryneum blight or shot hole disease infects all the stone fruit trees including peach, nectarine, apricot, sour cherry, plum, cherry, and almond. One of the most important strategies to manage any plant disease is to use resistant cultivars.In this way, it is very important to have knowledge about the status of genetic diversity and to determine the relationship between isolates of the causal agent fungus. The main objective of the present research was to study the genetic diversity ofW. carpophilus in Khorasan Razavi province using the rep-PCR molecular fingerprinting method.Materials and Methods: Sampling was performed from peach, nectarine, plum, apricot and cherry orchards of Quchan, Torqabeh, Shandiz, Chenaran, Neishabur, Kalat, Torbat Heidarieh and Mashhad during spring and summer of 2012 and 2013. Mono-conidial isolates were recovered from infected leaves, fruits, and twigs of different parts of orchards. Infected collected leaves, twigs, and fruits were transferred to the laboratory. By using techniques of Klimesova and Prasil (1989) and Mehta (1998) from the cut parts between infected and healthy tissues of each isolate, cuts of 2-3 mm from leaf, fruit and twig were prepared by the scalpel. These pieces were surface sterilized with 1% sodium hypochlorite liquid about 1 to 3 minutes based on the thickness of tissue. Then, the samples were cultured on PDA, MEA, and WA media and incubated at 18, 20, and 25 °C. The isolated fungi were purified and identified. The research was performed on 20 fungal isolates collected from different stone fruit trees. Genomic DNA was amplified using BOX A1R, ERIC2, ERIC1R, REP2-I, and REP1R-I primers. Thirty-eight of 39 fragments amplified were polymorphic for 100 to 5000 base pairs.Similarity matrix between isolates was calculated based on Jacquard Coefficient and cluster analysis and construction of dendrogram were done based on UPGM using NTYSIS.PC 2.0 software.Results and discussion: From 39 amplified bands, 38 bands (97.5%) showed polymorphism. The molecular weight of amplified DNA fragments was between 100 to 5000 bp. Based on analysis of banding pattern of REP primer set, isolates of W. carpophilus were categorized into 12 groups at the 69% similarity level. The most genetic similarity of isolates (94%) was between AK (apricot of Kalat) and PK (peach of Kalat) and the least genetic similarity ofW. carpophilus isolates was between AQ (apricot of Quchan), AN (apricot of Neishabur), AC (apricot of Chenaran), PlM (plum of Mashhad), PM2 (peach of Mashhad number 2), and CC (cherry of Chenaran) with the other isolates. Based on the results of this study rep-PCR could separate isolates ofW.carpophilusvery well and also could separate similar isolates and hosts which have the close genetic relationship. Similar results were obtained by Edelet al. (1995) and Jedryczka et al. (1999). Edel et al. (1995) compared three different molecular methods for characterization ofFusarium oxysporum strains. The marker also separated isolates of Kalat and Chenaran geographically and to some extent isolates of plum in terms of hosting from the other isolates. Todaet al. (1999) in their study, about the investigation of genetic correlation among and within different isolates ofRhizoctonia solani by rep-PCR divided the 41 isolates into 7 groups which indicate considerable genetic diversity among isolates. Also, Karimiet al. (2010) in their study about the investigation of genetic diversity ofSclerotinia sclerotiorum at 64% similarity level, divided the isolates into 7 groups and separated most of the isolates geographically.Conclusion: The results obtained in this study indicated that rep-PCR is a practical, rapid, and accurate technique for separation ofW. carpophilus isolates. Considering the high genetic diversity observed in thepopulation of this fungus, making attempts to plant cultivars with high resistance and resistant genes can largely prevent the outbreaks and intensity of the pathogen. Therefore, further researches in this area can be placed in breeding, production and reproduction of cultivars with particular resistance programs against shot hole disease.The present research study is a prelude to solving problems related to this important disease.

To determine the specificity and host range of Wilsonomyces carpophilus isolates, some stone fruit seedlings (Prunus armeniaca, Prunus dulcis, Prunus reuteri, P. vulgaris, P. domestica, P. persica, P. avium and P. cerasus), pome fruits (Malus communis, Pyrus communis, Crataegus azarollus and Crataegus monogyna) as well as ornamental plants (Rosa persica, Rosa sp. and R. damascena) were selected for pathogenicity tests under greenhouse conditions. Five isolates from five different hosts (apricot, almond, plum, peach and sweet cherry) were taken for pathogenicity tests on ten leaf-seedlings under 20±2oC and relative humidity of more than 75%, using atomized 105 conidial suspensions. The results showed that all isolates caused disease on Prunus seedlings. No specificity was observed between isolates and hosts. Pale brown to black lesions were observed on some of the pear leaves and twigs, and as well on apple and hawthorn leaves after 4 days past of inoculation. Lesions did not expand or abscise and there was no sporodochium observed on leaves even after 20 days past, so that, pear, apple and hawthorn were not determined as important hosts of the fungus. In addition, symptoms were not observed on the ornamental plants and on whitethorn, raising the expectation that the fungus is limited to stone fruits. Appearance of disease symptoms on almond, plum, peach and nectarine, and on apricot twigs in orchards, infection of plum and apricot twigs in greenhouse and isolation of fungus from these are the first reports from Iran. To evaluate the relative resistance of nine peach cultivars to tree fungus isolates, as based on the number of lesions per 10 cm2 of leaf surfaces, tests were carried out under greenhouse conditions (20±2oC and relative humidity of more than 75%). The results indicated that there were significant differences among relative resistance of cultivars and among isolates' pathogenicity. Redtop, Springcrest and Early Elberta cultivars were resistant, whereas, Dixired cultivar was recorded as highly susceptible.

During a survey on shot hole disease of stone fruit in Razavi Khorasan Province in 2006-2007, the fungi Wilsonomyces, Ulocladium, Alternaria, Curvularia, Fusarium, Nigrospora, Drechslera, Penicillium, Stemphyliumand Cladosporium were isolated from infected leaves and twigs of Peach, Apricot, Almond, Cherry, Sour Cherry and Prune on PDA, MEA and WA media. The fungi which had more frequency in the isolations were purified and inoculated on leaves in laboratory andin situ. The results revealed that A. alternata (Fr.) Keissler, W. carpophilus (Lev.) Adaskaveg, Ogawa and Butler and Ulocladium atrum Preuss; were more important causal agents of shot hole respectively in Razavi Khorasan Province.

Sour cherry trees in Guilan Province are infected by at least two fungi that cause leaf spots and shot holes namely Wilsonomyces carpophilus and Pruniphilomyces circumscissus. In the late summer and early autumn of 2023, a leaf spot in the form of small purple-red to brown lesions about 1-3 mm in size was seen on the sour cherry trees in Sumaehsara County, Guilan Province, Iran. Mature conidiomata, acervuli, were formed frequently on the abaxial leaf surface at the center of each lesion, producing asexual conidia in white masses. Morphological and molecular studies showed that Blumeriella jaapii is associated with the sour cherry leaf spot disease. This is the first report on this fungus and the first attempt to sequence the ITS-nrDNA as the primary barcode of Blumeriella jaapii in Iran.