جستجوی مقالات مرتبط با کلیدواژه "شانکر سیتوسپورایی" در نشریات گروه "گیاهپزشکی"

In an assessment for determination the role of nitrogen and potassium on incidence and development of Cytospora spp. associated with apple trees، 52 Golden delicious gardens randomized selected and sampled from leaves and soils (0-30، 30-60 cm deep) in Junuary. Sample compound prepaired in laboratoary، macro and micro elements based on Wet Digestion Method analyzed. The results were subjected to analyzed and required discussious، based on Deviation from Optimum Percentage (DOP) method in infected gardens to recent index concentration in non infected ones. Potassium deficiency and high level of nitrogen were observed in infected gardens. Research on the role of these elements were performed on the fungus. This part of invastigation was done on seedlings of the two-years-old Golden Delicious apple cultivars، in factorial randomized block design with two factors (16 treatments) and four replications. After 6 weeks، seedlings were inoculated with high virulence isolate. In most treatments callus tissue was formed around the site of inoculation in late spring and along summer. But the invasion of health tissues began in the fall، and cankers caused seedlings were dead. The results showed that only tissue callus was formed around the replications: N0K0، N0K115، N0K230، N0K345، N105K230. N105K345، while none of the treatmens were dried. In treatments K0N105، K0N210، N105K115، N210K230، N210K345، N315K345، 25% of replications were dried. In treatments K0N345، N210K115، N315K230، % 50 repetitions، while in treatment N315K115، % 100 repetitions were dried. It''s characterized by increasing potassium and reduce of nitrogen in treatments، percentage of deaths variable and it''s increasing. This results were the same results obtained from health and infected apple trees leaves and soils.

Cytospora dieback and canker disease is one of prevalent disease of walnut trees in Iran caused by several species of Cytospora genus. The aim of this study was to determination of virulence degree in 58 isolates of dominant species، Cytospora chrysosperma. isolates from 12 provinces of Iran; Hamedan، Kurdistan، Kermanshah، Ilam، West Azarbaijan، Zanjan، Markazi، Lorestan، Chaharmahal va Bakhtiari، Isfahan، Kohgilouye va Boyerahmad and Fars were inoculated on three-year old seedlings and lesion area have been recorded 30 days after inoculation. Furthermore، Pathogenicity survey on detached twigs carried out in laboratory situation to check accuracy of pathogenicity determination. Based on these results، there was noticeable variation in virulence degree of tested isolates. However، most of isolates didn’t show any pathogenicity. Indeed، 34% and 24% of isolates didn’t shown significant difference with control in pathogenicity test on seedlings and detached twigs، respectively. Also، there was week but significant (23%) correlation between two evaluation methods. Collectively، it seems that evaluation of virulence or resistance degree would not be reliable via the detached twigs technique.

In the course of a research project during 2008-09, diseases of mulberry shoots in Izadshahr (Mazandaran), Astaneh Ashrafieh (Guilan) were investigated. The results showed that phloeospora leaf-spot caused by Phloeospora maculans on Morus species is a widespread disease in the above mentioned cities. Also, diatrype die-back on white mulberry, caused by Diatrype stigma, is a rather important disease in Astaneh Ashrafieh. A full account of the symptoms of the diseases and also details of their causal agents are presented here. Malberry is a new host for Cytospora cincta and Diatrype stigma in Iran. Specimens of the two diseases are preserved under IRAN 14695F and IRAN 14692F in the Herbarium of Iran (IRAN) at the junior author's address.