Pathogenicity of Fungal Agents Related to the Diseases of Conifers of Cupressaceae in Greenhouse Conditions

Conifers, a component of beauties of parks and landscapes, are infected with diverse pathogens, especially fungi. In this research, samples were collected from conifers displaying symptoms of disease in parks and landscapes of Rasht in Iran and for the isolation and identification of pathogenic fungi, pieces of infected tissues were placed in PDA and at the next stages in WA, PCA and SNA media and in total, 58 isolates were isolated andidentified based on morphological characters. These fungi belonged to Alternaria franseriae, Alternaria tenuissima, Curvularia pallescens, Fusarium sambucinum and Pestalotia sp. Afterward, pathogenicity test of these fungi was done on Chamaecyparis lawsoniana, Chamaecyparis lawsoniana 'Minima Aurea', Thuja sp., Juniperus horizontalis, Juniperus chinensis and Cupressus arizonica and to do so, a spore suspension was prepared with the concentration of 5 × 104 spores per ml distilled water and then, the studied plants were inoculated. Final assessments were carried out 10 days later to determine disease intensity. Results showed that A. franseriae on C. lawsoniana, A. tenuissima on C. lawsoniana 'Minima Aurea', C. pallescens on C. lawsoniana and J. chinensis, F. sambucinum on J. horizontalis and Pestalotia sp. on C. arizonica and C. lawsoniana 'Minima Aurea', were pathogenic. The most disease severity was caused by A. franseriae on C. lawsoniana and the least disease severity by Pestalotia sp. on C. lawsoniana 'Minima Aurea'. Among the studied plants, C. lawsoniana and C. lawsoniana 'Minima Aurea' showed the greatest sensitivity and the most resistance, respectively. Analysis of variance revealed significant differences in disease intensity of the studied fungi. The occurrence of A. franseriae, A. tenuissima and C. pallescens on conifers has been reported for the first time from Iran on conifers.