طی سال های ۱۳۸۵ و ۱۳۸۶ بیماری پوسیدگی ریشه و طوقه فلفل در استان آذربایجان غربی مورد مطالعه قرار گرفت .مزارع فلفل در شهرستان های ارومیه، مهاباد، میاندوآب، اشنویه و پیرانشهر در ماه های مرداد و شهریور سال های مذکور بازرسی شدند .از گیاهان مشکوک به آلودگی و خاک پای بوته های آلوده، نمونه برداری انجام و نمونه ها در اسرع وقت به آزمایشگاه منتقل شدند .به منظور جداسازی عوامل قارچی بیماری زا، از محیط های کشت PDA اسیدی، PCA و CMA و برای جداسازی عوامل شبه قارچی، از روش طعمه گذاری در خاک های آلوده استفاده گردید .سپس محیط های کشت انتخابی برای تشخیص جدایه ها در سطح گونه به کار برده شد .از بوته های بیمار و خاک های آلوده در مجموع ۸۲ جدایه، جداسازی و مورد بررسی تاکسونومیکی قرار گرفت .گونه هایPhytophthora capsici ،Pythium aphanidermatum ،Rhizoctonia solani ، Fusarium oxysporum ،F. solani ،F. chlamydosporum ، F. sambucinum و Verticillium dahliae شناسایی شدند .مطالعه بیماری زایی ۳۴ جدایه منتخب در شرایط گلخانه بر روی دو رقم فلفل) رقم دلمه ای و رقم محلی
.Pepper root and crown rot were investigated during ۲۰۰۶-۲۰۰۷ in West Azerbaijan province. Pepper fields were checked in Orumieh, Mahabad, Miandoab, Oshnavieh and Piranshahr in August and September. Infected plants with their soil were sampled and transferred to the laboratory immediately. In order to isolate of fungal agents, acidic PDA, PCA and CMA cultures were used and for pseudo-fungal agents, baiting method was applied in infected soils. Then, isolates were identified at species level using selective culture media. Eighty two isolates were taken from the infected plants and soils and were subjected to a taxonomic study. These isolates were related to Phytophthora capsici, Pythium aphanidermatum , Rhizoctonia solani, Fusarium oxysporum, F. solani, F. clamidosporum, F. sambucinum and Verticillium dahliae. Patogenicity test was carried out at greenhouse on ۳۴ selected isolates on two pepper cultivars (bell and native cultivars) in West - Azerbaijan, and percentage of the infected plants was calculated after a definite time from inoculation in depending on fungi species. Among the selected isolates, one isolate from F. sambusinum and another one from F. chlamydosporum had no pathogenicity effect on bell pepper, while four isolates from Rhizoctonia solani, one from Verticillium dahliae and another one from Pythium aphanidermatum had a higher pathogenicity effect. The rest were placed between these two groups. Three isolates from F. chlamydosporum and two from F. sambucinum had no pathogenicity on native cultivar, while two isolates of Rhizoctonia solani had the highest pathogenicity, and the rest were between these mentioned groups. It is noted that pathogenicity of F. solani on the native cultivar was very low. According to Koch rules, pathogens were isolated again from infected plants
Pepper root and crown rot
pathogenicity test
isolation and identification of fungal and pseudo-fungal agents.