Aflatoxins are the most serious problem in production and export of pistachio in Iran . They are among the most toxic mycotoxins and are produced predominantly by Aspergillus flavus and A. parasiticus . Pistachio is susceptible to invasion by aflatoxicogenic Aspergillus species and subsequent production of aflatoxins, during preharvesting, processing, traortation or storage. Conventional methods for detection of these toxins in pistachio, are including different methods of chromatography such as TLC and HPLC, that are time consuming, labor-intensive and expensive. PCR methods are more rapid and objective for identification of aflatoxicogenic fungi. Equivalent genes for these fungi are aflatoxin biosynthesis genes that have already been cloned and their sequence are known. These genes are nearly identical in A. flavus and A. parasiticus and the same PCR system can be used for detection of both species. In this study, nuts sample were collected from pistachio orchards in Kerman , Rafsanjan and Isfahan . AFPA and PDA media were used to isolate Aspergillus species. Two hundred and fifty isolates were obtained and used for furthure study. These isolates belonged to Aspergillus , Fusarium , Rhizopus , Alternaria and Cladosporium species. Microscopic and macroscopic characters of Aspergillus species were observed on CYA, CY20S and MEA after one week. Out of 200 isolates, ten Aspergillus species were identified as, A. alliaceus , A. candidus , A. flavus , A. niger , A. niveus , A. ochraceus , A. parasiticus , A. tamari , A. terreus , A. unguis and A. wentii , that A. alliaceus, A. candidus, A. niveus, A. unguis and A. wentii , was reported for first time from Iran. Isolates No.
