Potato tuber moth, Phthorimaea operculella, is one of the important pests of potato spesially in stored condition. Adverse effects of pesticides on human health and environment in addition with developing resistance, attracted reserchers to develop new safe control methods. In these study effects of some isolates of Beauveria bassiana and Metarhizium anisopliae collected from different regions of East Azarbaijan and Tehran provience in addition with InsectoSec^® formulation of Diatomaceous earth was evaluated against PTM larvae. Results revealed that, CS1 isolate of B. bassiana with LC₅₀ value of 6519 and DE isolate with LC₅₀ value of 89026 conidia/ml were the most and least effective isolates. LC₅₀ value of diatomaceous earth calculated as 164 ppm. The time needs for emergence of poisoning sysmptomes and mortality wasn’t same in all isolates, CS1 isolate showed the least LT₅₀ equals 1.68 days in first concentration and 20.16 days in second one. The LT₅₀ value of diatomaceous earth calculated as 4.76 days in 500ppm concentration. According to te the results of this research SC1 isolate of M. anisopliae and SA2 isolate of B. bassiana were more virulent. Also diatomaceous earth formulation had acceptable control on PTM larva. It seems these isolates and diatomaceous earth, could be used as a management tool for controlling potato tuber moth.