Evaluation of some fungicides against symbiotic fungus Ambrosiella hartigii associated with Anisandrus dispar Fabricius and Xylosandrus germanus Blandford (Coleoptera: Curculionidae: Scolytinae)

In this study, the efficacy of seven fungicides (azoxystrobin, captan, iprodione, imazalil, prochloraz, thiram and cyprodinil+fludioxonil) on two isolates (TR-202 and TR-205) of Ambrosiella hartigii was evaluated at in vitro . The fungicides at five concentrations (0.25x, 0.5x, 1.0x, 2.0x and 4.0x; where x is the field rate recommended by the manufacturer) were used in this study. Results showed that all doses of the fungicides significantly inhibited the   mycelial growth of these isolates compared to the control (P<0.05). Especially, captan, imazalil, prochloraz and cyprodinil+fludioxonil completely inhibited the mycelial growth of A. hartigii isolates even at the lowest dose. In addition, thiram, iprodione and azoxystrobin depending on increased doses reduced the mycelial growth of these isolates at rates between 75–100%, 65-100% and   52-85%, respectively. The doses that caused 50% reduction (ED 50 ), minimum inhibition concentration (MIC), and minimum fungicidal concentration (MFC) values indicated that imazalil, prochloraz and cyprodinil+fludioxonil were more effective to the fungus compared to other fungicides. Moreover, there were no differences between two isolates with regard to ED 50 , MIC and MFC values of the fungicides.