Determination of sensitivty to some fungicides on Penicillium digitatum isolates in mersin citrus packing house

In this study the population of Penicilium spp. was assessed in the packinghouses of Mersin province and an obtained 36 P. digitatum isolates sensitivity to fludioxonil, imazalil and thibendazole was examined. In the packinghouses the highest population rate of Penicillium was detected at the fruit entrance areas and Penicillium digitatum was found as the common variety. In vitro, fludioxonil was the most efficient fungicide which inhibited the mycelial development of P. digitatum isolate below 1 ppm. In vitro efficiency evaluations has revealed two imazalil resistant and seven thiabendazole resistant P. digitatum isolates. On Valencia orange fruit, imazalil and thiabendazole restrained the fungus development at similar rates but the effectiveness of fludioxonil was dramatically low. With respect to fruit decaying, fungicides were more efficient on sensitive P. digitatum isolates compared to the resistant ones. Sensitive P. digitatum isolate hasn't developed resistance to imazalil and thiabendazole however, during the second transmission fludioxonil resitance occured. These results suggest that fungicide combinations may be an important practise for preventing the resitance development in packinghouses.