Evaluation of some fungicides for the control of Fusarium dry rot of potato

Five fungicides, with active ingredients azoxystrobin, imazalil, thiabendazole, azoxystrobin + difenoconazole and fludioxonil + difenoconazole, were tested against two isolates of Fusarium solani and two isolates of F. oxysporum, causing potato dry rot in Mashhad region. PDA media amended with the fungicides significantly inhibited the mycelia growth of all Fusarium isolates incubated at ۲۵ °C for ۷ days; however only Imazalil and Thiabendazole completely stopped the mycelia growth of all fungal isolates even at their lower concentration (۴۰ and ۵ppm respectively). The mean penetration of F. solani FPO-۶۷ and F. oxysporum FPO-۳۹, the more virulent of the four isolates, after ۲۱ days of incubation at ۲۵-۲۷ °C indicated that imazalil and thiabendazole at concentrations of ۱.۵ and ۲/۱۰۰۰, completely inhibited the penetration of F. oxysporum FPO-۳۹ into potato tubers, but in the case of F. solani FPO-۶۷ all treatments (۱, ۱.۵ and ۲/۱۰۰۰) significantly reduced the development of dry rot compared to untreated control. In natural condition, tuber treatment with Imazalil and Thiabendazole (۲/۱۰۰۰), prior storage, reduced F. solani FPO-۶۷ development by ۶۸ and ۷۱.۶۹% respectively. According to the results, these fungicides could play a role in integrated pest management against tuber-borne fungal pathogens.

Keywords:

Azoxystrobin , Difenoconazole , Fludioxonil , F. oxysporum , F. solani , Imazalil , Mashhad , Thiabendazole