Fungicide treatments for the control of storage rots of seed potatoes

Five fungicides were compared with a standard mercuric fungicide for the control of gangrene and Fusarium dry rot of seed potatoes. Seed tubers were artificially wounded and inoculated with Phoma exigua var. foveata and/or Fusarium trichothecioides before dipping in suspensions of the test fungicides. All of the six fungicides tested on tubers infected with P. exigua var. foveata reduced gangrene significantly. Of the three most effective materials, viz, thiabendazole, imazalil and prochloraz, imazalil proved to be the best for the control of gangrene. Combining imazalil with either thiabendazole or prochloraz did not improve control. Of the fungicides tested, thiabendazole gave the best control of dry rot, caused by F. trichothecioides. However, control was improved by combining this fungicide with prochloraz and imazalil.