SWEET POTATO TUBER ROT DISEASE IN THE PHILIPPINES

Abstract

Tuber rot or Java black rot, caused by Diplodia theobromae (Pat.) Nowell is the most prevalent storage disease of sweet potato. Affected tubers become dry, hard and coal-black in color. Isolations made from stored sweet potato revealed a high incidence (69%) of D. theobromae alone and in combination with other fungi. The occurrence of Aspergillus, Rhizopus and Fusarium in tubers was limited. D. theobromae was artificially inoculated to healthy tubers from field-planted sweet potato accessions. BNAS-51 variety was used as check throughout the experiment. Preliminary results indicate that 78 cultivars were resistant, 13 were moderately resistant and 78 were susceptible to tuber rot.