Infectivity And In Vitro Production Of Sweet Potato Scab Fungus (Sphaceloma Batatas Saw.) Inoculum

Rodolfo  A. Paningbatan,

Infectivity And In Vitro Production Of Sweet Potato Scab Fungus (Sphaceloma Batatas Saw.) Inoculum

Abstract:

Sweet potato stem agar and exposure to continuous darkness supported the most abundant conidial production of Sphaceloma batatas. Saw. Sweet potato stem agar produced 19 times more conidia than sweet potato tuber agar and almost 3 times more conidia than potato dextrose agar. Sporulation in carrot agar peaked at 12-15 days after seeding and harvestable conidia generally declined after 18 days of incubation. Multipoint seeding of agar slants hastened sporulation and increased conidial production by almost 6 times compared to single-point seeding. Inf ectivity of conidia decreased with age of agar culture probably due to the drastic decline in conidial viability with age. Conidia from I-week old agar cultures were most infective on sweet potato internodes and leaves.

References:

LAO, F.O. 1978. Culture, morphology and pathogenicity of Sphaceloma batatas Saw. Unpublished M.S. Thesis, UPLB, College, Laguna, Philippines. 105 р.
LAO, F.O. and DIVINAGRACIA, G.G. 1979. Culture of the sweet potato scab fungus, Sphaceloma batatas Saw. Ann. Trop. Res. 1:1-13.
MEW, I.C., WANG, T.C. and MEW, T.W. 1975. Inoculum production and evaluation of mungbean varieties for resistance to Cercospora canescens. Plant Dis. Reptr. 59:397-401.
PANINGBATAN, R.A. 1980. Culture, morphology and pathogenic varia-tion of Cercospora species attacking peanut (Arachis hypogaea L). Unpublished M.S. Thesis, UPLB, College, Laguna, Philippines.
PANINGBATAN, R.A. and ILAG, L.L. 1981. Sporulation in vitro of Cercosporidium personatum (Berk and Curt.) Deighton and Cercospora arachidicola Hori from peanut. Phil. Phytopath. 17:21-29.
PUA, A.R. and ILAG, L.C. 1980. Growth and sporulation of Pseudocer-cospora psophocarpi (Yen) Deighton at different media, temperature and pH. Phil. Phytopath. 16:45-52.
TUITE, J. 1969. Plant Pathological Methods: Fungi and Bacteria. Burgess Publishing Co., Minneapolis, Minnesota, U.S.A. 239 p.
WINSTON, J.R. 1923. Citrus scab. Its cause and control. USDA Bull. No. 1118. 39 р.