OCCURRENCE OF DIFFERENT DISEASES ASSOCIATED WITH GERBERA (GERBERA JAMESONII) IN DHAKA DIVISION

Abstract

The study was conducted to survey and identification of pathogenic diseases of gerbera plant in and around Dhaka and isolation of associated causal organism and confimation their pathogenicity during the period of April to October 2019, in the central laboratory of the Department of Plant Pathology, Sher-e-Bangla Agricultural University, Dhaka1207.

For survey total nine sites were visited of Agargaon, Savar, Gazipur and Narayanganj. Based on symptomological study fungal diseases such as Alternaria leaf spot (Alternaria alternata), Cercospora leaf spot (Cercospora sp.), Anthracnose (Colletotrichum capsici.), Blight (Curvularia geniculata), Sclerotinia wilt (Sclerotinia sclerotiorum), Gray mold (Botrytis sp.), Powdery mildew (Erysiphe sp.), Stem rot (Fusarium oxysporum.) and the viral diseases such as Mosaic (Mosaic virus), Leaf curl (Leaf curl virus) were identified. Among all identified diseases, Alternaria leaf spot showed the highest disease incidence (66.67%, Gazipur) and Gray mold showed lowest disease incidence (5.56%, Narayanganj). The reduction rate of plant height due to Alternaria leaf spot, Cercospora leaf spot, Anthracnose, Blight, Sclerotinia wilt, Gray mold, Powdery mildew, Stem rot, Mosaic and Leaf curl disease were 28.42%, 28.1%, 12.69%, 12.47%, 30.67%, 28.36%, 28.08%, 19.14%, 12.89% and 22.06% respectively. Reduction rate of other plant part due to Alternaria leaf spot (leaf length 42.62%, leaf width 26.79%), Cercospora leaf spot (leaf length 15.27%, leaf width 15.69%), Anthracnose (stem length 10.94%), Blight (leaf length 22%, leaf width 33.33%), Sclerotinia wilt (stem length 34.22%), Gray mold (flower size 42.86%), Powdery mildew (leaf length 19.17%, leaf width 18.75%), Stem rot (leaf length 17.42%, leaf width 17.65%, flower stalk length 44.78%), Mosaic (leaf length 24.43%, leaf width 34.78%) and leaf curl (leaf length 63.08%, leaf width 60.47%) were recorded. Following Koch’s prostulate, pathogenicity test of Curvularia geniculata and Erysphe sp. were done on healthy gerbera plants. Inoculated plant showed symptoms of Blight disease and Powdery mildew disease after 9 and 6 days inoculation respectively. Whereas controlled plant showed no symptoms of diseases. That confirmed the pathogenicity of Curvularia geniculata and Erysiphe sp.