FIELD INVESTIGATION AND SURVEY ON DISEASES OF GLADIOLUS (Gladiolus grandiflorus L.) IN SELECTED AREAS OF BANGLADESH

Abstract

Three experiments were conducted to investigate the diseases of gladiolus in Jashore, Dhaka and Manikganj districts of Bangladesh during February 2019 to May 2019. Eighteen villages from 4 Unions of Jhikorgacha Upazila of Jashore, two villages from Savar upazila of Dhaka and two villages from Singair upazila of Manikganj district were selected for investigation. The disease incidence and severity were recorded under natural epiphytic conditions. Seven diseases were identified from cultivated gladiolus in Bangladesh viz. leaf spot, leaf blight, stem rot, corm rot, flower rot, aster yellow and mosaic diseases. The identified causal organisms for leaf spot, leaf blight and flower rot disease are Curvularia trifolii, Botrytis gladiolorum and Curvularia lunata, respectively. However, stem rot and corm rot diseases are caused by Fusarium oxysporum f. sp. gladioli. Mycoplasma caused aster yellow and virus caused mosaic diseases of gladiolus were recorded in the field of Jashore. The incidence and severity of diseases varied significantly among the locations. In leaf spot disease, Incidence and severity varied significantly from 22% to 72.67% and 2.67 % to 15%, respectively. In case of leaf blight disease, the highest disease incidence and severity were recorded in Dhalipara, Jashore that were 77.33% and 11.67%, respectively. Severity of stem rot was observed highest in Nirbashkhola (11%) and the lowest in Baisha village (2.67%). Disease incidence was varied from 10.67% to 25.33% for corm rot disease. Incidence of flower rot disease varied significantly from 5.33% to 10%. In case of Aster yellow disease, the highest disease incidence (9.333%) was recorded in Mathuapara and Godkhali villages. The mosaic disease of gladiolus was found only in Sharifpur village of Jhikargacha union of Jashore. The disease incidence and disease severity were 3.33% and 20%, respectively. Farmer’s saved corms of gladiolus were collected from Dhaka, Manikganj and Jashore districts and health status was also investigated by modified blotter paper method in this study. Five fungi viz. Fusarium oxysporum, Aspergillus flavus, Aspergillus niger, Rhizopus stolonifer, Chaetomium sp. were isolated and identified from corm of gladiolus. Apart from this, a survey was carried out on the socio-economic status of gladiolus farmers and problem related gladiolus cultivation in Bangladesh.