Abstract
The existing market situation of seeds and seedlings of fruit species and management strategies of nursery diseases of seedlings of fruit species in the country is in a stage to be upgraded for successful fruit production to meet the national demand. This includes plant propagation and nursery management - a vital link in the production of quality planting material (QPM). Experiments were carried out during the period of 2005-08 to study the status of seed and seedlings trade of different fruit species with in the country, prevalence of seed borne fungi of selected fruit species, occurrence of diseases on seedlings of selected fruit species, effect of weather parameters on the incidence of seedling diseases of selected fruits in different major growing areas of Bangladesh with developing a model of environment friendly disease management tool of selected fruit species. The nation wide survey in 260 upzilla under 54 districts of Bangladesh revealed that seeds of more than 20 fruit species traded in 531 seed stores and a total 16288.10 kg seeds were sold out in the surveyed stores that cost around Tk. 35.90 million in 2005-06. The study of seedling trade in 586 nurseries located at 260 Upazila of 52 districts of Bangladesh revealed 17million seedlings of more then 20 fruit species were sold out in the surveyed nurseries and of total price of Taka 363 million. A specialized software namely "Fruit seed & seedling trade" (FSST) have been developed to analyze the survey data and to interpret the information instantly. Seed health study of seven fruit species showed around 23% infection of seeds by fungi. Six species of fungi were detected from the seeds viz. on Guava Fusarium oxysporum and Colletotrichum gloeosporioides; on Jackfruit Aspergillus flavus, Aspergillus niger, Chaetomium sp. and Fusarium oxysporum; on Jamun Aspergillus flavus, Aspergillus niger, and Pestalotiopsis psidii; on Jujube Fusarium oxysporum; on lemon, Aspergillus flavus and Fusaruim oxysporum; on Litchi Aspergillus flavus and Fusarium oxysporum; on Mango, Aspergillus flavus, Aspergillus niger, Colletotrichum gloeosporioides and Fusarium oxysporum. This is the first time report in the country except jamun and jackfruit. Thus 14 out of 18 fungi recorded on the seeds of fruit species appear to be new record in Bangladesh. Significant plant pathogens viz. Colletotrichum gloeosporioides, Gloeosporium, Pestalotia psidii, Alternaria alternata Erysiphe, Sphaceloma fawcetti, Phytophthora spp. Lasiodiplodia theobromae Oidium mangiferae, Fusarium oxysporum and Cephaleuros virescens were detected and identified. Incidence and severity of important seedling diseases of selected fruit species viz. anthracnose of guava; leaf spot of jackfruit; scab of lemon; anthracnose, leaf spot and powdery mildew of litchi; anthracnose, red rust, powdery mildew and leaf spot of mango were studied and significant variations were observed that depends on weather factors. Correlation and linear regression analysis on occurrence of seedling diseases with temperature, rain fall and relative humidity revealed that all the diseases were influenced by the epidemiological factors and varied according to host patho- system. Comparative effectiveness of BAU-biofungicide either alone or in combination with two fungicides viz. Cupravit and Bavistin were evaluated on different seedling diseases of five fruit species viz. jackfruit, jamun, jujube, lemon and mango in the nursery. Among the treatments applied, Trichoderma harzianum based BAU- Biofungicide showed excellent result in controlling leaf spot diseases. Use of Cupravit and Bavistin either alone or in combination with BAU-Biofungicide also reduced the incidence and severity of diseases of seedling. However, BAU-Biofungicide, as an alternate to chemicals can successfully be used.