Abdullahil Baki Bhuiyan

Garo people are tribal communities who live in the middle northern part of Bangladesh from time immemorial. The purpose of the research was to identify the reasons, outline, and impact on the relocation of Garo people in the city areas in Bangladesh. Primary data were collected from face-to-face contact through an interview schedule. The findings indicate that poverty, lack of production, unemployment, and security were the main push factors where urban job opportunity, urban life style and social security were pull factors for garo migration. Pattern analysis showed that 69 percent of respondents migrate to the city without a plan. Large farm and family size discourged the unplanned migarion where deteriorate social security influence garo people for unplanned migration. Study also revealed that garo people access to better income, health facility, transportation have increased. In contrast, the involvement of agricultureal activity greatly reduced. Moreover, migrated family maintain their daily requirement for food by purchasing market. Government should take policy for improving the security, income opportunity, and infrastructure for discouraging the unplanned migration from village to town.

Dragon fruit (Hylocereus polyrhizus) is an economically promising fruit in Bangladesh. The cultivation of dragon fruit has increased fourfold within a decade due to its popularity. Recently, a new disease known as stem canker was reported in some plantations of dragon fruit in Bangladesh, which forced some farmers to abandon their cultivation. This study aimed to explore the morphological, molecular, and cultural characteristics as well as host range of the causal agent associated with this destructive disease. Morphologically similar eight fungal isolates were recovered from eight canker symptomatic dragon fruit stems. Among them, two isolates (namely BU‐DLa 01 and BU‐DLa 02) were used for a detailed study. Morphological parameters and phylogeny of sequence data of internal transcribed spacer (ITS1, 5.8S rRNA, and ITS2), β‐tubulin, and translation elongation factor 1‐α identified the isolates as Lasiodiplodia theobromae. The cultural features were studied hinged on the growth of the two isolates on various media, temperature, and pH. Though the mycelial growth of the fungi was supported by all the media tested, potato dextrose agar was the most suitable one for both isolates. The fungi thrived well at a temperature of 25–35°C and 5.5–6.5 pH. Inoculation trials of dragon fruit stem ascertained Koch's postulate. In host range test, the isolates were found pathogenic toward mango, guava, banana, and the fruits of dragon fruit. These data will contribute not only to understanding the biology of L. theobromae as a newly recognized pathogen of H. polyrhizus but also will help in designing a proper management package against this pathogen.

Bangladesh is rich in wetland biodiversity with aquatic plants, fishes, and birds. Mohanganj Upazila is known as the capital of lower Bangladesh. The present study focuses on the changes of land use and land cover (LULC) with a diversity of species that are being least concerned (LC), vulnerable (VU), and endangered (EN). Over the last two decades, the wetland species of Mohanganj were gradually declined. Our results showed that 19 fish, 4 aquatic plants, and 7 bird species were LC in 2015. Among the fish and aquatic plant species, 6 fish species (Wallago attu, Ompok pabda, Channa punctate, Chitala chitala, Salmostoma phulo, and Corica soborna) and 2 aquatic plant species (Nymphaea nouchali and Nymphaea lotus) were VU during the dry and rainy season of 2017 and 2019, respectively. In the dry season of 2019, 4 fish species (W. attu, O. pabda, C. punctate, and Ch. chitala), 2 aquatic plant species (N. nouchali and N. lotus), and 7 bird species (Anas platyrhynchos, Ardeola grayii, Gyps bengalensis, Alcedo atthis, Phalacrocorax fuscicollis, Porphyrio porphyria, and Larus ridibundus) were EN. Among the species, W. attu, N. nouchaii, G. bengalensis, P. porphyria, and L. ridibundus were extremely endangered categories. Changes in LULC, the establishment of settlements for the increasing population, indiscriminate use of pesticides, environmental pollutions, and climate change are the potential reasons for declining trends of wetland biodiversity. Stern actions on land use policy, expansion of organic agriculture, bioremediation of industrial effluents, and adoption of sustainable environmental policies should be taken by the Government of Bangladesh for immediate conservation of wetland biodiversity.

Coconut (Cocos nucifera L.) is one of the most important fruit trees in Bangladesh. This tree is susceptible to various pathogens. Among them, a fungus was consistently isolated from gray leaf spot symptom in coconut. This study aimed to isolate, characterize, and find the management strategies of the causal fungus of gray leaf spot disease in coconut. Both morphological and molecular characters identified the pathogen as Pestalotiopsis sp. for the first time in Bangladesh. Artificial inoculation of this fungus showed symptoms similar to those previously observed in the field. Cross‐inoculation test suggests that Pestalotiopsis sp. has a wide host range. The infection process of Pestalotiopsis sp. started at 2 h after inoculation (hai) with the formation of germ tube followed by the formation of infection hyphae, which penetrated directly into the host at 6 hai. Gray leaf spot symptom was developed at 120 hai. Numerous conidia developed from the acervuli at 168 hai. These conidia acted as the source of inocula for secondary infection. The optimum temperature for the growth of Pestalotiopsis sp. was 25°C, however, the growth of Pestalotiopsis sp. ceased at 15°C and 35°C. This pathogen was completely inhibited by Autostin 50 WDG (carbendazim) at 100 ppm. Trichoderma viride (Pb‐7) was found as the potential biocontrol agent against Pestalotiopsis sp. These findings could contribute to describing the disease cycle and epidemiology of Pestalotiopsis sp. that would ultimately require to undertake effective control measures against this pathogen.

The outbreak of wheat blast ( Pyricularia oryzae , syn. Magnaporthe oryzae ) in Bangladesh and India in recent times is a cause of grave concern for future wheat production in South Asian countries. In this review, we focus on the origin and pathology of P . oryzae and its current status and impact on trade of wheat in South Asia. We also consider future directions for efficient detection, monitoring, forecasting, and managing this destructive disease. Proper detection and monitoring are essential for imposing disease management strategies. Cutting‐edge tools such as geospatial modelling and remote sensing technologies based on field observation will be pivotal to efficiently contain and manage the disease. Strong quarantine regulations too are critical in preventing the pathogen movement and are also discussed within. Complementary approaches, such as the induction of systemic resistance by applying plant growth‐promoting rhizobacteria or probiotic bacteria, are also considered here. This review provides a comprehensive summary on the status of wheat blast in South‐East Asia and will provide an important resource for wheat blast research in the affected areas.

Dragon fruit (Hylocereus polyrhizus) is a newly introduced, and a promising fruit crop in Bangladesh, which has gained considerable interests due to fruits appealing qualities and characteristics. Recently, a stem canker, a new disease of dragon fruit was observed in 30% of plants at different locations of Bangladesh. Initially, symptoms appeared as small brown lesions, which gradually increased in size. Ultimately, several coalesced lesions gave a stem canker symptom (Fig. 1). Isolation of fungi was carried out by the standard isolation procedure (Rodriguez-Galvez et al., 2017). Infected stem samples were surface sterilized in 2% NaOCl for 1 minute followed by 70% ethanol for 5 minutes. Small pieces (2 mm × 2 mm) from the margin of the necrotic lesion were cut and placed on half strength potato dextrose agar (PDA) medium, and incubated for 7 days at 25 °C. Single-spore isolates (BU-DLa 01 and BU-DLa 02) produced cottony white fluffy colonies on PDA covering the plate within 3-4 days (Fig. 1). Mycelial gr...