Prevalence and integrated management of cotton aphid, Aphis gossypii Glover (Homoptera: Aphididae) were studied on four varieties of roof planted eggplant (Solanum melongena L.) Along the sixteen weeks study period highest incidence of aphids (1959.17.17±172.44/plant) on eggplant variety of Blackboy were recorded at 16 th week (last week of February, 2013) and the lowest incidence (12.83±8.68/plant) was recorded on the eggplant variety Singnath at 13 th week (first week of February, 2013). The treatment having combination of 2g Neem seed kernel extract (NSKE) + ½gm detergent+100ml water) was most effective followed by a treatment of 2g NSKE+100ml water and 1g NSKE+100ml water in reducing the rate of aphid infestation. Eggplant variety Green round showed comparatively higher resistance in all aspects (from leaf and fruit infestation) followed by variety Muktakeshi and Black boy.

This investigation was undertaken to evaluate some physico-chemical parameter of water of the trans-boundary Haora River in Brahmanbaria during October 2018 to September 2019 from three different sites. The study revealed that air temperature at three different sites ranged 13 – 38 °C while the water temperature was 11 – 32 °C. Transparency of water varied from 18 – 55 cm Secchi depth and became more turbid during monsoon. The average values of pH and dissolved oxygen (DO) both in sites and seasons were within the standard limits for aquatic organisms. Total dissolved solids (TDS) were found between 77 and 352 mg/L and varied greatly in seasons. Electric conductivity (EC) was ranged 135 to 650 μS/cm. On the other hand, maximum and minimum hardness of water were recorded as 322 mg/L and 118 mg/L respectively and become lowest in monsoon. The rainy season bear high torrential water which brought huge amount of different types of garbage through the water flow from the Indian part. Most of the garbage are of floating and submerged type as plastic containers, bottles, polybags, cans, etc along with natural debris. During the study period highest (172 kg) and lowest (113 kg) plastic garbage were collected in May and July respectively. This foreign garbage may impair the normal healthiness of the river ecology. Bangladesh J. Zool. 49(1): 137-146, 2021

Although some water quality parameters of DND canal were found to be suitable for aquaculture but it was organically polluted. Further investigation on the heavy metal pollution is necessary before using the water and crops produced from DND canal for anthropological use.

The investigation was conducted on the present situation of fish biodiversity and abundance of fish fauna at two different points of Madhumati River at Mohammadpur upazilla under Magura district from October 2018 to September 2019. A total of 83 species of fresh water fish species were recorded belonging to 58 genera of 28 families under 11 orders. Cypriniformes was recorded as the dominant order comprising 26 species constituting 31% of the total. According to IUCN 59% of fish species were Least Concern, 12% were Vulnerable, 11% were Endangered, 9% were Near Threatened, 1% of each were Data Deficient and Critically Endangered locally, and 7% Exotic fish species were also enlisted. Annual value of Shannon diversity index (H) was 1.974 and Sipmson diversity index (λ) was 0.272 which indicate highest diversity of fish was in March. Annual Margalef’s richness index (D) was 6.654 and Pielou’s evenness index (E) was 0.447 denote highest richness was in November and evenness was in March. The river was found to have moderate type of diversity in terms fish species composition. Bangladesh J. Zool. 49(1): 19-34, 2021

Present investigation was conducted to assess the physicochemical characteristics of water and its suitability for fish production at Dhaka-Narayanganj-Demra (DND) dam wetlands. Data were collected at eight points of the study area between March 2014and February 2015on temperature, transparency, pH, dissolved oxygen (DO) and free carbon dioxide (CO2) in the water. The average maximum water temperature, transparency, pH, DO, free CO2, hardness were recorded as34.6±0.4°C, 40.3±0.8cm, 7.9±0.06, 7.6±0.4 mgL-1,85.6±6.6 mgL-1 and 491.2±76mgL-1while minimum average were found as26.3±1.0°C,7.1±0.2 cm, 7.4±0.05, 5.9±0.3 mgL-1, 11.9±0.8 mgL-1 and 87.6±11.3 mgL-1respectively.All the water parameters were found in favourable condition for optimum freshwater fish production with some modification. This study can be the baseline data toward fresh fish supply and production prospect in the Dhaka city at wetland of the DND canal area. Bangladesh J. Zool. 48(1): 93-103, 2020