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This research intends to design, assemble and evaluate the performance of an eco-friendly solar light trap to reduce the insect population in rice fields as well as to minimize the use of harmful chemical pesticides. An AutoCAD drawing tool 2016 was used to sketch the design of solar light trap. The main component of this light trap was bulb, solar panel and battery. Design of solar panel and battery was done considering by 5W LED bulb. A total of five bulbs with different colors were selected to test the insect’s reaction by visible light. Study indicated that ultra violet-blue bulb showed the best performance compare to others based on the high percentage of insect trap (31.22%). A 20-watt solar panel and two 4.5 ah batteries of 6 volts were used to operate the solar light trap. The current, voltage, solar intensity was recorded to check overall performance of solar panel. The solar panel generated more power in April than May due to higher solar radiation in the study area. Study suggested that only 4.26 sunshine hours were required to full charge the battery. The solar light trap was operated 5.5 hour in night which was sufficient to reduce the insects in rice field. Moreover, the light sensor was showed 100% functional for ON/OFF purposes. The dominant insects like yellow stem borer (YSB), green leafhopper (GLH) were mostly observed. The average largest numbers of YSB and GLH were 900 and 600 respectively. In conclusion, the solar light trap is eco-friendly, low cost, easy and self-sufficient in term of solar energy. Finally, the newly developed light trap could be helpful for manufactures, decision makers, and engineering community as well as farmers as a best tool to protect nature in comparison to other pesticide using practices.

The brown planthopper, Nilaparvata lugens (Stål), caused severe yield losses in rice production in many Asian countries. Chemical control is the key component of the integrated pest management tool to control rice brown planthopper (BPH). However, reduced toxicity of insecticides against this pest has been reported. We investigated the BPH mortality rate and the evolution of insecticide resistance in BPH collected from Bangladesh to commonly used insecticides by the rice-stem dipping method. Both the BPH laboratory strain and field populations were used in this study. The mortality rate of the Gazipur field population ranges from 15% to 80%, after exposure to imidacloprid in different concentrations. The highest mortality was found in response to dinotefuran followed by chlorpyrifos and etofenprox. The mortality rate increased after the time of exposure in relation to the increased concentrations of the insecticides. Additionally, the selected BPH strain shows a higher level of resistance to imidacloprid (resistance ratio = 179.45-fold), while other field populations show low to moderate levels of resistance. Increased detoxification enzyme activity, cytochrome P450 monooxygenase, was found in imidacloprid-resistant BPH. This study provides important information regarding the reduced toxicities of frequently used insecticides to control BPH.

The bacterial community living in the insect gut may play an important role in nutrition, immunity and protection, detoxification of toxins, and inter- and intra-specific communication. Rice leaffolder Cnaphalocrocis medinalis (Guenee) (Lepidoptera: Crambidae) is a notorious pest in rice, and the diversity of the gut bacteria of C. medinalis across life stages are not well understood. Here, the diversity and abundance of the gut bacterial community in C. medinalis through life stages were investigated using Illumina Miseq technology. A total of 22 bacterial phyla, 42 classes, 100 orders, 179 families, 350 genera and 395 species were identified across the different life stages of C. medinalis. Proteobacteria and Firmicutes phyla were the dominant bacterial taxa. Members of the genera Enterococcus, unclassified Enterobacteriaceae, Wolbachia, Acinetobacter, Stenotrophomonas, Microbacterium, Bacillus, Corynebacterium, Lampropedia, and Sphingobacterium were found at all life stages. Enterococcus and unclassified Enterobacteriaceae occupied higher relative abundance among bacteria community in the 2nd to 5th instar larvae, pupae and adults. The structure of bacterial community differed across the life stages of C. medinalis. Our findings will enrich the understanding of gut bacteria in C. medinalis, and will provide foundation and assistance for the development of novel pest management strategies through utilization of microbiota.

Rice seeds germinating in flooded soils encounter hypoxia or even anoxia leading to poor seed germination and crop establishment. Introgression of AG1 and AG2 QTLs associated with tolerance of flooding during germination, together with seed pre-treatment via hydro-priming or presoaking can enhance germination and seedling growth in anaerobic soils. This study assessed the performance of elite lines incorporating AG1, AG2 and their combination when directly seeded in flooded soils using dry seeds. The QTLs were in the background of two popular varieties PSB Rc82 and Ciherang-Sub1, evaluated along with the donors Kho Hlan On (AG1) and Ma-Zhan Red (AG2) and recipient parents PSB Rc82 and Ciherang-Sub1. In one set of experiments conducted in the greenhouse, seedling emergence, growth, and carbohydrate mobilization from seeds were assessed. Metabolites associated with reactive oxygen species (ROS) scavenging including malondialdehyde (MDA) as a measure of lipid peroxidation, ascorbate, total phenolic concentration (TPC), and activities of ROS scavenging enzymes were quantified in seeds germinating under control (saturated) and flooded (10 cm) soils. In another set of experiments conducted in a natural field with 3–5 cm flooding depths, control and pretreated seeds of Ciherang-Sub1 introgression lines and checks were used. Flooding reduced seedling emergence of all genotypes, though emergence of AG1 + AG2 introgression lines was greater than the other AG lines. Soluble sugars increased, while starch concentration decreased gradually under flooding especially in the tolerant checks and in AG1 + AG2 introgression lines. Less lipid peroxidation and higher α-amylase activity, higher ascorbate (RAsA) and TPC were observed in the tolerant checks and in the AG1 + AG2 introgression lines. Lipid peroxidation correlated negatively with ascorbate, TPC, and with ROS scavengers. Seed hydro-priming or pre-soaking increased emergence by 7–10% over that of dry seeds. Introgression of AG2 and AG1 + AG2 QTLs with seed pretreatment showed 101–153% higher emergence over dry seeds of intolerant genotypes in the field. Lines carrying AG1 + AG2 QTLs showed higher α-amylase activity, leading to rapid starch degradation and increase in soluble sugars, ascorbate, and TPC, together leading to higher germination and seedling growth in flooded soils. Seed hydro-priming or pre-soaking for 24 h also improved traits associated with flooding tolerance. Combining tolerance with seed management could therefore, improve crop establishment in flooded soils and encourage large-scale adoption of direct seeded rice system.

Funding was provided fully by USAID-sponsored Partnerships for Enhanced Engagement in Research (PEER) Program's Cycle 6 project, entitled “Ecosystem services in a changing climate; assessing critical services in Bangladesh rice production landscapes.” PEER is implemented by U.S. National Academy of Sciences (NAS) via USAID and NAS Prime Agreement No. AID-OAA-A-11-00012. D.L. (US partner on the PEER grant) acknowledges support from the National Science Foundation Long-term Ecological Research Program (DEB 1832042) at the Kellogg Biological Station, Michigan State University South Asia Partnership and MSU AgBioResearch. Since independence and over the years, pesticides have become a dominant feature of Bangladesh agriculture. To protect farmers' health, environment and to improve sustainability of chemical pest control quantitative understanding of farmers' behavior in pesticide use is critical. However, study on the levels of knowledge and awareness of farmers and the practices of pesticide use are often limited. We conducted a broad analysis on the effects of knowledge and awareness of farmers as well as the influence of the different associated stakeholders such as pesticide retailers and the government, on farmers' behavior in pesticide use from a detailed survey of 917 agricultural households in different regions of Bangladesh. Within eight protective behaviors (PBs) or PPEs were largely influenced by the crops growers and regions. Never discarding empty pesticide containers in the field, never applying pesticides more than prescribed by DAE or the instruction manual, selecting new types of pesticides recommended by DAE and purchasing low toxicity pesticides were the most adopted practices. Most farmers from the South-East region were adopting the PB of wearing mask, gloves and long sleeved clothes when spraying and farmers from South trusted the recommendations of pesticides by village leaders and neighbors. Majority of vegetables growers were well informed that pesticides were very harmful to the quality of agricultural products, the environment, and human health but not rice or mixed crops growers. Generally, PBs were positively affected by the perception of the consequences of farmers' behavior and knowledge of pesticide use but negatively influenced by action of governments and trust of retailers. It is important to recognize the differences that exist among different crops growers and locations. Attempt needs to bridge the gap among crop growers, locations and different stakeholder such as government agencies and retailers to develop policy. Publisher PDF

Nilaparvata lugens (Stal) is a serious threat to rice production in Asian countries. Synthetic chemicals are widely used for its control. However, evolution of resistance in this pest to commonly used insecticides has been recorded during the last decades. In this study, we determined and compared current insecticide resistance levels of thirteen N. lugens populations from China and Bangladesh to eight insecticides by rice-stem dipping method. These results showed that N. lugens had developed high levels of resistance to imidacloprid (resistance ratio, RR = 2491.0–8078.5-fold), thiamethoxam (RR = 303.6–1253.6-fold), buprofezin (RR = 175.7–365.1-fold) and dinotefuran (RR = 49.9–596.0-fold), low to moderate levels of resistance to nitenpyram (RR = 12.1–67.3-fold) and sulfoxaflor (RR = 3.8–25.5-fold), but were susceptible to triflumezopyrim (RR = 0.2–1.1-fold) in China. Meanwhile, increased activities of detoxification enzymes (EST, GST and P450) were found in multiple-resistant FY19 field population, which also showed the significant changes in the expression levels of P450s compared to susceptible strain, especially CYP6ER1 (11.04-fold). In contrast, first report of insecticide resistance in Bangladesh showed high levels of resistance to imidacloprid (RR = 3680.1–4430.8-fold) and thiamethoxam (RR = 144.3–737.9-fold), low to moderate levels of resistance to dinotefuran (RR = 38.7–57.9-fold), buprofezin (RR = 28.5–149.1-fold) and nitenpyram (RR = 3.4–14.1-fold). In addition, significant differences in insecticide resistance level of N. lugens to nitenpyram and dinotefuran were observed between two countries in 2020. The present study will be beneficial for implementing effective resistance management strategies to prevent or delay resistance development in N. lugens.

To know the position, problems and suggestion of harvest mechanization of rice, the study conducted in 21 upzillas under seven regions (Dhaka, Mymensingh, Sylhet, Comilla, Bogra, Rajshahi and Rangpur) based on different agro-climatic condition and cropping intensity and 126 farmers participated in the interview. For collecting data, a structured questionnaire was used and statistical analysis of the collected data was carried out. In study area, the average cultivable area was 225 to 1239 decimal (1 decimal = 40 m2) and 97.60% farmer reaping by sickle and only 0.80% used combine harvester. Cut paddy transported by head (13.49%), shoulders (12.7%) or both of them of 11.11% farmer and 44.44% of farmers used small truck or field threshed. Threshing was mainly done using (49.21%) closed drum thresher and open drum thresher (26.20%), likewise 1 of 126 farmer use head-feed combine harvester. The study area, most farmers (37.3%) used kula for the cleaning of rice, but only 8.74% of farmers used winnower. In considerable amount, 80.95% of farmers had machinery, while the remaining (19.05%) did not have machines. Farmers agreed that harvesting was a labor-intensive method (35.71%) and time consuming (28.57%). Transporting of harvested paddy was dangerous and painful for head, shoulder, hand, waist, backbone, leg, etc. With mechanization and the introduction of machinery, 40.48% of farmers identified the main ceiling as the price of the machine and information/lack of credit system (21.43%). In survey area, most farmers (36.51%) identified the vital advantage of mechanized harvesting as lower labor requirement, while 21.43% of farmers said that a lower loss of rice. All farmers who participated in the interview expressed their need for machinery and mentioned agricultural credit with easy terms and conditions, subsidy for buying machinery and the ensuring of a fair market price for their rice.

Recently, the integrated landscape approach has gained increasing interest of the scientific community, as well as of organizations active in the field of sustainable development. However, the enthusiastic welcome is challenged by little consensus on theory, terminology and definitions. Moreover, the operationalization of the approach into practice is a major challenge. In this paper, we present a framework to operationalize the integrated landscape approach in practice by putting a long-term collaboration between scientists and various stakeholder at center stage. Based on encompassing understanding of landscape-level processes and interactions, four pillars addressing different steps of a joint-learning circle are described and illustrated with examples. We consider the integrated landscape approach to be a prime way of targeting the Sustainable Development Goals (SDGs), but novel forms of collaboration between scientists and other stakeholders based on long-term commitments will be needed for operationalization in practice.

doctoral, 創造科学技術大学院, 甲第889号

An Energy Dispersive X-ray Fluorescence (EDXRF) method using X-ray emitting isotopes in combination with pre-concentration by carbonization was developed to determine the levels of Mo and Pb accumulated in foods. The samples were carbonized at temperatures range of 150–400°C for 15 min to 2 h for powdering. The powder was then quickly formed into a pellet for EDXRF analysis. This analytical method (detection limit, 0.08 mg/kg) was used to determine levels of Mo and Pb in several kinds of foods from the local kitchen markets. The analytical results indicated that higher concentration of Mo (2.51 ± 0.09 mg/kg) and Pb (0.62 ± 0.13 mg/kg) was present in pulse. The maximum lead concentration is also found in pulses with the mean value of, which is far below the maximum permissible limit (ASP, pp 235, 1980) of Pb in food (1–5 mg/kg). The possibility of determination of traces of Mo and Pb in foods by x-ray fluorescence after carbonization is evaluated by comparative studies of standard reference materials. The method enables fast and direct analysis to be carried out without lengthy sample pretreatment and thereby minimizing sample contamination on a routine basis for food monitoring. No loss (