The brown planthopper, Nilaparvata lugens (Stål) is a destructive rice pest found in almost all the rice-growing areas across the globe. In pest management strategies, insecticides are the vital element to control this insect pest. But recently their heavy use poses a risk of control failure because of the development of insecticide resistance. Quick insecticide resistance development nature in N. lugens intrigued scientists to understand the complex resistance mechanism(s), side by side pledge the importance of regular monitoring to know the trend of resistance development. Resistance mechanisms like, target-site insensitivity and enhanced activity of detoxifying enzymes, have been extensively studied and identified in governing the resistance development of N. lugens. Both the field collected and laboratory selected pest populations were tested against commonly used insecticides to detect insecticide resistance ratio. In this review, recent findings of resistance mechanisms, candidate genes those contribute in resistance development have been summarized. We also provide an insight into the metabolic resistance mechanisms that confer significant levels of resistances and the current status of insecticide resistance in N. lugens. This review will help to get a clearer view on present research directions of insecticide resistance in N. lugens.
The study was conducted at the research field of Olericulture Division, Horticulture Research Centre, Bangladesh Agricultural Research Institute (BARI), Gazipur to study the relationship among fruit setting and flower types and yield potentials of brinjal under summer condition during May to November 2013. Fourteen germplasms were evaluated in a Randomized Complete Block Design with three replications. Marked variation was observed among the studied germplasms. The lowest number of clusters per plant (13.78) and it was highest (6.31) recorded from the genotype SM 011. The total floral bud(s) per plant was recorded highest in SM 58-1 and SM 58-2 (127.62) and the lowest from SM 021 (37.31). The highest percentage of long styled flowers per plant counted from the genotype SM 58-1 (64.37%). The highest percentage of medium styled
Original Research Articleflower was counted from the genotype SM 200 (34.15%). BARI Begun -4 and SM 211 had the highest fruit setting percentage 75.17% and 72.56%, respectively. The lowest fruit setting percentage was recorded from the genotype SM 235 (30.27%). The highest yield loss per plant due to pest infestation was recorded from the genotype SM 58-2 (304.00 g) and the lowest from the genotype SM 011 (100.17 g). BARI Begun -4 produced the maximum number of edible fruits per plant (32.13) and BARI Begun -5 produced the minimum number of edible fruits per plant (8.10). The yield (edible fruit) per plant was found the highest in BARI Begun -4 (2.62 kg) and the lowest in SM 011(0.92 kg). The highest individual fruit weight (304.00 g) was obtained in EGN 10 and the lowest was 55.10 g in SM 011. Fruit setting percentage and yield were found more in that germplasms which produced relatively higher percentage of long and medium styled flower.
This study was conducted at Kamalganj Upazila of Moulvibazar District in Bangladesh during January to September 2015 to explore the impact of homestead agroforestry on the socio economic condition of the respondents and to explore their relationships with the selected characteristics of the respondents. Face to face interview was performed with 135 respondents to collect the data with the help of questionnaire. Eight different characteristics of the farmers namely; educations, farm size, homestead size, annual income, annual expenditure, savings, knowledge on homestead agroforestry, socio-economic class of the respondents showed significant positive relationships with the numbers of diversified plant species, while negative relationship of diversified plant species was observed with age and family size. Agro forestry based practices plays a vital role to uplift the socio-economic classes of the respondents. For uses of agroforestry products, annual savings and expenditures the highest decisions comes from females 45% and 41% followed by male 38% and 39% respectively. In other cases also female participation is greater than male respondents. Results conclude that homestead agroforestry is a unique area for maintaining both plant diversity and productivity for farmers’ livelihood in the studied area.
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