فهرست مطالب resham bahadur thapa

The study on "biorational management of Maize Stem Borer, Chilo partellus (Swinhoe) in Farmer's field condition was done from March - August, 2019. Seven maize stem borer management namely; Spinosad 45% SC 0.5 mL L-1; Super-D (Chlorpyriphos 50% EC + Cypermethrin EC) @1.5 mL L-1; Nimbicidine (Azadirachtin 300 ppm)) 5 mL L-1; Daman (Beuveria bassiana) 3 mL L-1; Kalichakra (Metarhyzium anisopliae) @2.5 mL L-1; Emamectin benzoate 6% WP @0.2 g L-1 and control were used in Randomized Complete Block Design with three replications. Data were recorded on vegetative growth, damage assessment, yield and yield attributes. The damage assessment recorded at 3, 7 and 12 days after treatment application. There was lower percentage of damaged plant (0.83%) recorded in Spinosad 45% SC sprayed plot. Both stem exit hole and average tunnel length were statistically lower in the plot sprayed with Spinosad 45% SC and Choloropyriphos 50% + Cypermethrin 5% EC. Both insecticides namely Spinosad 45% SC and Choloropyriphos 50% + Cypermethrin 5% EC produced higher grain yield (8670 Kg ha-1 and 8620 kg ha-1 respectively) of maize as compared to other treatments. Nimbicidine treated plot produced 6900 kg ha-1 grain yield which was statistically better than Beuveria bassiana, Metarhyzium anisopliae, Emamectin benzoate and control. The overall result showed that safer pesticide like Spinosad followed by Nimbicidine are effective for the management of maize stem borer. Rrepeated trails over the seasons and varieties would help to reduce the infestation of maize stem borer.

A field experiment was conducted in a single factor randomized complete block designed to evaluate the effect of net house and mulching on insect pest incidence of tomatoes in Chitwan, Nepal from October 2016 to May 2017. Five different treatments were selected with four replications, included net house with black polythene mulch, black polythene mulching only, reflective polythene mulching only and black polythene mulching with emamectin benzoate 5% SG spray and control (no mulch+ no net + no pesticide spray). The production of crops in the open fields is constrained by major pests like Tuta absoluta and tomato fruit borer. The result revealed that the net house totally restricts the tomato fruit borer and Tuta absoluta whereas black mulching with emamectin benzoate spray plot reduced tomato fruit borer and Tuta absoluta larvae up to 69% and 59%. Total marketable yield was found the highest inside net house 47.74% higher than that of control plot. Damage fruit percent was found the highest in the control plot (28.36%) followed by reflective polythene mulching (21.48%) and black polythene mulching only (18.41%) and the lowest inside the net house (6.04%). Net profit was found maximum inside the net house (Rs1626632.88 ha-1 ) followed by black polythene with emamectin benzoate (Rs1141741.56 ha-1 ) and the lowest in the control plot (Rs760277.00 ha-1 ). Although the investment level found to be the highest in the case of the net houses in long term, higher income can be acquired as it acts as suitable means to control insect pests.

Aphids are the important insect pest of winter season vegetable crops such as cabbage, cauliflower, mustard in Nepal. Their damage in these crops not only reduces the potential yields but also affects the market quality of those crops. Pesticides management practices are the common to reduce their infestation and crop damage. Judicious use of soft chemicals not only improve the farmers' health but also protect pollinator and beneficial soil arthropods. Therefore, a field study was conducted to test the commonly used alternative safe measures (bio-pesticides, home-made and chemical) in RCBD in a four replicates design in cauliflower crop cv. Snow Mystique. These were Mahashakti (Bt.), Neemix (Azadirachtin), Spinosad (bacteria-based), Liquid manure (a mixture of succulent plants, cow urine, fresh cow dung and ash) and Cypermethrin-10 (Superkiller-10). The study suggested that Cypermethrin-10 treated plots followed by Liquid manure and Spinosad was more effective to keep the aphid population below the threshold level than the control. The highest cauliflower curd yield was recorded in Cypermethrin treated plot (42.3 mt ha-1 ) followed by Spinosad. This study suggests that chemicals are superior in terms of population reduction and crop yield but these were not eco-friendly and sustainable. Hence, integrating these chemicals to other bio-pesticides could be an alternative to aphid as well as other pest management.

A field experiment was conducted to determine the comparative efficacy of different eco-friendly management practices against maize stem borers, Chilo partellus (Swinhoe) and Sesamia inferens (Walker) in maize under field condition during spring season for two consecutive years, 2017 and 2018. The experiment was laid out in a randomized complete block design with four replications and seven treatments, namely: i) Trichogramma chilonis (Ishii) (egg parasitoids) @100000 eggs ha-1 , ii) Nimbicidine 0.03% (Neemax)-commercial product of neem @ 3.0 mL L-1 of water, iii) Spinosad 45% SC (Tracer) -bio-insecticide @ 0.5 mL L-1 of water, iv) Bacillus thuringiensis108 cfu mL-1 (Mahashakti)-bio-insecticide @ 2 mL L-1 of water, v) maize intercropping with cowpea (1:1 ratio), vi) Chlorpyrifos 20% EC (Dursban)- chemical insecticide @ 2 mL L-1 of water, and vii) Untreated control (without application) at the National Maize Research Program, Chitwan, Nepal. The efficacy study revealed that all the treatments significantly reduced leaf and stem injuries and increased grain yield over untreated check (p<0.05). The treatment, chlorpyrifos 20% EC was found effective with minimum percent infestation in both leaf (5.51%) and stem (1.86%) injury followed by spinosad 45% EC and T. chilonis respectively. Similarly, spinosad 45% EC gave significant result with the highest grain yield (4.66 mt ha-1 ) followed by Chlorpyrifos 20% EC (4.57 mt ha-1 ) and maize + cowpea intercropping (4.23 mt ha-1 ) as compared to untreated control (2.91 mt ha-1 ). Maize + cowpea (1:1) intercropping and release of T. chilonis were at par statistically and proved safer to natural enemies as compared to the chemical insecticides.

Although Ginger is the main cash crop for small farmers across the country, there are many problems associated with the cost of product. The study was conducted in four ginger growing areas (60 farmers from each area) of Palpa, Nepal in 2012. Study was focused on cost factors for various inputs and problem of production. The study revealed that benefit cost ratio for ginger production was profitable on cash cost basis (7.22). Seed has major cost share for ginger production (65.1%). The estimated coefficients of Cobb-Douglas production function showed that seed, labor and number of years for crop rotation were the significant factors for ginger production. Major problems faced by farmers were availability of source seed and pest management. Study concluded that ginger production can be made viable enterprise with increased focus on managing source seed and plant protection.

Stemphylium species are pathogenic to a number of crops under broad geography and diverse environments. Stemphylium blight of lentil (Lens culinaris Medik) caused by Stemphylium botryosum Walr is becoming a serious emerging threat to lentil cultivation and become widespread throughout major legume growing areas in Nepal. Lentil was sown in different dates to observed incidence and severity of stemphylium blight in Rampur, Chitwan during two consecutive years 2012-2014. Lentil seeds sown up to middle of November escaped the disease severity and also resulted higher yield compared to other dates. Disease severity increased with the advancement of sowing date from November 1 to December 21 with decreased yields. The trends of disease development were similar in both years. The maximum and minimum temperatures, total rainfall and sunshine hour ranging from 22.42-24.23°C (mean 23.32°C), 4.12-13.00°C(mean 8.56°C), 9.6-30.5mm (mean 24.85mm) and 200.05-309.85 hour (mean 254.95 hour) respectively were favorable for disease development. A multiple linear regression model with temperature, rainfall and sunshine hourswas developed to predict stemphylium blight disease severity on lentil plants.