scholarly journals Economic Management of Late Blight (Phytophthora infestans L.) of Potato in Eastern Tarai of Nepal

1970 ◽  
Vol 6 ◽  
pp. 57-61 ◽  
Author(s):  
Prem CP Chaurasia

Field experiments were carried out at Regional Agriculture Research Station, Tarahara in threeconsecutive years (1997-2000) during winter season to know the economic sprays of differentfungicides to manage late blight disease of potato. Late blight susceptible cultivar of potatoKufri Sindhuri was used for the experiment. Krinoxyl gold (metalaxyl 8% and mancozeb 64%)at the rate of 1.5 g/l, Dithane M- 45 (mancozeb 75%) @ 0.3% and Bordeaux mixture @ 10 gcopper sulfate and 10 g lime/l of water and their different combinations were tested inrandomized complete block design with three replications. Terminal disease severity was thehighest (7.9) on 0-9 scale disease rating in unsprayed check and it was significantly higher thanthose of other fungicides sprays. Plots with three sprays of Dithane M- 45 @ 0.3% recorded thelowest (2.4) terminal disease severity. Disease development was the fastest in the unsprayed plotcompared to all other treatments. Similarly apparent infection rate was the highest in unsprayedtreatment. Area Under the Disease Progress Curve was also the highest in unsprayed plot and itwas significantly higher than those of other treatments. Tuber yield was the lowest (3.93 kg/4.5m2 plot in unsprayed and the highest (6.08 kg), in the plot receiving four sprays of Dithane M-45@ 0.3 % and this was at par with the tuber yield of plots receiving two and three sprays ofDithane M-45. Benefit cost ratio was the highest (1.54) in case of two sprays of Dithane M-45@ 0.3% at 10 days intervals. All others fungicide spays were uneconomical under Eastern Taraicondition.Key words: Eastern Tarai; economic spray; Dithane M-45; late blight management; potatoDOI: 10.3126/narj.v6i0.3365Nepal Agriculture Research Journal Vol.6 2005 pp.57-61

2020 ◽  
Vol 7 (03) ◽  
Author(s):  
S. K. YADAV ◽  
R. K. SINGH ◽  
V. K. DUA ◽  
S SINGH ◽  
SARALA YADAV ◽  
...  

A field experiment was carried out during 2015-16 and 2016-17 at ICAR-Central Potato Research Station, Patna, Bihar, in randomized block design with four replications with objective to quantity the optimum requirement of nitrogen to potato crop. Significantly the highest plant height was recorded with nitrogen level of 300 kg/ha. Distributions of the smallest size of tuber yield of potato were decreasing with increasing the level of nitrogen. There was about 26.0% more yield of the smallest size tuber of potato was recorded with zero nitrogen as compare to the highest level of nitrogen i.e. 300 kg/ha. Increasing the nitrogen over the level of 150 to 225 kg per hectare, increasing the yield of tuber gradually slower rate than nitrogen level from 0 to 150 kg/ha. Total and marketable tuber yield of potato were increasing significantly with increasing level of nitrogen up to 150 kg/ha. There was no significant difference in marketable tuber yield was found for nitrogen level between 150 and 225 kg/ha. Highest (1.66) net benefit cost ratio was also recorded with level of nitrogen @ 150 kg/ha in potato. Hence, application of nitrogen @ 150 kg/ha was found statistically and economically more beneficial for potato cultivation in Eastern Indo-Gangatic plain of India.


2021 ◽  
Vol 4 (1) ◽  
pp. 165-175
Author(s):  
Lok Nath Aryal ◽  
Rajendra Regmi ◽  
Santosh Lohani ◽  
Yubaraj Bhusal

Cowpea (Vigna unguiculata Walp.) is a major grain legume used as vegetables and pulses. Among the several insect pest of cowpea, spotted pod borer is one of the most destructive pest. To evaluate the available chemical pesticides for pod borer management, a set of field experiments on cowpea variety Malepatan-1 were conducted at Horticulture Research Station, Malepatan, Pokhara in years 2019 and 2020. The experiments were laid out in Completely Randomized Block Design (RCBD) having seven  treatments viz.Flubendiamide 39.35 % SC @ 0.3 mL/L, Chlorantraniliprole 18.5 % SC @ 0.2 mL/L, Emamectin benzoate 5 % SG @0.3 g/L, Spinosad 45 % SC @0.3 mL/L, Bacillus thuringiensis Kurstaki @2g/L, Azadirechtin 0.03%@ 5mL/L and Control with four replications. Flubendiamide 39.35 % SC @ 0.3 mL/L and Emamectin benzoate 5 % SG @0.3 g/L were found the most effective insecticides in lowering cowpea flower and pod damage with highest benefit cost ratio; however, considering environment, Chlorantraniliprole 18.5 % SC @ 0.2 mL/L and Spinosad 45 % SC @0.3 mL/L being next effective treatments could be viable option to manage spotted pod borer in cowpea production.   


2018 ◽  
Vol 2 (1) ◽  
pp. 5-11 ◽  
Author(s):  
YOSEP SERAN MAU

Mau YS. 2018. Resistance response of fifteen sweet potato genotypes to scab disease (Sphaceloma batatas) in two growing sites in East Nusa Tenggara, Indonesia. Trop Drylands 2: 5-11. Field experiments were carried out in two growing locations involving potential sweet potato clones from East Nusa Tenggara Province, Indonesia to: (i) evaluate scab resistance levels of the sweet potato clones, and (ii) identify sweet potato clones with good resistance level to scab disease. The experiment was carried out in the fields employing a Randomized Block Design with a mono-factorial treatment design in each location. The treatment assigned was sweet potato genotype, each consisted of two replicates. The variables observed were disease severity that was assessed at 2, 4, 6, and 8 weeks after inoculation (WAI), which then was used to calculate the Area Under the Disease Progress Curve (AUDPC) of the disease severity. The ANOVA of AUDPC was used to determine the treatment effect, and the disease severity at 8 WAI was used to assess scab resistance level of the sweet potato genotypes tested. The study results showed highly significant differences of disease severities among the tested sweet potato genotypes within each trial location. The majority of the genotypes tested were classified "resistant" or "moderately resistant" to scab disease, except the check clone SLM-01 and KRA-01 that were, respectively, "susceptible" and "moderately susceptible" to scab disease. The majority of sweet potato genotypes evaluated were consistent in their resistance performance in the two trial locations.


2016 ◽  
Vol 1 ◽  
pp. 1-8 ◽  
Author(s):  
Bedanand Chaudhary

In present study physical resistance test on 12 rice varieties against sheath blight (ShB) caused by Rhizoctonia solani was examined. A detached tiller test was used to measure components of ShB physiological resistance at Regional Agricultural Research Station (RARS), Tarahara, Nepal. The varieties were evaluated in a randomized complete block design (RCBD) with 3 replications in year 2010-12. A sclerotium was inserted below the leaf collar of individual tillers maintained in tubes filled with water. Only the 56-day old susceptible plants were inoculated. After 7 days of inoculation, number of lesions, dead leaves, vertical sheath colonization and disease severity were measured. In 2011, field experiments were conducted with three replications to address morphological resistance in 28 rice genotypes. Disease incidence was recorded on 14, 21 and 28 days after inoculation. The number of dead leaves differed only numerically while disease variables significantly (P=0.004) varied among varieties. The other variables were highly correlated with each other. Cluster analysis of variables formed three varietal groups; Sabitri with lowest, and Jasmine-85 and Betichikon having highest values. Rice genotypes differed significantly (P=0.05) for disease incidence and area Under Disease Progress Curve (AUDPC). Tetep and IAC-165 had the lowest and highest terminal disease incidences and AUDPC, respectively. Sabitri, MTU-1010 and IR-26 recorded lower AUDPC values. Hence, Tetep and Sabitri could be used as donors in hybridization and their plant morphology could be considered as selection guide for improving ShB resistance in rice.Journal of Nepal Agricultural Research Council Vol.1 2015 pp.1-8


2019 ◽  
Vol 32 (2) ◽  
pp. 390-398
Author(s):  
VICTOR HUGO CASA-COILA ◽  
CESAR BAUER GOMES ◽  
ISRAEL LIMA-MEDINA ◽  
DEDIEL JUNIOR AMARAL ROCHA ◽  
ARIONE DA SILVA PEREIRA ◽  
...  

ABSTRACT The in vitro and field reactions of 23 potato cultivars and clones to two isolates of Phytophthora infestans were tested. The in vitro test used the detached potato leaflets method, and disease severity was evaluated 6 days after inoculation. Field experiments were conducted in autumn of 2013, in two locations in Pelotas City, Rio Grande do Sul State, Brazil. Seven evaluations of the disease severity were performed. From the severity values, the area under the disease progress curve (AUDPC) was calculated. Tubers were harvested to determine the yield (g plot-1). The A2 mating type isolate was the most aggressive for the majority of the potato genotypes. It was possible to group the different reactions of the potato genotypes based on the AUDPC values. Clones C2553-1-06, C2573-4-06, C2550-4-06, C2551-2-06, and CIP392,617.54 showed moderate-to-high resistance to the two isolates of P. infestans. The values of severity and AUDPC obtained in vitro and field tests were positively correlated for both P. infestans isolates, but in some interactions, inconsistencies were observed. Tuber yield was negatively correlated with AUDPC.


2020 ◽  
Vol 57 (3) ◽  
pp. 199-210
Author(s):  
Rajib Kundu ◽  
Mousumi Mondal ◽  
Sourav Garai ◽  
Ramyajit Mondal ◽  
Ratneswar Poddar

Field experiments were conducted at research farm of Bidhan Chandra Krishi Viswavidyalaya, Kalyani, West Bengal, India (22°97' N latitude and 88°44' E longitude, 9.75 m above mean sea level) under natural weed infestations in boro season rice (nursery bed as well as main field) during 2017-18 and 2018-19 to evaluate the herbicidal effects on weed floras, yield, non-target soil organisms to optimize the herbicide use for sustainable rice-production. Seven weed control treatments including three doses of bispyribac-sodium 10% SC (150,200, and 250 ml ha-1), two doses of fenoxaprop-p-ethyl 9.3% EC (500 and 625 ml ha-1), one weed free and weedy check were laid out in a randomized complete block design, replicated thrice. Among the tested herbicides, bispyribac-sodium with its highest dose (250 ml ha-1) resulted in maximum weed control efficiency, treatment efficiency index and crop resistance index irrespective of weed species and dates of observation in both nursery as well as main field. Similar treatment also revealed maximum grain yield (5.20 t ha-1), which was 38.38% higher than control, closely followed by Fenoxaprop-p-ethyl (625 ml ha-1) had high efficacy against grasses, sedge and broadleaf weed flora. Maximum net return (Rs. 48765 ha-1) and benefit cost ratio (1.72) were obtained from the treatment which received bispyribac-sodium @ 250 ml ha-1. Based on overall performance, the bispyribac-sodium (250 ml ha-1) may be considered as the best herbicide treatment for weed management in transplanted rice as well as nursery bed.


2016 ◽  
Vol 41 (4) ◽  
pp. 713-723
Author(s):  
S Akther ◽  
F Ahmed ◽  
MR Islam ◽  
MA Hossen ◽  
AHMM Rahman Talukder

Field experiments were carried out in the Agronomy field of BARI, Joydebpur, RARS, Jamalpur and RARS, Ishurdi during two consecutive kharif seasons of 2012 and 2013 to determine the suitable plant spacing and optimum fertilizer dose for higher yield of mukhikachu. Three levels of spacing viz., 60 cm x 60 cm, 60 cm x 45 cm and 60 cm x 30 cm and three levels of fertilizer dose viz., recommended dose (3000-96-27-81-18 kg ha-1 of CD-N-P-K-S), 25% less than the recommended dose and 25% higher than the recommended dose were used as treatment variables. The experiments were laid out in factorial randomized complete block design with three replications. Results revealed that the closer spacing (60 cm x 30 cm) in combination with 25% higher than the recommended fertilizer dose gave the maximum edible yield of mukhikachu (two years average) at all locations (20.04 t ha-1, 20.75 t ha-1 and 16.63 t ha-1 at Joydebpur, Jamalpur and Ishurdi, respectively). The wider spacing (60 cm x 60 cm) coupled with 25% less than the recommended fertilizer dose produced the lowest yield (two years average). The maximum benefit- cost ratio (two years average) was obtained from the combination of the recommended fertilizer dose and 60 cm x 30 cm spacing, that were 2.93 at Joydebpur and 3.42 at Ishurdi, while at Jamalpur the maximum benefit-cost ratio (two years average) was found maximum from 60 cm x 30 cm spacing with 25% higher than the recommended fertilizer dose (3.12).Bangladesh J. Agril. Res. 41(4): 713-723, December 2016


2016 ◽  
Vol 83 (0) ◽  
Author(s):  
Jesus Guerino Töfoli ◽  
Ricardo José Domingues ◽  
Walter Jacobelis Jr. ◽  
Marina Pacheco Lombardi Tortolo

ABSTRACT: Late blight (Phytophthora infestans ) is among the most important and destructive diseases in potato cultivation. Aiming to evaluate the efficacy of the new fungicide ametoctradin, mixed with dimethomorph and metiram, an experiment was carried out in commercial potato crops (Ágata cultivar) in Pilar do Sul, São Paulo state, Brazil, during the growing season in 2013. A randomized block design was used, with 4 replications, on plots of 15 m2. Applications were carried out using a backpack sprayer with a spray-bar under 3 bar of constant pressure. The application volume varied from 300 L to 600 L.ha-1 based on crop development. The variables evaluated were leaf severity (0 to 100%), area under the disease progress curve, and yield. Ametoctradin + dimethomorph (1.25 L.ha-1) provided significant control of late blight, exceeding benthiavalicarb + fluazinam, dimethomorph + metiram, dimethomorph + pyraclostrobin, cymoxanil + mancozeb, metalaxyl-M + mancozeb, ametoctradin + metiram, and pyraclostrobin + metiram, although similar to ametoctradin + dimethomorph (1.00 L.ha-1), fluopicolide + propamocarb, and fenamidone + propamocarb. Ametoctradin + metiram resulted in moderate control, which was always similar to the standard. Ametoctradin and its associations represent a new alternative for the management of potato late blight.


2017 ◽  
Vol 9 (1) ◽  
pp. 291-297
Author(s):  
Pravin Singh ◽  
Kavita Aravindakshan ◽  
I. B. Maurya ◽  
Jitendra Singh ◽  
Bhim Singh ◽  
...  

A field experiment was conducted to study the effect of different levels of potassium and zinc on growth, yield and economics of sweet potato. The experiment was laid out on clay and loam soil by adopting randomized block design with factorial technique (FRBD). The sixteen treatments consisted of combination of four levels of po-tassium (0, 80, 100 and 120 kg/ha through muriate of potash and four levels of foliar zinc (control i.e. water spray, 10, 20 and 30ppm) through zinc sulphate. The individual application of potassium 120 kg K2O/ha significantly in-creased the number of tubers per plant (4.60), average weight of tuber (275.31 g), length of tuber (16.77 cm), diam-eter of tuber (5.69 cm), tuber yield per plot (9.71 kg), tuber yield per hectare (49.04 t) respectively as compared to control. With the foliar application of zinc (30 ppm) significant increase in number of tubers per plant (4.18), average weight of tuber (234.73 g), length of tuber (18.12 cm), diameter of tuber (5.16 cm), tuber yield per plot (8.33 kg) and tuber yield per hectare (42.05 t) was recordedas compared to control. The treatment combination (120 kg K2O+30ppm Zn) recorded the maximum yield parameters i.e. chlorophyll content (37.00 mg/100 g), average weight of tuber (302.17 g), length of tuber (19.82 cm), diameter of tuber (5.97 cm), maximum tuber yield per plot (11.02 kg), tuber yield per hectare (55.67 t) and benefit-cost ratio (B: C ratio) of 4.22:1.While, the treatment (120 kg K2O+30ppm Zn) had the maximum number of tuber (4.86), minimum number of tuber was recorded in control. From the experi-ment, it appeared that application of potassium and zinc can be used to improve yield and higher net monetary re-turns of sweet potato.


2020 ◽  
Vol 46 (3) ◽  
pp. 191-197
Author(s):  
Nilceu Ricetti Xavier de Nazareno ◽  
Maria Renate Finckh ◽  
Lutécia Beatriz dos Santos Canalli ◽  
Inês Fumiko Ubukata Yada ◽  
Jackson Kawakami

ABSTRACT Field experiments were conducted during spring 2014 and fall and spring 2015 to determine the effect of fresh mulch on the development of Phytophthora infestans epidemics, in Lapa Municipality, Parana State, southern Brazil. The used cultivars were ‘Agata’, susceptible, and ‘BRS Ana’, moderately susceptible. The main treatment consisted in manually applying a 10cm-thick layer of fresh mulch when potato sprouts were emerging. Fresh mulch was prepared with plants available at that time of the year. For the spring experiments, fresh mulch was a mixture of oats, rye grass and wild radish (60 t/ha) and for the fall experiment, semi-ripe elephant grass (90 t/ha). Plots consisted of six 10m-long rows, spaced at 0.8m, containing 28 plants per row. Experimental design was in completely randomized blocks with four replicates. Natural inoculum was adopted. Percentage of leaf area was weekly estimated until the end of the plant cycle and the area under the disease progress curve (AUDPC) was calculated. Application of fresh mulch significantly reduced AUDPC by 32.1%, 12.4% and 23.1%, compared to control in all seasons, for ‘BRS Ana’ and by 26.1%, 2.8% and 12.0% for ‘Agata’. Application of fresh mulch showed to be a promising practice for the integrated management of late blight and for the protection of yields, especially in periods more favorable to the development of the disease. More detailed studies should be conducted on the plant type and amount of fresh mulch to be used, as well as on the possibility of reducing concentrations or increasing intervals between fungicide sprays.


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