Light-induced alteration of leaf sterol content and late blight disease development in tomato

1982 ◽  
Vol 60 (12) ◽  
pp. 2724-2728 ◽  
Author(s):  
B. Bradford ◽  
L. D. Moore ◽  
D. M. Orcutt
Keyword(s):  
Light Intensity ◽  
Late Blight ◽  
Disease Incidence ◽  
Total Sterol ◽  
Disease Development ◽  
Low Light ◽  
Light Intensities ◽  
Intensity Changes ◽  
Late Blight Disease ◽  
Blight Disease

‘Nova’ and 'Beefsteak,' cultivars of tomato (Lycopersicon esculentum Mill.), were grown in chambers under light intensities of 240 or 120 μE∙m−2∙s−1. Thirty-five days after seeding, half of the tomato plants were harvested for sterol analysis and the others were inoculated with a tomato race O isolate of Phytophthora infestons (Mont.) de By. Late blight symptoms were assessed 10 days after inoculation from the number of leaves showing disease (disease incidence) and the amount of blighted area of each leaf (percent colonization). Disease incidence and percent colonization were not influenced by light intensity with 'Nova' plants, but 'Beefsteak' plants grown under low light were significantly [Formula: see text] more diseased than those exposed to the higher light intensity. Changes in free sterol, steryl ester, and total sterol concentrations between plants grown under different light intensities were similar for both cultivars. A significant decrease in the steryl glycoside concentration of low light grown 'Beefsteak' plants correlated with increased disease incidence. The possible role of steryl glycosides and their derivatives in late blight disease development is discussed.

Efficacy of fungicides in controlling late blight of potato

2015 ◽  
Vol 26 (2) ◽  
pp. 103-108
Author(s):  
MM Anwar ◽  
A Parveen ◽  
MM Hossain ◽  
NU Mahamud ◽  
RK Roy
Keyword(s):  
Late Blight ◽  
Tuber Yield ◽  
Cultural Practices ◽  
Disease Incidence ◽  
Integrated Approach ◽  
Control Treatment ◽  
Commercial Potato ◽  
Late Blight Disease ◽  
Blight Disease ◽  
Late Blight Of Potato

Potato cultivars grown in Bangladesh have low levels of general resistance to late blight. As such, most commercial potato farmers rely on fungicide applications for control of Phytophthora infestans, the causal agent of late blight. Management of late blight of potato requires an integrated approach that includes rotation with non-hosts, resistant cultivars, cultural practices, and fungicides. The study on efficacy of some new fungicides against late blight disease of potato was conducted at ARS, Alamnagar Rangpur during rabi season 2010-2011 to select suitable fungicides against late blight of potato. Thirteen different fungicides were tested and all the tested fungicides showed significantly better performance over control. Considering percentage disease incidence T4,T6 and T12 showed better performance than all other treatment. In case of T4,T6 and T12 treatment disease reduction was more than 80 % over control. Significantly the highest tuber yield 25.5 t ha-1was obtained from T3  which was statistically similar to the yield of T2,T5 , T6, T9, T10, T11and T12  treatment whereas the lowest tuber  yield 14.5 t ha-1 was obtained from control treatment. Field experiment was conducted from 2010 to 2011 to investigate the comparative efficacy of the fungicides. In the field, applications of fungicide that preceded the largest incremental increase in disease incidence provided the best control of disease or increased yield.Progressive Agriculture 26 (2): 103-108, 2015

Responses of Branchiomma Vesiculosum (Montagu) to photic stimulation

1950 ◽  
Vol 29 (2) ◽  
pp. 303-320 ◽  
Author(s):  
J. A. C. Nicol
Keyword(s):  
Light Intensity ◽  
Red Light ◽  
Light Sensitivity ◽  
Photic Stimulation ◽  
Intensity Change ◽  
Low Light ◽  
Effective Stimulus ◽  
Light Intensities ◽  
Intensity Changes ◽  
Effective Intensity

In Branchiomma vesiculosum decrease in light intensity causes the animal to contract and withdraw into its tube. A decrease, never an increase, in illumination is the effective stimulus. When repeatedly stimulated the animals quickly become adapted to intensity changes and no longer respond.The minimal effective intensity change has been determined for a range of intensities. ΔI/I is found to increase in low light intensities, and to be fairly constant in intensities over 50 lux. The animals are least sensitive to red light; sensitivity increases in shorter wave-lengths.

scholarly journals Efficacy of Mancozeb and Ocimum gratissimum Extract in the Management of Late Blight Disease in Tomato Varieties

2020 ◽  
pp. 45-53
Author(s):  
Manju Evelyn Bi ◽  
Ache NehTeke ◽  
Nkwatoh Therese Ncheuveu ◽  
Bih Nadine Toh
Keyword(s):  
Late Blight ◽  
Disease Incidence ◽  
Block Design ◽  
Rio Grande ◽  
Fruit Weight ◽  
Ocimum Gratissimum ◽  
Randomized Block Design ◽  
Significant Difference ◽  
Late Blight Disease ◽  
Blight Disease

Tomato late blight is an economic disease that causes 100 % yield loss of tomato in Cameroon. The objective of the study was to determine the efficacy of mancozeb and Ocimum gratissimum extract in managing late blight disease in Nadira and Rio-grande tomato varieties. Seedlings of each tomato variety were planted in replicates of three in a complete randomized block design comprising of three treatments (T1 –Ocimum gratissimum extract (1666.7 g/15 L); T2 –Mancozeb (50 g/15 L); T3 –control. Fifty grams of mancozeb (50g) and 1666.7 g of O. gratissimum extract dissolved and mixed with water in a 15 L knapsack sprayer was applied to control tomato late blight from the onset of blight symptoms, at two days intervals, to control Data for the disease incidence, severity, and yield parameters were collected at weekly intervals for four weeks from plants in the middle of the ridges.  Mancozeb and O. gratissimum extract significantly reduced the disease severity of  Nadira and Rio-grande tomato varieties by 0.2., resulting in a mean fruit number of 18.31 and 16.31 fruits and fruit weight of 1.44 g and 1.13 g. There was no significant difference (p =0.05) between plants sprayed with Mancozeb and O. gratissimum extract. The Nadira variety was resistant to the tomato late blight caused by Phytophthora infestans. Thus biopesticides (O. gratissimum) can be effectively used as alternatives to synthetic fungicides (mancozeb) –which pose risks to human and environmental health.

scholarly journals Response of Local Potato Cultivars to Late Blight Disease (Phytophthora infestans (Mont.) de Bary) under Field Conditions

2020 ◽  
Vol 3 (1) ◽  
pp. 28-37
Author(s):  
Rishav Pandit ◽  
Ravi Bhatta ◽  
Pooja Bhusal ◽  
Basistha Acharya ◽  
Subash Subedi ◽  
...  
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Disease Incidence ◽  
Block Design ◽  
Potato Cultivar ◽  
Late Blight Resistance ◽  
Potato Cultivars ◽  
Late Blight Disease ◽  
Blight Disease ◽  
Moderately Resistant

Developing host resistance is an economic and long-term approach to disease management; however, resistance reactions that differ depending on the genotypes. Potato late blight is the devastating disease caused due to Phytophthora infestans (Mont.) de Bary.  In order to identify late blight resistance in potato genotypes, seven local potato cultivars (Bardiya Rato Local, Bardiya Seto Local, Cardinal, Deukhuri Rato Local, Deukhuri Seto Local, Kailali Local and Khumal Ujjowal) were evaluated in randomized complete block design (RCBD) with three replications during October 2018 to January 2019 on naturally infested soils in Deukhuri, Dang, Nepal. Results showed that significantly the highest disease incidence (99.17%), and the highest disease severity (88%) were found on Cardinal followed by Deukhuri Rato Local (64%), and Deukhuri Seto Local (60%). Potato cultivar namely Khumal Ujjowal was moderately resistant, whereas Deukhuri Rato local and Deukhuri Seto Local were susceptible to late blight disease. Significantly the highest yield (12.67 t ha-1) was produced by Khumal Ujjowal followed by Bardiya Rato Local (10.78 t ha-1) and Bardiya Seto Local (9.40 t ha-1). The disease incidence and Area under disease progressive curve (AUDPC) value was negatively co-related with the tuber yield. The potato cultivar Khumal Ujjowal followed by Bardiya Rato Local were found moderately resistant to late blight disease in Deukhuri conditions. This study suggests that potato cultivar Bardiya Rato Local can be grown for higher tuber production in Dang and similar topographic regions.

scholarly journals Response of Local Potato Cultivars to Late Blight Disease (Phytophthora infestans (Mont.) de Bary) under Field Conditions

2020 ◽  
Vol 3 (1) ◽  
pp. 28-37
Author(s):  
Rishav Pandit ◽  
Ravi Bhatta ◽  
Pooja Bhusal ◽  
Basistha Acharya ◽  
Subash Subedi ◽  
...  
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Disease Incidence ◽  
Block Design ◽  
Potato Cultivar ◽  
Late Blight Resistance ◽  
Potato Cultivars ◽  
Late Blight Disease ◽  
Blight Disease ◽  
Moderately Resistant

Developing host resistance is an economic and long-term approach to disease management; however, resistance reactions that differ depending on the genotypes. Potato late blight is the devastating disease caused due to Phytophthora infestans (Mont.) de Bary.  In order to identify late blight resistance in potato genotypes, seven local potato cultivars (Bardiya Rato Local, Bardiya Seto Local, Cardinal, Deukhuri Rato Local, Deukhuri Seto Local, Kailali Local and Khumal Ujjowal) were evaluated in randomized complete block design (RCBD) with three replications during October 2018 to January 2019 on naturally infested soils in Deukhuri, Dang, Nepal. Results showed that significantly the highest disease incidence (99.17%), and the highest disease severity (88%) were found on Cardinal followed by Deukhuri Rato Local (64%), and Deukhuri Seto Local (60%). Potato cultivar namely Khumal Ujjowal was moderately resistant, whereas Deukhuri Rato local and Deukhuri Seto Local were susceptible to late blight disease. Significantly the highest yield (12.67 t ha-1) was produced by Khumal Ujjowal followed by Bardiya Rato Local (10.78 t ha-1) and Bardiya Seto Local (9.40 t ha-1). The disease incidence and Area under disease progressive curve (AUDPC) value was negatively co-related with the tuber yield. The potato cultivar Khumal Ujjowal followed by Bardiya Rato Local were found moderately resistant to late blight disease in Deukhuri conditions. This study suggests that potato cultivar Bardiya Rato Local can be grown for higher tuber production in Dang and similar topographic regions.

scholarly journals Potato late blight disease prediction using meteorological parameters in Northern Himalayas of India

2021 ◽  
Vol 23 (3) ◽  
pp. 310-315
Author(s):  
W. A. DAR ◽  
F. A. PARRY ◽  
B. A. BHAT
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Late Blight ◽  
Weather Conditions ◽  
Potato Late Blight ◽  
Disease Development ◽  
Potato Blight ◽  
Late Blight Disease ◽  
Weather Parameters ◽  
Blight Disease

Weather parameters play an important role in the spread of potato late blight of caused by Phytophthora infestans (Mont.) de Bary has historically been serious disease of potatoes through worldwide, including India. Due to spatial variation in prevailing weather conditions, its severity varies from region to region. Disease development process and the weather parameters are well understood and have been utilized for disease developing forecasting models and decision support system. Therefore, an experiment was conducted for two consecutive cropping seasons (2017 & 2018) to develop a forecasting model against late blight of potato using stepwise regression analysis for Northern Himalayas in India. Maximum and minimum temperature, relative humidity, rainfall and wind speed appeared to be most significant factors in the potato late blight disease development. The meteorological conditions conducive for the development of potato late blight disease were characterized. Maximum and minimum temperatures in the range of 15.0 – 28.0°C and 2.0 – 12.0°C were found favorable for potato blight disease. Similarly, relative humidity, rainfall and wind speed in the range of 85 - 95 per cent, 15.5 - 20.75 mm and 1.0 - 5.5 Km h-1, respectively, were conducive for potato late blight disease which are helpful in disease development.

scholarly journals Masa Inkubasi Gejala Penyakit Hawar Daun Tanaman Kentang yang Diinduksi Ketahanannya oleh Jamur Antagonis Trichoderma viride

2016 ◽  
Vol 18 (2) ◽  
pp. 41
Author(s):  
Susiana Purwantisari ◽  
Achmadi Priyatmojo ◽  
Retno Peni Sancayaningsih ◽  
Rina Sri Kasiamdari
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Disease Incidence ◽  
Trichoderma Viride ◽  
Potato Late Blight ◽  
Biocontrol Agents ◽  
Trichoderma Spp ◽  
Late Blight Disease ◽  
Blight Disease

Late blight disease caused by Phytophthora infestans, is probably the single most important disease of potatoes worldwide. Infected plants were quickly killed and were difficult for replanting, causing significant losses for the growers. Various control methods were examined including the use of biocontrol agents of Trichoderma spp.  The biocontrol potential of Trichoderma viride against potato late blight pathogen, Phytophthora infestans, were studied  under greenhouse conditions. The research objective was to determine the ability of biocontrol agents Trichoderma viride to delay late blight disease incidence on potato plants in the field. The in vivo experiment was carried out at potato land area located at BALITSA in Cikole Sub District, Lembang District and Bandung Regency. Completely Randomized Design was used with six treatment and five replicates. The treatment tested consist of control (without pathogen fungal and antagonists fungus application too), control (with pathogen fungal application and without antagonist fungal application), chemical fungicide application, antagonist fungal application 2 weeks before planting, application 1 week after planting and both application 2 weeks before and 1 week after planting. Result of the research showed that application of antagonists fungal could delay disease intensity until 14 days. These antagonist could be used as biological agents initials to control leaf blight disease. Key words: Biological control, Potato late blight, Phytophthora infestans, Trichoderma viride

Evaluation of bio-agents and neem based products against late blight disease (Phytophthora infestans) of potato

2021 ◽  
Vol 74 (1) ◽  
pp. 181-187
Author(s):  
Mehi Lal ◽  
Sorabh Chaudhary ◽  
Sanjay Rawal ◽  
Sanjeev Sharma ◽  
Manoj Kumar ◽  
...  
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Late Blight Disease ◽  
Blight Disease

A laboratory study of vertical migration

1955 ◽  
Vol 144 (916) ◽  
pp. 329-354 ◽  
Keyword(s):  
Light Intensity ◽  
Vertical Migration ◽  
Time Course ◽  
Tap Water ◽  
Low Light ◽  
Overhead Light ◽  
Light Intensities ◽  
Orientation Response ◽  
Reduced Light ◽  
Characteristic Maximum

In a tank filled with a suspension of indian ink in tap water, a population of Daphnia magna will undergo a complete cycle of vertical migration when an overhead light source is cycli­cally varied in intensity. A ‘dawn rise’ to the surface at low intensity is followed by the descent of the animals to a characteristic maximum depth. The animals rise to the surface again as the light decreases, and finally show a typical midnight sinking. The light intensities at the level of the animals in this experiment are of the same order as those which have been reported in field observations; the time course of the movement also repeats the natural conditions in the field. The process is independent of the duration of the cycle and is related only to the variation in overhead light intensity. At low light intensity the movement of the animal is determined solely by positive photo-kinesis; the dawn rise is a manifestation of this, and is independent of the direction of the light. At high light intensities there is an orientation response which is superimposed upon an alternating positive (photokinetic) phase and a negative phase during which movement is inhibited. The fully oriented animal shows a special type of positive and negative phototaxis, moving towards the light at reduced light intensities and away from it when the light intensity is increased. In this condition it follows a zone of optimum light intensity with some exactness. Experiments show that an animal in this fully oriented condition will respond to the slow changes of intensity characteristic of the diurnal cycle, while being little affected by tran­sient changes of considerable magnitude.

Two new defensive constituents from potato tubers (Solanum tuberosum)

2017 ◽  
Vol 72 (6) ◽  
pp. 393-396
Author(s):  
Liangyan Liu ◽  
Jun Han ◽  
Yong Shen
Keyword(s):  
Solanum Tuberosum ◽  
Late Blight ◽  
Quantum Chemical ◽  
Spectroscopic Analysis ◽  
2D Nmr ◽  
Moderate Activity ◽  
Potato Tubers ◽  
Mycelia Growth ◽  
Late Blight Disease ◽  
Blight Disease

AbstractTwo new defensive constituents, solatuberenol A (1) and 3-O-β-d-glucopyranosyl stigmasta-5(6),24(28)-diene (2), were isolated from the potato tubers (Solanum tuberosum) infected with late blight disease. Their structures were identified by extensive spectroscopic analysis, including HRMS, IR, UV, 1D/2D NMR, ECD and quantum chemical calculations. Compounds 1 and 2 showed moderate activity against Phytophthora infestans with mycelia-growth inhibition of 30.1% and 52.4%, respectively, at the concentration of 500 ppm.

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