scholarly journals Salicylic Acid and Pseudomonas fluorescens as Safe Control Means Against Rhizoctonia solani in Guar (Cyamopsis tetragonoloba (L.) Taub.)

2016 ◽  
Vol 44 (1) ◽  
pp. 25-47
Author(s):  
Montasser Abdel-Monaim
2017 ◽  
Vol 6 (1) ◽  
pp. 01-15
Author(s):  
Montaser F. Abdel-Monaim

Rhizoctonia solani was found to be associated with root rot symptoms of guar plants collected from different fields in New Valley governorate, Egypt. All the obtained isolates were able to attack guar plants (cv. Local) causing damping-off and root rot diseases. R. solani isolates No. 8 (RG8) was the more virulent ones in the pathogenicity tests. Salicylic acid (SA) and Pseudomonas fluorescens (PF) individually or in combination were examined for their potential in suppression damping-off and root rot and growth promotion of guar plants in vitro and in vivo. Both SA and P. fluorescens either individually or in combination inhibited the growth of the tested pathogenic fungi.SA combined with P. fluorescens recorded the highest inhibited growth followed by P. fluorescens alone. Under greenhouse and field conditions, all treatments significantly reduced damping-off and root rot severity. The combination of SA and P. fluorescens was more effective than using them individually.  Under field conditions, all these treatments significantly increased growth parameters (plant height and No. of branches plant-1) and yield components (No. of pods plant-1, weight of 100 seeds and total yield fed.-1 and Guaran content (gm plant-1) in both locations (El-Kharga and Mallawy Agric. Res. Stations) during growing season 2014.The combination of SA and P. fluorescens were recorded the highest growth parameters and yield components. Generally, the combination of SA and P. fluorescens recorded the best results for controlling damping-off and root rot diseases in greenhouse and field with addition improved plant growth and increased yield components in the field. In physiological studies, activity of defense-related enzymes, including peroxidase (PO), polyphenol oxidase (PPO), phenylalanine ammonia lyase (PAL), pathogenesis related (PR) protein (chitinase and β 1,3 gluconase), were increased in inoculated and non-inoculated plants treated with the SA and P. fluorescens either individually or in combination, during the experimental period. The combination of SA and P. fluorescens recorded the highest increase in activity of all enzymes.  In general, the activity of these enzymes begins to accumulate after two days of treatment and reached maximum levels at 6 to 10 days, then the activities of these enzymes were decreased progressively. On the other hand, total phenols and lignin increased in guar plants inoculated with R. solani and treated with SA and P. fluorescens individually or in combination. The highest accumulation of phenols was recorded 8th days from application, while lignin recorded the highest level at 10th days from application. In the end, these results suggested that SA and P. fluorescens either individually or in combination may play an important role in controlling the guar damping-off and root rot diseases, though they have induction of systemic resistance in guar plants.


2020 ◽  
Vol 16 (1) ◽  
pp. 37-48
Author(s):  
Ratna Sari Dewi ◽  
Giyanto Giyanto ◽  
Meity Suradji Sinaga ◽  
Dadang Dadang ◽  
Bambang Nuryanto

Saat ini teknologi pengendalian hayati penyakit utama padi terus berkembang. Dalam pengembangan teknologi pengendalian hayati, mekanisme penghambatan patogen dalam perkembangan penyakit pada suatu populasi tumbuhan dalam area tertentu menjadi hal yang penting. Penelitian bertujuan mendapatkan bakteri agens hayati potensial dalam pengendalian penyakit penting padi di antaranya yang disebabkan Pyricularia oryzae, Xanthomnas oryzae pv. oryzae, Rhizoctonia solani, Burkholderia glumae, dan Drechlera oryzae, berdasarkan mekanisme antagonisme, kemampuan menginduksi ketahanan dan mendukung kebugaran tanaman, serta kompatibilitas antaragens hayati. Ralstonia pickettii TT47, Pseudomonas fluorescens P12, Chromobacterium sp. T51118, Bacillus subtilis 451 dan 154, serta Streptomyces sp. T51105 dibuktikan memiliki mekanisme antibiosis dengan menghasilkan metabolit sekunder dan senyawa volatil. Berdasarkan uji produksi enzim kitinolitik Chromobacterium sp. dan Streptomyces sp. memiliki mekanisme lisis. Aktivitas antibiotik R. pickettii dan P. fluorescens tergolong kuat terhadap P. oryzae dengan penekanan secara berurutan sebesar 79.68% dan 77.59% pada uji biakan ganda. Penekanan pertumbuhan miselium P. oryzae dan R. solani pada uji volatil mencapai 100% oleh Chromobacterium sp. Semua agens hayati umumnya mampu menginduksi ketahanan dan mendukung kebugaran tanaman. Uji kompatibilitas menunjukan R. pickettii, P. fluorescens, dan Chromobacterium sp. bersifat kompatibel. Dari hasil penelitian diperoleh tiga bakteri agens hayati dengan kategori unggul, yaitu P. fluorescens P12, R. pickettii TT47, dan Chromobacterium sp. T51118. Ketiganya mampu menekan pertumbuhan patogen, menginduksi ketahanan dan mendukung kebugaran tanaman, memiliki patogen sasaran yang lebih beragam, serta bersifat kompatibel.


2005 ◽  
Vol 51 (4) ◽  
pp. 345-353 ◽  
Author(s):  
Rita Grosch ◽  
Franziska Faltin ◽  
Jana Lottmann ◽  
A Kofoet ◽  
Gabriele Berg

Rhizoctonia solani causes yield losses in numerous economically important European crops. To develop a biocontrol strategy, 3 potato-associated ecto- and endophytically living bacterial strains Pseudomonas fluorescens B1, Pseudomonas fluorescens B2, and Serratia plymuthica B4 were evaluated against R. solani in potato and in lettuce. The disease-suppression effect of the 3 biocontrol agents (BCAs) was tested in a growth chamber and in the field. In growth chamber experiments, all 3 BCAs completely or significantly limited the dry mass (DM) losses on lettuce and the disease severity (DS) caused by R. solani on potato sprouts. Strain B1 showed the highest suppression effect (52% on average) on potato. Under field conditions, the DS on both crops, which were bacterized, decreased significantly, and the biomass losses on lettuce decreased significantly as well. The greatest disease-suppression effect on potato was achieved by strain B1 (37%), followed by B2 (33%) and then B4 (31%), whereas the marketable tuber yield increased up to 12% (B1), 6% (B2), and 17% (B4) compared with the pathogen control at higher disease pressure. Furthermore, in all experiments, B1 proved to be the most effective BCA against R. solani. Therefore, this BCA could be a candidate for developing a commercial product against Rhizoctonia diseases. To our knowledge, this is the first report on the high potential of endophytes to be used as a biological control agent against R. solani under field conditions.Key words: biocontrol, Rhizoctonia solani, field grown lettuce and potato, antagonistic bacteria, endophytes.


2021 ◽  
Author(s):  
Chandra Prakash Nama ◽  
B.L. Baheti

Abstract AimThe experiment was carried out during two consecutive Kharif seasons to test the combined efficacy of biochemicals i.e. salicylic acid, ascorbic acid and L-arginine each at 2 % w/w as seed treatment and botanicals viz. neem, lantana and parthenium leaves powder each at 5 g per plant for the management of root-knot nematode, Meloidogyne incognita infecting cluster bean..Method All treatments applied as soil application at the time of sowing. Before sowing observation on initial nematode population/100 cc soil and at the termination of experiment number of galls/plant, number of egg masses/plant, number of eggs and larvae/egg mass, final nematode population/100 cc soil and yield (q/ha) were recorded. ResultAmong different combinations, minimum nematode population were observed with ascorbic acid at 2 per cent w/w + neem leaves powder at 5 g per plant followed by ascorbic acid at 2 per cent + lantana leaves powder at 5 g per plant and salicylic acid at 2 per cent + neem leaves powder at 5 g per plant.Conclusion: Results of experiment showed that application of biochemicals along with botanicals significantly reduced galls per plant as compared to untreated check.


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