scholarly journals Screening of Tuberose Cultivars against Leaf Spot (Alternaria polyanthi) and its Management

Author(s):  
N. Mazumder ◽  
S.K. Borah ◽  
K.K. Deka

Background: Tuberose flower has been found to be affected by various fungal and viral diseases which affect growth and cause loss in flower yield. Among them, leaf spot incited by Aternaria polianthi is an important fungal disease in tuberose. The incidence of the disease is common in the both single and double-type tuberose varieties due to prevalence of high rainfall and humid conditions. During survey it was found that the disease incidence was increasing gradually causing economic losses in Assam. Methods: The field trial was carried out during kharif seasons (2015 -18) to test the efficacy of six fungicides against leaf spot of tuberose (Var. Local single petal) caused by Alternaria polyantha. Four sprays with fungicides at an interval of seven days starting from the first appearance of the disease symptom were done. Per cent disease incidence (%) with growth parameters were recorded one week after the last spray. Another field experiment for screening the resistant genotypes was conducted using 11 tuberose genotypes during kharif seasons (2016-17 and 2017-18). Result: Eleven tuberose cultivars (Bidhan Ranjani-1, Bidhan Ranjani-2, Arka Nirantara, GK-TC-4, Prajwal, Phule Rajani, Local Single, Local Double, Vaibhav, Suhashini and Shringer) were screened against leaf spot caused by A.polyanthi under natural field condition. None of the cultivars were found to be immune or resistant, while three cultivars viz., GK-TC-4, Bidhan Rajani-1 and Arka Nirantara showed moderate resistant reaction with recorded per cent disease incidence of 16.11, 18.17 and 18.71, respectively. Spraying with azoxystrobin, difenoconazole and a combo fungicide consisting of iprodione (25%) + carbendazim (25%), at 0.1% recorded lowest per cent disease incidence of 7.91, 9.83 and 11.85% compared to control (33.62 PDI) with per cent disease reduction of 70.59%, 64.61% and 76.31%, respectively.

Author(s):  
Sabiya Bashir ◽  
Mohammad Najeeb Mughal ◽  
Zahida Rashid ◽  
Shabeena Majid ◽  
Sabeena Naseer ◽  
...  

Sixty-three genotypes of  french bean was screened against leaf spot (Alternaria  alternata) in sick plots at Research Farm of Dryland Agriculture Research Srinagar, Rangreth during  Kharif  2018 and 2019. The highest mean disease incidence ranged from 0.00 to 85.00 per cent  with  the mean disease intensity ranged from 0.00 to 53.26 per cent .One genotype namely  ‘Local Pulwama’ was highly susceptible in their disease reaction. Among the screened germplasm, ‘Highly Resistant’ genotypes was SKU-R-601, SKUA-R-105, SKU-R-927, DARS-25, DARS-66, DARS-R-615,  while as ‘Susceptible’ genotypes was  DARS-8, DARS-12,  DARS-11, SKUAST-R-155, SKU-R-928, DARS-7, DARS-R-4, Bhaderwah (L),  Local  Kupwara black and Raj Jawala. Local Pulwama was found to be a highly susceptible (HS) genotype.  Twenty nine genotypes namely., DARS-16, DARS-9, DARS-54, DARS-39, VL-125, DARS-63, ENTO-504, SKUAST-204,SKU-R-925, DARS-60, DARS-109, DARS-43, DARS-44, SKU-R-23, DARS-4, DARS-74, SKU-R-105, DARS-40, DARS-23, DARS-18, SKU-R-71, WB-341, SKU-R-605, Uri local, Shopian (L), SKU-R-23, DARS-71, SSGB-729, DARS-R-19 showed resistant reaction to disease. The selection for resistance was based on the reaction of varieties on leaves.


2013 ◽  
Vol 38 (3) ◽  
pp. 491-503 ◽  
Author(s):  
MH Hossain ◽  
I Hossain

A study was undertaken to evaluate effectiveness of foliar spray with 33 plant extracts against leaf spot (Tikka) of groundnut caused by Cercospora arachidicola and Cercosporidium personatum. Bavistin and BAU-Biofungicide were included in the experiment as checks and spray of plain water represented control. Almost all treatments gave considerable reduction in disease incidence and increase in growth parameters, pod and haulm yield compared to control. The most effective materials were Bavistin 50 WP, BAU-Biofungicide, leaf extract of neem, tomato, datura black, and datura white. The materials decreased spot number per leaf, defoliation per plant, incidence of leaf spot, and number of infected leaf per plant by 35.45 -60.07, 42.06-72.20, 51.97–63.58, and 38.33 to 46.89 % and increased pod yield and haulm yield by 64.37-111.41 and 32.35- 74.71 %, respectively. The materials may be recommended against the disease after economic analysis. DOI: http://dx.doi.org/10.3329/bjar.v38i3.16976 Bangladesh J. Agril. Res. 38(3): 491-503, September 2013


2021 ◽  
Vol 4 (2) ◽  
pp. 148-154
Author(s):  
Kapil Paudel ◽  
Naresh Dangi ◽  
Anisur Rahman Ansari ◽  
Rashmi Regmi

Fourty sugarcane genotypes with different period of maturity were evaluated against top borer (Scirpophaga excerptalis Walker) infestation under natural field condition during 2018 and 2019 at National Sugarcane Research Program, Jeetpur, Nepal. The experiment was conducted in alpha-lattice design under natural condition of infestation using Co 0238 as susceptible check. Based on the incidence, 26 genotypes were categorized as less susceptible, eleven genotypes were found moderately susceptible to S. excerptalis. However, among less susceptible genotypes lowest incidence of 3.11 percent was recorded in genotype CoS 8432. Whereas, highest incidence of 25.24 percent was recorded in highly susceptible genotype, CoSe 98255BD 24. Most of the cane genotypes were found low to moderately susceptible, having 5 to 20% incidence of the pest. Whereas, some of the varieties, namely CoH 160 (21.22%), CoSe 95255 BD 24 (25.24%) and BO 150 (22.02%) were found highly susceptible. The mechanism responsible for host plant resistance against top borer is not studied in this experimentation. The study in these aspects is to be conducted to explore the mechanisms of host plant resistance for using these resistant genotypes for breeding purpose.


2019 ◽  
Vol 11 (3) ◽  
pp. 440-446
Author(s):  
Bolaji Zuluqurineen SALIHU ◽  
Mathew Omoniyi ADEBOLA ◽  
Maryam Alfa KABARAINI ◽  
Sunkanmi Tokunbo GBADEYAN ◽  
Adijat Abolore AJADI ◽  
...  

Fungal diseases cause a lot of economic damage in castor and in some instances; it is a limiting factor to commercial cultivation of the crop. In the present study, survey on castor germplasm for sources of resistant genes to Cercospora leaf spot was carried out at National Cereals Research Institute Badeggi, Nigeria. The genotypes were grown in a resolvable incomplete block design with three replications. The results obtained revealed high variability of host resistance among the genotypes. Percentage disease incidence ranged between 16.67% and 100%.  A range between 1.43 score and 4.17 scores with average score of 2.89 were recorded for disease severity among the genotypes. Highest (95.92%) and lowest (13.03%) damage index were observed in the genotypes Acc. 059 and Acc. 022 respectively. The Principal component (PC) 1 to 4 explained 100% of the variability in the germplasm. PC1 explained 69.72% of the variability with the major contributory parameters being the disease incidence, severity and damage index. Significant negative correlations were recorded between the seed yield and all the three disease indices. The result of cluster analysis revealed six cluster groups among the germplasm with cluster membership ranging between 4 and 40 members. The cluster I contained members (Acc. 002, Acc. 017, Acc. 022, Acc. 026, Acc. 027, Acc. 048 and Acc. 061) with low average disease incidence, severity and damage index. The results reported here could serve as a basis for further screening of the potential resistant genotypes under controlled condition to develop resistant lines.


Author(s):  
N. Mazumder ◽  
S. K. Borah ◽  
Preeti Hatibarua

Six fungicides viz., mancozeb 75 WP @ 0.2%, chlorothalonil 75% WP @ 0.2% , tricyclazole 75% WP @ 0.1%, iprodione 25% + carbendazim 25% WP @ 0.1% , difenconazole 25% EC @ 0.1%, azoxystrobin 23 SC @ 0.1% were evaluated for managing leaf spot (Alternaria polianthi) of tuberose (Polianthes tuberosa L.) cv. Single Petal with during kharif, 2010-2013. Four sprays with azoxystrobin (0.1%) at 15 days interval, starting on disease appearance proved to be the most effective and resulted in the lowest disease incidence (10.98 PDI ) compared to control ( 34.39 PDI ). This treatment also gave a fairly good benefit: cost (B: C) ratio of 6.87. The economic analysis, however, revealed the effectiveness of a combo fungicide, iprodion (25%) + carbendazim (25%), followed by difenconazole when they were applied at 0.1% concentration. These treatments recorded highest B:C ratio of 7.11 and 6.90 with 69.98% and 71.47% disease reduction, respectively.


2016 ◽  
Vol 30 (1) ◽  
pp. 55
Author(s):  
C. F. Gleena Mary ◽  
Sally K. Mathew

Bacterial wilt is one of the most dreaded diseases in tomato growing areas all over the world. Though chemical control measures and resistance breeding offers certain degree of protection against wilt pathogen, both have their own limitations such as high cost, environmental impact, non target effect and development of resistance. Hence, biologically safe methods such as use of composts as soil amendments for wilt management was investigated in the present study which revealed the possibility of the use of ligno-phenolic composts in disease management. Among the five composts tested, application of ayurvedic compost at 45 days after planting was found to be the most effective with lowest wilt incidence of 6.94 per cent against 36.10 per cent in control, with 80.77 per cent disease reduction. At 60 DAP, same trend was noticed with minimum disease incidence in ayurvedic compost (13.88 %) which was on par with full basal application of leaf litter compost (15.27 %), and coir pith compost (16.66 %) with 86.79 to 60.02 per cent reduction of wilt incidence. In case of yield, among the different composts, split and basal application of ayurvedic compost recorded highest yield of 8.9 kg/6.48 m<sup>2</sup>.


2016 ◽  
Vol 50 (1) ◽  
Author(s):  
Y. V. Ingle ◽  
G. D. Chandankar ◽  
P. V. Patil ◽  
C. U. Patil

Root rot/Charcoal rot, <italic>Alternaia</italic> leaf spot, Bacterial pustule and Yellow Mosaic Virus are important one disease in Vidarbha region of Maharashtra. Thirty advance lines of soybean were screened for these diseases in protected and un-protected condition under natural field conditions and results revealed that four entries viz.NRC-94, JS-20-69, JS 20-71 and KDS- 699 were shown Resistant High Yield (R-HY) reaction to disease complex while NRC-92, KDS 705, KDS-378 and JS 20-41 exhibit Susceptible High Yield Tolerance (S-HY (T)) reaction to disease complex. Only one entry (SL-958) initiates Resistant Low Yield (R-LY) reaction. Rest of the tested advance lines showed Susceptible Low Yield (S-LY) reaction.


Plant Disease ◽  
2021 ◽  
Author(s):  
Zeng-Liang LIU ◽  
Shuangyun Zhou ◽  
Liangliang Qi ◽  
Xiaoguo Wang ◽  
Juan Song ◽  
...  

Ginger (Zingiber officinale Rosc.) is an herbal crop widely grown in China for its medicinal and savory qualities of rhizomes. In August 2018, leaf spot symptoms were observed on ginger plants grown in a field in Nanning, Guangxi Province (E108°3'54", N23°14'48"). Disease incidence was above 50%, and in a Nanning field, rhizome yield loss was almost 30%. Early symptoms appeared as circular, necrotic areas that later developed into circular or irregular spots. The centers of the lesions were white and often surrounded by chlorotic halos (Figure S1A). In severe infections, the spots frequently coalesced, causing the entire leaf to become withered and curved. Small pieces (3 to 4 mm2) from the margin of infected lesions were surface sterilized in 75% ethanol for 40 s followed by 1% NaOCl for 90 s, placed on potato dextrose agar (PDA) and incubated at 28°C in the dark for 4 days. Hyphal tips from the leading edge of colonies were transferred to fresh PDA plates to obtain pure cultures. Fungal colonies were initially white, then turned black/grayish brown when maintained in the dark at 28°C after 5 days (Figure S1B). Conidia were single-celled, brown, or black, smooth, spherical, or subspherical with diameters varying from 9.5 to 15 μm (mean = 13.5 ± 0.72 µm, n = 50) (Figure S1C). Based on these morphological characteristics, the isolates were provisionally identified as Nigrospora oryzae (Ellis 1971; Hudson 1963). Genomic DNA was extracted from a representative isolate Sjb-2. The internal transcribed spacer (ITS) region, beta-tubulin (TUB2), and the translation elongation factor 1-alpha (TEF1-α) were amplified using primer pairs including ITS1/ITS4 (White et al. 1990), Bt-2a/Bt-2b (Glass and Donaldson 1995), and EF1-728F/EF1-986R (Carbone et al. 1999), respectively. The obtained ITS sequence (GenBank accession no. MW555242), TUB2 sequence (MZ048644), and TEF1-α sequence (MZ048645) showed >99% similarity with several GenBank sequences of N. oryzae (KF516962 for ITS; MK550707 for TUB2; and KY019425 for TEF1-α, respectively). Based on the combined sequences of ITS, TUB2 and TEF1-α sequences, a phylogenetic tree was constructed using the maximum likelihood method and confirmed that the isolates were N. oryzae (Figure S2). Pathogenicity of the isolate was confirmed by fulfilling Koch’s postulates. Agar blocks (3 mm diameter) containing a fungal mycelium were placed on detached healthy leaves of ginger. The leaves were then wrapped with sterile polyethylene and incubated in a greenhouse at 25°C with 60% RH. Within 7 days, symptoms appeared on inoculated leaves similar to spots observed in the field, whereas controls remained symptomless. The same pathogen was reisolated from the spots. Pathogenicity tests were performed twice with three replications, indicating that N. oryzae is responsible for leaf spot disease on ginger. The disease in ginger caused by N. oryzae had been reported in Southern Africa (Grech et al. 1989). To our knowledge, this is the first report of N. oryzae causing leaf spot of ginger in China. In the field, this pathogen can substantially affect ginger's health and rhizome yield if no effective control measures are implemented. Therefore, management of the disease should be further investigated to avoid major economic losses.


2020 ◽  
Vol 13 (2) ◽  
pp. 83-92 ◽  
Author(s):  
A. Adam

SummaryEnhancement of the resistance level in plants by rhizobacteria has been proven in several pathosystems. This study investigated the ability of four rhizobacteria strains (Pseudomonas putida BTP1 and Bacillus subtilis Bs2500, Bs2504 and Bs2508) to promote the growth in three barley genotypes and protect them against Cochliobolus sativus. Our results demonstrated that all tested rhizobacteria strains had a protective effect on barley genotypes Arabi Abiad, Banteng and WI2291. However, P. putida BTP1 and B. subtilis Bs2508 strains were the most effective as they reduced disease incidence by 53 and 38% (mean effect), respectively. On the other hand, there were significant differences among the rhizobacteria-treated genotypes on plant growth parameters, such as wet weight, dry weight, plant height and number of leaves. Pseudomonas putida BTP1 strain was the most effective as it significantly increased plant growth by 15-32%. In addition, the susceptible genotypes Arabi Abiad and WI2291 were the most responsive to rhizobacteria. This means that these genotypes have a high potential for increase of their resistance against the pathogen and enhancement of plant growth after the application of rhizobacteria. Consequently, barley seed treatment with the tested rhizobacteria could be considered as an effective biocontrol method against C. sativus.


Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 373
Author(s):  
Siti Fairuz Yusoff ◽  
Farah Farhanah Haron ◽  
Norhayu Asib ◽  
Mahmud Tengku Muda Mohamed ◽  
Siti Izera Ismail

Postharvest fruits including tomatoes are commonly infected by gray mold disease resulting in significant economic losses in the fruit industry. Therefore, this study aimed to develop botanical fungicide derived from Vernonia amygdalina leaf extract to control gray mold on tomato. The emulsion formulation containing surfactant, oil carrier and water was optimized at different non-ionic alkyl polyglucoside surfactants through eleven combinations of oil to surfactant ratio (0:10, 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2, 9:1 and 10:0 w/w). From eight selected formulations, two formulations, F5 and F7 showed stable in storage, remarkable thermodynamic stability, smaller particle size (66.44 and 139.63 nm), highly stable in zeta potential (−32.70 and −31.70 mV), low in polydispersity index (0.41 and 0.40 PdI), low in viscosity (4.20 and 4.37 cP) and low in surface tension (27.62 and 26.41 mN/m) as compared to other formulations. In situ antifungal activity on tomato fruits showed F5 formulation had a fungicidal activity against B. cinerea with zero disease incidence and severity, whereas F7 formulation reduced 62.5% disease incidence compared to a positive control with scale 1. Based on these findings, F5 formulation exhibited pronounced antifungal activity and may contribute to the development of new and safe antifungal product against gray mold on tomato.


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