scholarly journals Influence of Meloidogyne incognita and Thielaviopsis basicola Populations on Early-Season Disease Development and Cotton Growth

Plant Disease ◽  
2000 ◽  
Vol 84 (4) ◽  
pp. 449-453 ◽  
Author(s):  
N. R. Walker ◽  
T. L. Kirkpatrick ◽  
C. S. Rothrock

Microplot studies were used to examine the effect of various population densities of Meloidogyne incognita and Thielaviopsis basicola on cotton-plant development and disease severity. Plots were infested with 0, 20, or 100 T. basicola chlamydospores/g and 0, 5, or 10 M. incognita eggs and juveniles/cm3 of soil in a factorial arrangement in 1997 and 1998. Combinations of M. incognita and T. basicola reduced plant survival in both years compared to the noninfested control, except in 1998 for the high rate of T. basicola over all nematode rates. Plant height-to-node ratios were reduced by pathogen combinations compared to the noninfested control or to either pathogen alone. Plant dry weight was reduced by M. incognita in 1998 and the high rate of T. basicola in 1997. Root necrosis was increased by increasing rates of T. basicola in 1997 and by M. incognita over all rates of T. basicola in both years. Colonization of root tissue by T. basicola was increased by the low inoculum density of the nematode at 20 CFU/g soil in 1997 and 100 CFU/g in 1998. Nematode reproduction with the high M. incognita treatment rate was reduced in both years of the study by the high T. basicola rate. This study suggests the importance of population level of each pathogen to the severity of disease and confirms the potential of this disease interaction to impact cotton production.

Nematology ◽  
2020 ◽  
Vol 22 (6) ◽  
pp. 667-676 ◽  
Author(s):  
Aminat Korede Akinsanya ◽  
Steve Olaoluwa Afolami ◽  
Peter Kulakow ◽  
Danny Coyne

Summary Despite being the single largest cassava-producing country, yields in Nigeria remain consistently poor and among the lowest. Regionally, yields are also particularly low across Africa. Pests and pathogens, including plant-parasitic nematodes, play an important role in this current yield deficit. African countries are not only faced with the problem of food security but also that of nutritional deficiency, due to limited micronutrients in the diet. In this study, six biofortified cultivars were evaluated for their response to inoculation with approximately 30 000 root-knot nematode (Meloidogyne incognita) eggs in 30 l pots in Nigeria. All cassava cultivars proved highly susceptible to M. incognita infection after 6 months, with nematode reproduction factor ranging from 7.0 to 44.8. Galling was common on feeder roots and gall index scores were recorded between 4 to 5 (on a scale of 1-5 where 5 ⩽ 100 galls). Meloidogyne incognita infection significantly reduced plant height, stem girth, fresh plant mass, fresh storage root number and storage root weight. Percentage yield loss of between 41.8-88.4% was recorded in M. incognita-infected plants compared with non-infected controls. Although M. incognita reduced storage root weight, it did not necessarily affect the nutritional quality (total carotenoid) or dry weight percentage of the biofortified cassava cultivars. Total carotenoid and dry weight contents of the control cultivar were similar to some of the biofortified cultivars. The high susceptibility of the biofortified cassava cultivars to M. incognita infection indicates that substantial yield losses are likely being experienced by farmers, as this nematode pest is prevalent across sub-Saharan Africa and the tropics.


2018 ◽  
Vol 11 (1) ◽  
pp. 9-18 ◽  
Author(s):  
T. Ansari ◽  
M. Asif ◽  
M.A. Siddiqui

SummaryThe root-knot nematodeMeloidogyne incognitais a major soil parasite of lentil crops. Increasing restrictions of chemical nematicides have triggered a growing attention and interest in alternate root-knot nematode management. The present study was conducted to examine the level of resistance and/or susceptibility of five lentil cultivars (PL-456, KLS-218, Desi, DPL-62, Malika), grown in pots, against the root-knot nematodeM. incognita. Root-knot nematode reproduction and host damage were assessed by recording the nematode infestation levels and reduction percentage of plant growth parameters. Nematode response and plant growth differentiated amongst the lentil cultivars. None of the cultivars was found immune or highly resistant. The cultivar Malika was found moderately resistant as it showed the lowest number of galls and egg masses/root as well as the lowest reduction of plant fresh weight (10.4%) and dry weight (6.9%). On the other hand, the cultivar Desi manifested the highest susceptibility exhibiting the highest number of galls and egg masses. There was a significantly negative correlation between the number of galls and plant growth parameters (plant fresh and dry weight and plant height).


2009 ◽  
Vol 52 (6) ◽  
pp. 1393-1400 ◽  
Author(s):  
Andréa Chaves ◽  
Elvira Maria Régis Pedrosa ◽  
Rejane Magalhães de Mendonça Pimentel ◽  
Rildo Sartori Barbosa Coelho ◽  
Lílian Margarete Paes Guimarães ◽  
...  

The effects of Coda Radimax (CR), Coda Humus-PK (CH) and Coda Vit (CV) on the induction of resistance for Meloidogyne incognita in sugarcane (Saccharum sp.) varieties (RB92579, RB863129, RB867515) through nematode reproduction, plant development and root anatomy analysis, emphasizing the differences of the lignin deposition, and cortex-vascular cylinder proportions were investigated. In 90 days after inoculation with eggs of M. incognita, CR reduced the number of eggs per root system in all the sugarcane varieties; CH and CV reduced eggs density in RB867515; CR increased stalk number in RB92579 and fresh weight of shoots in RB863129 and RB92579; CH increased plant height in RB92579 and fresh weight of shoots in RB92579 and RB867515, CV affected fresh weigh of shoots and roots of RB863129. All the tested compounds did not affect stalk diameter, number and dry weight of shoots. Cross-sections of roots showed no anatomical changes in the M. incognita inoculated tissues.


2014 ◽  
Vol 104 (5) ◽  
pp. 507-512 ◽  
Author(s):  
Jianbing Ma ◽  
Juan Jaraba ◽  
Terrence L. Kirkpatrick ◽  
Craig S. Rothrock

Effects of the root-knot nematode Meloidogyne incognita and the fungal pathogen Thielaviopsis basicola on cotton seedling growth and root morphology were evaluated in controlled environmental experiments. Four pathogen treatments, including noninfested soil, soil infested with M. incognita, soil infested with T. basicola, and soil infested with both pathogens were evaluated at soil bulk densities (BDs) of 1.25 and 1.50 g/cm3. Plant growth and the morphology of the root systems were evaluated 44 days after planting. Infestation with M. incognita and T. basicola together significantly reduced seedling emergence, number of stem nodes, and root system volume compared with either pathogen alone. Either M. incognita or T. basicola reduced plant height, root fresh weight, top dry weight; root parameters total root length, surface area, and links; and root topological parameters magnitude, altitude, and exterior path length. M. incognita infection increased root radius. Root colonization by T. basicola increased with the presence of M. incognita at the lower soil BD. In contrast to previous research with Pythium spp., root topological indices (TIs) were similar with all of the treatments. Root TIs were near 1.92, indicating a herringbone (less branching) root architectural structure. Studying root architecture using a topological model offers an additional approach to evaluating fungi and nematodes and their interactions for soilborne-pathogen systems.


2012 ◽  
pp. 58-65
Author(s):  
Duy Thai Truong ◽  
Van Dung Phan ◽  
Tu The Nguyen

Objective: Study on clinical characteristics and result of treatment benign vocal cord tumor with suspensive laryngeal endoscopic surgery. Materials and Methods: A prospective study was undertaken in 43 patients who had benign vocal cord tumor and performed a suspensive laryngeal endoscopic surgery at ENT Dept. of Hue University Hospital, from 3/2010 to 5/2011. Results: The most common was group was 31 - 45 (44.2%). There was no difference of gender. Moderate hoarness was 67.4%. Classification of benign laryngeal tumor: vocal nodules (13 cases), vocal cyst (18 cases), vocal polyp (10 cases) and Reinke’s edema (2 cases). The successful treatment rate of vocal benign tumor was 88.4%. Conclusions: Suspensive laryngeal endoscopic surgery was the best method to cure benign vocal cord tumor. The surgeon had a clear operative field, easy manoeuver, high rate of cure and less complication.


Plants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1145
Author(s):  
Ahmed Noureldeen ◽  
Mohd Asif ◽  
Taruba Ansari ◽  
Faryad Khan ◽  
Mohammad Shariq ◽  
...  

This study was conducted on tomato (Solanum lycopersicum cv. K-21) to investigate the bioprotective nature of Pseudomonas fluorescens and its interactive effects with Meloidogyne incognita in terms of growth biomarkers, changes in biochemical attributes and modulation in antioxidant enzymes of the tomato plant. In this study, we grew tomato plants with M. incognita and P. fluorescens in separate pots, simultaneously and sequentially (15 days prior or post) after 15 days of seed sowing. The sequential inoculation of Mi15→Pf maximally increased the root-knot index and decreased the nematode population. It was also noted that inoculation suppressed the plant growth biomarkers in comparison to control. However, maximum suppression in nematode reproduction and increment in growth and physiological attributes were observed when P. fluorescens was applied 15 days prior to the nematode (Pf15→Mi) as compared to control. All the treatments showed an increase in antioxidant enzymes. Expression of phenol content and defensive enzymes such as peroxidase (POX) and superoxide dismutase (SOD) increased, in contrast to a significant reduction in malondialdehyde (MDA) and hydrogen peroxide (H2O2) contents when compared with the untreated inoculated plants. However, the highest levels of POX and SOD, and a lowest of phenol, MDA and H2O2 were displayed in the treatment Pf15→Mi, followed by Mi+Pf and Mi15→Pf.


Nematology ◽  
2018 ◽  
Vol 20 (6) ◽  
pp. 525-537
Author(s):  
Chunjie Li ◽  
Jialin Wang ◽  
Jia You ◽  
Xinpeng Wang ◽  
Baohui Liu ◽  
...  

Summary A recombinant inbred line population of soybean (Glycine max) was utilised to identify the quantitative trait loci (QTLs) determining the response to infection by two root-knot nematode species, Meloidogyne incognita and M. hapla, in glasshouse assays. QTL analysis detected seven major and four minor QTLs on seven soybean chromosomes ((Chrs) 1, 7, 8, 10, 14, 18, 20) explaining 6-41% phenotypic variance (PVE) for M. incognita root response and nematode reproduction. Three of the major QTLs, on Chrs 7, 10 and 18, were confirmed in previous reports and two major QTLs on Chrs 14 and 20 were detected for the first time. The QTL analysis with M. hapla provides the first report of a major QTL region mapped on Chr 7, explaining 70-82% PVE in M. hapla root response and nematode reproduction. These novel identified QTLs with flanking markers will be helpful in marker-assisted breeding for nematode resistance in soybean.


2012 ◽  
Vol 30 (1) ◽  
pp. 28-34
Author(s):  
Frank P. Henning ◽  
Timothy J. Smalley ◽  
Orville M. Lindstrom ◽  
John M. Ruter

We investigated the influences of fall fertilization and light intensity on photosynthesis and freeze resistance of Rhododendron ×kurume ‘Pink Pearl’, an evergreen azalea cultivar, grown outdoors in containers under nursery conditions. The study included two main-plot fall fertilization treatments: 1) 0.5 liter solution containing 75 mg·liter−1 N applied for 60 days from August 1 through September 29 and 2) 0.5 liter solution containing 125 mg·liter−1 N applied for 120 days from August 1 through November 28, and four subplot light intensity treatments 1) 100% ambient photon flux density (PPFD) from May 1, 2004, through May 1, 2005, 2) shade fabric rated to reduce PPFD by 50% from May 1 through September 30, 2004, followed by 100% PPFD from October 1, 2004, through May 1, 2005, 3) 100% PPFD from May 1 through September 30, 2004, followed by 50% PPFD from October 1, 2004, through May 1, 2005, and 4) 50% PPFD from May 1, 2004, through May 1, 2005. Fertilizer application and shade treatments did not interact in their effects on stem freeze resistance or the timing of anthesis. The high rate of extended fertigation (125 mg·liter−1 N applied August 1 through September 28) reduced freeze resistance of azalea stems and advanced anthesis by 4.9 days compared to plants that received moderate fertigation (75 mg·liter−1 N from August 1 through September 29). The high rate of extended fall fertigation failed to increase leaf or stem dry weight compared to plants that received the moderate rate of fertigation. Plants grown in 50% PPFD from May 1 through September 30 produced 163% more above ground dry weight compared to plants grown in 100% light during the same time period. The addition or removal of shade cloth beginning October 1 failed to enhance azalea stem freeze resistance compared to plants that were only exposed to 100 or 50% PPFD respectively. Shade treatments affected the chlorophyll fluorescence ratio (Fv · Fm−1) of leaves, but leaf fluorescence was unrelated to stem freeze resistance. Shade treatments affected azalea growth and photosynthetic stress, but shade neither interacted with fall fertilization to increase stem freeze resistance, nor had a biologically significant effect on stem freeze resistance.


2021 ◽  
pp. sextrans-2021-055220
Author(s):  
Ben B Hui ◽  
Jane S Hocking ◽  
Sabine Braat ◽  
Basil Donovan ◽  
Christopher K Fairley ◽  
...  

BackgroundThe Australian Chlamydia Control Effectiveness Pilot (ACCEPt) was a cluster randomised controlled trial designed to assess the effectiveness of annual chlamydia testing through general practice in Australia. The trial showed that testing rates increased among sexually active men and women aged 16–29 years, but after 3 years the estimated chlamydia prevalence did not differ between intervention and control communities. We developed a mathematical model to estimate the potential longer-term impact of chlamydia testing on prevalence in the general population.MethodsWe developed an individual-based model to simulate the transmission of Chlamydia trachomatis in a heterosexual population, calibrated to ACCEPt data. A proportion of the modelled population were tested for chlamydia and treated annually at coverage achieved in the control and intervention arms of ACCEPt. We estimated the reduction in chlamydia prevalence achieved by increasing retesting and by treating the partners of infected individuals up to 9 years after introduction of the intervention.ResultsIncreasing the testing coverage in the general Australian heterosexual population to the level achieved in the ACCEPt intervention arm resulted in reduction in the population-level prevalence of chlamydia from 4.6% to 2.7% in those aged 16–29 years old after 10 years (a relative reduction of 41%). The prevalence reduces to 2.2% if the proportion retested within 4 months of treatment is doubled from the rate achieved in the ACCEPt intervention arm (a relative reduction of 52%), and to 1.9% if the partner treatment rate is increased from 30%, as assumed in the base case, to 50% (a relative reduction of 59%).ConclusionA reduction in C. trachomatis prevalence could be achieved if the level of testing as observed in the ACCEPt intervention arm can be maintained at a population level. More substantial reductions can be achieved with intensified case management comprising retesting of those treated and treatment of partners of infected individuals.


2009 ◽  
Vol 44 (12) ◽  
pp. 1673-1681 ◽  
Author(s):  
Sebahattin Çürük ◽  
H. Yıldız Dasgan ◽  
Sedat Mansuroğlu ◽  
Şener Kurt ◽  
Meltem Mazmanoğlu ◽  
...  

The objective of this work was to evaluate the effect of grafting (onto Solanum torvum Sw.) on plant growth, yield and fruit quality of the Pala and Faselis eggplant (Solanum melongena L.) cultivars, grown in a soil infested with Verticillium dahliae Kleb. and Meloidogyne incognita, or in noninfested soil. Soil infestation decreased yield, plant height, final above-ground biomass, and also reduced fruit mean weight and shoot dry weight depending on cultivar or grafting. Grafting decreased fruit oxalic acid and the soluble solid contents, and increased mean fruit weight, depending on cultivar and soil infestation. Grafting also reduced the negative effects of the pathogens on disease index, plant height and shoot dry weight. Cultivar Pala was more vigorous than Faselis, and S. torvum was a vigorous rootstock. The combination of a vigorous rootstock with a weak cultivar (Faselis) is more profitable than that of a vigorous rootstock and a vigorous cultivar (Pala). Using S. torvum as a rootstock for cultivar Faselis, grown in soil infested with the pathogens, is most likely to be useful in conventional and low-input sustainable horticulture, since grafting increases protection against the pathogens, and reduces the losses in quality and yield.


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