scholarly journals Effects of Cultural Practices and Temperature on Fusarium Root and Crown Rot of Container-Grown Hostas

Plant Disease ◽  
2002 ◽  
Vol 86 (3) ◽  
pp. 225-231 ◽  
Author(s):  
B. Wang ◽  
S. N. Jeffers
Keyword(s):  
Cultural Practices ◽  
Crown Rot ◽  
Pine Bark ◽  
Disease Development ◽  
Disease Symptoms ◽  
Integrated Strategy ◽  
Different Temperatures ◽  
Conidium Suspension ◽  
Root And Crown Rot ◽  
The Impact

Fusarium root and crown rot of hosta plants grown in containers is caused primarily by Fusarium hostae. In an effort to develop an integrated strategy for managing this disease at nurseries, the effects of wounding, container mix content, watering schedule, and temperature on disease development were investigated. Plants were not wounded or were wounded by severing the roots, severing the roots and making incisions in the crown, or severing the roots and removing a small piece of the crown. Plants were inoculated by dipping roots and crowns into a suspension of conidia from one of two isolates of F. hostae. In addition, some plants were inoculated by wounding crowns with a scalpel dipped in a conidium suspension. Disease development was examined on plants grown at different temperatures (18, 25, or 32°C), grown in different container mixes (100% Canadian sphagnum peat, 100% aged and processed pine bark, or a mixture of 50% peat and 50% bark), and watered on different schedules (which kept the container mix wet, moist, or dry). Significant levels of disease occurred only on plants that were wounded when inoculated. Fusarium root and crown rot was more severe when both the roots and crowns were wounded than when only the roots were wounded. Disease symptoms developed when crowns of plants were wounded with a scalpel infested with conidia, suggesting that contaminated tools used for vegetative propagation may transfer F. hostae. Disease development also was affected significantly by container mix content, watering schedule, and temperature. In separate experiments, disease was most severe on plants grown in 100% aged pine bark, in dry container mix, or at 18 to 25°C. Disease development was significantly less when plants were grown in 100% peat, in wet container mix, or at 32°C. These results suggest that altering or manipulating cultural practices used to produce hostas in containers at nurseries can reduce the impact from Fusarium root and crown rot.

scholarly journals Temperature, Moisture, and Fungicide Effects in Managing Rhizoctonia Root and Crown Rot of Sugar Beet

2010 ◽  
Vol 100 (7) ◽  
pp. 689-697 ◽  
Author(s):  
Melvin D. Bolton ◽  
Lee Panella ◽  
Larry Campbell ◽  
Mohamed F. R. Khan
Keyword(s):  
Sugar Beet ◽  
Disease Incidence ◽  
Environmental Parameters ◽  
Disease Suppression ◽  
Crown Rot ◽  
Disease Development ◽  
Water Control ◽  
Disease Symptoms ◽  
Root And Crown Rot ◽  
Growth Chambers

Rhizoctonia solani AG-2-2 is the causal agent of Rhizoctonia root and crown rot in sugar beet; however, recent increases in disease incidence and severity were grounds to reevaluate this pathosystem. To assess the capacity at which other anastomosis groups (AGs) are able to infect sugar beet, 15 AGs and intraspecific groups (ISGs) were tested for pathogenicity on resistant (‘FC708 CMS’) and susceptible (‘Monohikari’) seedlings and 10-week-old plants. Several AGs and ISGs were pathogenic on seedlings regardless of host resistance but only AG-2-2 IIIB and AG-2-2 IV caused significant disease on 10-week-old plants. Because fungicides need to be applied prior to infection for effective disease control, temperature and moisture parameters were assessed to identify potential thresholds that limit infection. Root and leaf disease indices were used to evaluate disease progression of AG-2-2 IIIB- and AG-2-2 IV-inoculated plants in controlled climate conditions of 7 to 22 growing degree days (GDDs) per day. Root disease ratings were positively correlated with increasing temperature of both ISGs, with maximum disease symptoms occurring at 22 GDDs/day. No disease symptoms were evident from either ISG at 10 GDDs/day but disease symptoms did occur in plants grown in growth chambers set to 11 GDDs/day. Using growth chambers adjusted to 22 GDDs/day, disease was evaluated at 25, 50, 75, and 100% moisture-holding capacity (MHC). Disease symptoms for each ISG were highest in soils with 75 and 100% MHC but disease still occurred at 25% MHC. Isolates were tested for their ability to cause disease at 1, 4, and 8 cm from the plant hypocotyl. Only AG-2-2 IIIB was able to cause disease symptoms at 8 cm during the evaluation period. In all experiments, isolates of AG-2-2 IIIB were found to be more aggressive than AG-2-2 IV. Using environmental parameters that we identified as the most conducive to disease development, azoxystrobin, prothioconazole, pyraclostrobin, difenoconazole/propiconazole, flutolanil, polyoxin D, and a water control were evaluated for their ability to suppress disease development by AG-2-2 IIIB and AG-2-2 IV 17 days after planting. Flutolanil, polyoxin-D, and azoxystrobin provided the highest level of disease suppression. Because R. solani AG-2-2 IIIB and AG-2-2 IV are affected by temperature and moisture, growers may be able to evaluate environmental parameters for optimization of fungicide application.

scholarly journals Fusarium Root and Crown Rot: A Disease of Container-Grown Hostas

Plant Disease ◽  
2000 ◽  
Vol 84 (9) ◽  
pp. 980-988 ◽  
Author(s):  
B. Wang ◽  
S. N. Jeffers
Keyword(s):  
South Carolina ◽  
Crown Rot ◽  
Undescribed Species ◽  
Fresh Weight ◽  
Fusarium Spp ◽  
Disease Symptoms ◽  
Leaf Yellowing ◽  
Oat Seeds ◽  
Root And Crown Rot ◽  
Fusarium Sp

A previously unreported disease was observed on 11 cultivars of container-grown hosta plants at five wholesale nurseries in South Carolina between 1997 and 1999. Symptoms included leaf yellowing, plant stunting, rotting of and vascular discoloration in roots, and necrosis in the crowns. Fusarium spp. consistently were isolated from symptomatic hosta plants. Four species were recovered: F. solani, F. oxysporum, F. proliferatum, and an undescribed species designated Fusarium sp.; F. solani and Fusarium sp. were recovered most frequently. To demonstrate pathogenicity, four methods were used to inoculate hosta plants with representative isolates of F. solani, F. oxysporum, and Fusarium sp. Two types of inoculum, colonized oat seeds and conidium suspensions, were used to inoculate wounded and nonwounded plants. Disease symptoms occurred consistently only on hosta plants inoculated by dipping wounded roots and crowns into suspensions of conidia. Symptoms were most severe on plants inoculated with Fusarium sp. and much less severe on plants inoculated with F. solani or F. oxysporum. Disease severity increased and fresh weight of inoculated plants decreased when the concentration of inoculum of Fusarium sp. was increased over the range of 1 × 103 to 1 × 107 conidia per ml. Isolates of Fusarium sp., F. solani, and F. oxysporum varied in virulence when Hosta ‘Francee’ plants were inoculated. This study demonstrated that Fusarium root and crown rot of container-grown hostas is caused primarily by Fusarium sp. but that it also can be caused by F. solani and F. oxysporum. Fusarium sp. appears to be taxonomically distinct from other species, and its identity currently is under investigation.

Resin disease: a new disease of lodgepole pine dwarf mistletoe

1976 ◽  
Vol 6 (3) ◽  
pp. 415-424 ◽  
Author(s):  
Walter R. Mark ◽  
Frank G. Hawksworth ◽  
Nagayoshi Oshima
Keyword(s):  
Lodgepole Pine ◽  
Pine Bark ◽  
Disease Development ◽  
New Disease ◽  
Dwarf Mistletoe ◽  
Disease Symptoms ◽  
Parasitic Fungi ◽  
Periderm Formation

A disease syndrome (termed resin disease) of Arceuthobiumamericanum on lodgepole pine is reported in Colorado, Idaho, Montana, Utah, and Wyoming. The disease effectively kills shoots from established dwarf mistletoe plants. In one area in Colorado, all of the dwarf mistletoe plants were diseased, and most of the aerial shoots were killed. Isolations from naturally infected resin disease cankers yielded 11 fungi; Alternariaalternata and Aureobasidiumpullulans were isolated most commonly. In inoculated dwarf mistletoe plants, Alternariaalternata was the most pathogenic, and it was followed closely by Aureobasidiumpullulans. Cladosporiumherbarum and Epicoccumnigrum may also play some role in disease development. Apparently, several weakly parasitic fungi can cause resin disease symptoms. A necrophylactic periderm was found in all naturally and artificially induced resin disease cankers examined and is presumably the mechanism by which dwarf mistletoe shoots are killed. The necrophylactic periderm isolates the shoots and cortical strands from the sinkers. Periderm formation apparently results from the invasion of the pine bark by the resin disease fungi.

Efficacy of Fungicides and Biopesticides for Management of Phytophthora Crown and Root Rot of Gerber Dais

2011 ◽  
Vol 12 (1) ◽  
pp. 13 ◽  
Author(s):  
D. M. Benson ◽  
K. C. Parker
Keyword(s):  
Root Rot ◽  
Fungicide Resistance ◽  
Pathogen Resistance ◽  
Crown Rot ◽  
Disease Development ◽  
Greenhouse Production ◽  
Run Off ◽  
Action Committee ◽  
Root And Crown Rot ◽  
Crown And Root Rot

Several fungicides and biopesticides were evaluated for control of Phytophthora crown and root rot of Gerber daisy caused by P. cryptogea, a frequently encountered pathogen in greenhouse production. In greenhouse trials, biopesticides were applied 3 to 5 days before inoculation with P. cryptogea, while fungicides were applied at the time of inoculation. Efficacy of the treatments was assessed according to fresh plant top weights and root rot ratings at the end of experiments. Phosphite salt fungicides such as AgriFos, Aliette, Alude, Magellan and Vital sprayed to run off prior to inoculation were ineffective. Similarly, the strobulurins (Disarm, Heritage, and Insignia) as a drench and the biopesticides (Muscodor albus, Remedier, and Taegro) incorporated or as a drench failed to prevent root and crown rot and collapse of plants. Adorn as a drench at 2 fl oz/100 gal prevented Phytophthora crown and root rot in two of three trial years. Fenstop as a drench at 14 fl oz/100 gal or Orvego as a drench at rates of 22.5 to 34 fl oz/100 gal consistently controlled disease in three years of trials. Segway as a drench at 6 fl oz/100 gal varied in efficacy but in all trials, disease development was less than the non-treated, inoculated control. Because the effective fungicides are in different Fungicide Resistance Action Committee codes, growers have valuable rotation options for managing crown and root rot caused by P. cryptogea on Gerber daisy and avoiding pathogen resistance in the Phytophthora populations. Accepted for publication 18 February 2011. Published 12 May 2011.

scholarly journals First Report of Fusarium oxysporum f. sp. radicis-cucumerinum on Cucumber in Spain

Plant Disease ◽  
2001 ◽  
Vol 85 (11) ◽  
pp. 1206-1206 ◽  
Author(s):  
A. Moreno ◽  
A. Alférez ◽  
M. Avilés ◽  
F. Diánez ◽  
R. Blanco ◽  
...  
Keyword(s):  
Fusarium Oxysporum ◽  
Crown Rot ◽  
F1 Hybrid ◽  
Potato Dextrose Broth ◽  
Disease Symptoms ◽  
First Report ◽  
Vascular Discoloration ◽  
Root And Crown Rot ◽  
Three Stages ◽  
Stem Lesions

During December 1999, root and stem rot was observed on greenhouse-grown cucumber (cvs. Albatros, Brunex, Acapulco, and Cerrucho) plants in Almería, Spain, using rock wool cultures. The disease caused severe damage, estimated at a loss of up to 75% of the plants, in the first greenhouse affected; afterward, the disease was found in eight additional greenhouses (14 ha) in 1999 and 2000. Stem lesions extended up to 10 to 12 cm above the crown in mature plants, although no fruit damage was observed. In the advanced stages, abundant development of orange sporodochia was evident on crown and stem lesions, without vascular discoloration. Root, crown, and stem pieces that were placed on potato dextrose agar (PDA) after surface-disinfection with 5% sodium hypochlorite, rinsed, and dried resulted in pure fungal colonies. Based on morphological characteristics of conidia, phialides, and chlamydospores from the isolations, the fungus was identified as Fusarium oxysporum Schlechtend.:Fr. Pathogenicity tests were conducted on cucumber (cvs. Marketmore 76 and Cerrucho [F1 hybrid]), melon (cvs. Amarillo oro, Perlita, Piboule, Tania, and Nipper [F1]), watermelon (cvs. Sugar Baby, Sweet Marvel, Jubilee, and Pata Negra and hybrid Crimson sweet), Cucurbita maxima × Cucurbita moschata, zucchini (cv. Senator), and loofah (Luffa aegyptiaca) at several stages: (i) pregermination; (ii) 1 or 2 true leaves; and (iii) more than 10 true leaves. Five fungal isolates were grown on PDA or shaken potato dextrose broth at 25°C for 8 days. Inoculation was performed in pots (10 seeds or plants of each cultivar or hybrid and isolate) by drenching with 100 ml of a fungal suspension (104 to 106 CFU/ml). Sterile water was applied to noninoculated control plants. Tests were repeated in growth chambers at 25°C (night) and 28°C (day) with a 16-h photoperiod. Fifteen to fifty days after inoculation, cucumber and melon plants at all three stages developed symptoms of root and crown rot in 100% of inoculated plants, with no observed vascular discoloration. Fifty days after inoculation, all three stages of C. maxima × C. moschata and zucchini remained symptomless. Loofah and watermelon germinated poorly or not at all when inoculated at the pregermination stage. Fifteen to fifty days after inoculation, 100% of inoculated cucumber and melon plants developed symptoms. Watermelon plants inoculated at the 10 or more true-leaf stage did not develop disease symptoms. No symptoms developed on noninoculated control plants. F. oxysporum was reisolated from infected roots, crowns, and stems of inoculated plants, confirming Koch's postulates. The main symptoms on cucumber infected by F. oxysporum f. sp. cucumerinum are wilt, yellowing, and vascular discoloration. In contrast, based on inoculation of the host differentials and the resulting disease symptoms found in this study, the fungus was identified as F. oxysporum f. sp. radicis-cucumerinum (1). To our knowledge, this is the first report of F. oxysporum f. sp. radicis-cucumerinum causing root and crown rot in cucumber in Spain. Reference: (1) D. J. Vakalounakis. Plant Dis. 80:313, 1996.

scholarly journals Suppression of Phytophthora Root and Crown Rot on Pepper Plants Treated with Acibenzolar-S-Methyl

Plant Disease ◽  
2002 ◽  
Vol 86 (3) ◽  
pp. 292-297 ◽  
Author(s):  
M. E. Matheron ◽  
M. Porchas
Keyword(s):  
Phytophthora Capsici ◽  
Stem Canker ◽  
Crown Rot ◽  
Management Tool ◽  
Disease Development ◽  
Phytophthora Blight ◽  
Chile Pepper ◽  
Bell Tower ◽  
Root And Crown Rot ◽  
Pepper Plants

The fungicide mefenoxam is registered for the control of Phytophthora blight of peppers caused by Phytophthora capsici. Isolates of the pathogen that are insensitive to mefenoxam, however, have been detected in some locations. Consequently, alternative methods are needed to control Phytophthora blight of peppers. Acibenzolar-S-methyl (ABM, Actigard) is a chemical activator of plant disease resistance that has potential for the management of Phytophthora blight of peppers. The effect of foliar applications of ABM on the development of root and crown rot on pepper plants grown in the greenhouse and inoculated with Phytophthora capsici or in soil naturally infested with the pathogen was evaluated. Inhibition of stem canker development on pepper cvs. Bell Tower and AZ9 after four treatments with ABM (75 μg/ml) was significantly greater than on plants receiving a single application of the chemical. Stem canker length on Bell Tower or AZ9 peppers was inhibited by 93.2 to 97.2% and 87.4 to 92.4% when plants were inoculated with P. capsici at 1 or 5 weeks, respectively, after the fourth application of ABM. Survival of chile pepper plants grown in field soil naturally infested with P. capsici was significantly increased by three foliar applications of ABM (75 μg/ml) compared with nontreated plants in all three trials when pots were watered daily and in two of three trials when pots were flooded for 48 h every 2 weeks. When soil was flooded every 2 weeks to establish conditions highly favorable for disease development, plants treated once with mefenoxam (100 μg/ml) survived significantly longer than those treated with ABM. On the other hand, when water was provided daily without periodic flooding to establish conditions less favorable for disease development, plant survival between the two chemicals was not different in two of three trials. Length of survival among chile pepper plants treated twice with 25, 50, or 75 μg/ml of ABM and grown in soil infested with P. capsici was not different. This work indicates that ABM could be an important management tool for Phytophthora root and crown rot on pepper plants.

Static and Dynamic Studies of Gasoline in View of its Octane Number and its Toxic Effect

2013 ◽  
Vol 12 (7) ◽  
pp. 451-459
Author(s):  
Ashraf Yehia El-Naggar ◽  
Mohamed A. Ebiad
Keyword(s):  
Toxic Effect ◽  
Aromatic Hydrocarbons ◽  
Octane Number ◽  
Liquid Fuel ◽  
Positive Impact ◽  
Hydrocarbon Composition ◽  
Different Temperatures ◽  
Different Seasons ◽  
The One ◽  
The Impact

Gasoline come primarily from petroleum cuts, it is the preferred liquid fuel in our lives. Two gasoline samples of octane numbers 91 and 95 from Saudi Arabia petrol stations were studied. This study was achieved at three different temperatures 20oC, 30oC and 50oC representing the change in temperatures of the different seasons of the year. Both the evaporated gases of light aromatic hydrocarbons (BTEX) of gasoline samples inside the tank were subjected to analyze qualitatively and quantitatively via capillary gas chromatography. The detailed hydrocarbon composition and the octane number of the studied gasoline samples were determined using detailed hydrocarbon analyzer. The idea of research is indicating the impact of light aromatic compounds in gasoline on the toxic effect of human and environment on the one hand, and on octane number of gasoline on the other hand. Although the value of octane number will be reduced but this will have a positive impact on the environment as a way to produce clean fuel.

scholarly journals Clonal approaches to understanding the impact of mutations on hematologic disease development

Blood ◽  
2019 ◽  
Vol 133 (13) ◽  
pp. 1436-1445 ◽  
Author(s):  
Jyoti Nangalia ◽  
Emily Mitchell ◽  
Anthony R. Green
Keyword(s):  
Somatic Mutations ◽  
Clonal Selection ◽  
Single Cells ◽  
Driver Mutations ◽  
Great Promise ◽  
Tumor Evolution ◽  
Disease Development ◽  
Hematopoietic Tissue ◽  
The Impact

Abstract Interrogation of hematopoietic tissue at the clonal level has a rich history spanning over 50 years, and has provided critical insights into both normal and malignant hematopoiesis. Characterization of chromosomes identified some of the first genetic links to cancer with the discovery of chromosomal translocations in association with many hematological neoplasms. The unique accessibility of hematopoietic tissue and the ability to clonally expand hematopoietic progenitors in vitro has provided fundamental insights into the cellular hierarchy of normal hematopoiesis, as well as the functional impact of driver mutations in disease. Transplantation assays in murine models have enabled cellular assessment of the functional consequences of somatic mutations in vivo. Most recently, next-generation sequencing–based assays have shown great promise in allowing multi-“omic” characterization of single cells. Here, we review how clonal approaches have advanced our understanding of disease development, focusing on the acquisition of somatic mutations, clonal selection, driver mutation cooperation, and tumor evolution.

scholarly journals Effect of temperature, CO2 and O2 on motility and mobility of Anisakidae larvae

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aiyan Guan ◽  
Inge Van Damme ◽  
Frank Devlieghere ◽  
Sarah Gabriël
Keyword(s):  
Enzymatic Digestion ◽  
Infected Fish ◽  
Effect Of Temperature ◽  
Video Recordings ◽  
Different Temperatures ◽  
Semi Solid ◽  
Zoonotic Parasites ◽  
The Impact ◽  
Phosphate Buffered Saline

AbstractAnisakidae, marine nematodes, are underrecognized fish-borne zoonotic parasites. Studies on factors that could trigger parasites to actively migrate out of the fish are very limited. The objective of this study was to assess the impact of different environmental conditions (temperature, CO2 and O2) on larval motility (in situ movement) and mobility (migration) in vitro. Larvae were collected by candling or enzymatic digestion from infected fish, identified morphologically and confirmed molecularly. Individual larvae were transferred to a semi-solid Phosphate Buffered Saline agar, and subjected to different temperatures (6 ℃, 12 ℃, 22 ℃, 37 ℃) at air conditions. Moreover, different combinations of CO2 and O2 with N2 as filler were tested, at both 6 °C and 12 °C. Video recordings of larvae were translated into scores for larval motility and mobility. Results showed that temperature had significant influence on larval movements, with the highest motility and mobility observed at 22 ℃ for Anisakis spp. larvae and 37 ℃ for Pseudoterranova spp. larvae. During the first 10 min, the median migration of Anisakis spp. larvae was 10 cm at 22 ℃, and the median migration of Pseudoterranova spp. larvae was 3 cm at 37 ℃. Larval mobility was not significantly different under the different CO2 or O2 conditions at 6 °C and 12 ℃. It was concluded that temperature significantly facilitated larval movement with the optimum temperature being different for Anisakis spp. and Pseudoterranova spp., while CO2 and O2 did not on the short term. This should be further validated in parasite-infected/spiked fish fillets.

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