scholarly journals Effect of fungicide application on Wheat Head Blight, occurrence of Fusarium spp. and mycotoxin production

2011 ◽  
Vol 63 (1) ◽  
pp. 29-38 ◽  
Author(s):  
A. Baturo-Cieśniewska ◽  
A. Lukanowski ◽  
M. Kolenda
Keyword(s):  
Dose Rate ◽  
The Other ◽  
Type B ◽  
Head Blight ◽  
Fusarium Spp ◽  
Mycotoxin Production ◽  
Fungicide Application ◽  
High Incidence ◽  
Different Doses ◽  
Advantageous Effect

Effect of fungicide application on Wheat Head Blight, occurrence of Fusarium spp. and mycotoxin production The aim of the study was to determine if azoxystrobin and metconazole used for the control of wheat FHB at half, full, and quarter more the recommended dose rate may affect in differentiated way on the occurrence of Fusarium spp. and their ability to mycotoxin production in harvested grain, in wheat ears artificially inoculated with two DON-producing isolates of F. culmorum. Macroscopic evaluation showed high incidence of fusariosis. Plant health in the plots where the heads were artificially inoculated and fungicide was not applied was similar to the protected ones. Only increasing the dose metconazole resulted in a stronger reduction of fusariosis. The advantageous effect of azoxystrobin was not observed. Mycological analysis of harvested grain showed the presence of a number of F. culmorum, but from samples sprayed with metconazole it was isolated in smaller quantities. Also F. avenaceum, F. graminearum, F. poae and F. tricinctum were isolated. Molecular analysis showed the presence of F. culmorum in all samples of harvested grain. Also genes from Tri cluster were identified, involved in the synthesis of type-A and type-B trichothecenes - especially DON and 3Ac-DON. Chromatography revealed the presence of small quantities of mycotoxins. In all samples DON and 3Ac-DON were predominant. In general, F. culmorum isolate, which caused weaker symptoms of FHB and was less numerously isolated from grain that the other one, produced smaller amounts of mycotoxins. Samples protected with azoxystrobin contain the largest quantities of DON. Effect of different doses of fungicides on the number of mycotoxins was not clearly established.

Relative Distribution and Incidence of Viruses Associated with Disease Outbreaks in Tomato Fields in Trinidad

2006 ◽  
Vol 7 (1) ◽  
pp. 29
Author(s):  
S. N. Rampersad
Keyword(s):  
Production Systems ◽  
Management Strategies ◽  
Disease Outbreaks ◽  
Tobacco Etch Virus ◽  
The Other ◽  
Multiple Infections ◽  
Relative Distribution ◽  
Tomato Production ◽  
Viral Pathogen ◽  
High Incidence

Tomato production in Trinidad has suffered considerable losses in yield and fruit quality due to infections of hitherto surmised etiology. In order to develop strategies for controlling viral diseases in tomato, the relative distribution and incidence of seven viruses that commonly infect tomato were determined. Of the 362 samples tested, Potato yellow mosaic Trinidad virus (PYMTV) was found in every farm except two and was present at relatively high incidence throughout the country. Tobacco mosaic virus (TMV) and Tobacco etch virus (TEV) were found in fewer farms and at lower incidences while the other viruses were absent. Single infections of either virus were more common than double infections and multiple infections were rare but present. The results indicated that PYMTV is the predominant and most important viral pathogen in tomato production systems in Trinidad; however, begomovirus disease management strategies will also have to accommodate controls Accepted for publication 10 January 2006. Published 9 March 2006.

Anatomie, histologie et affinités de l'appareil séricigène des Hersilia Sav. et Aud. (Araneae: Hersiliidae)

1984 ◽  
Vol 62 (1) ◽  
pp. 97-106 ◽  
Author(s):  
Jacqueline Kovoor
Keyword(s):  
Type A ◽  
The Other ◽  
Secretory Cells ◽  
Evolutionary Stage ◽  
Type B ◽  
Outer Coat ◽  
Silk Glands ◽  
Single Protein

Although hersiliid spiders do not spin any webs, their silk glands, which belong to six types, are large and complex. Two groups of ampullate glands, one opening on the anterior spinnerets and the other on the median spinnerets, secrete two proteins each. About 180 pyriform glands are clearly bipartite. Over 200 type A aciniform glands opening on the median and posterior spinnerets are made up of three categories of secretory cells. Silk from these glands consists of two proteins (core and outer coat) joined together by an intermediary layer of acidic glycoprotein. All the 160 type B aciniform glands opening on the posterior spinnerets secrete a single protein. Fifty tubuliform glands opening on the median and posterior spinnerets produce two proteins, one of which is coloured. As in Urocteinae, long posterior spinnerets and large, numerous aciniform and tubuliform glands are correlated with swathing of prey and egg-cocoon construction. In Lycosidae and Agelenidae, the ampullate glands show the same number and distribution according to the spinnerets. However, anatomical and histochemical features of hersiliid aciniform and ampullate glands are close to those of some Araneoidea. Apart from peculiar characteristics, silk glands of Hersilia might represent an intermediate evolutionary stage towards Araneoidea.

scholarly journals Survival and Inoculum Production of Gibberella zeae in Wheat Residue

Plant Disease ◽  
2004 ◽  
Vol 88 (7) ◽  
pp. 724-730 ◽  
Author(s):  
S. A. Pereyra ◽  
R. Dill-Macky ◽  
A. L. Sims
Keyword(s):  
Management Strategies ◽  
Soil Surface ◽  
Triticum Aestivum L ◽  
Gibberella Zeae ◽  
Effective Management ◽  
Head Blight ◽  
Fusarium Spp ◽  
Residue Decomposition ◽  
Inoculum Production ◽  
Mesh Bags

Survival and inoculum production of Gibberella zeae (Schwein.) Petch (anamorph Fusarium graminearum (Schwabe)), the causal agent of Fusarium head blight of wheat and barley, was related to the rate of wheat (Triticum aestivum L.) residue decomposition. Infested wheat residue, comprising intact nodes, internodes, and leaf sheaths, was placed in fiberglass mesh bags on the soil surface and at 7.5- to 10-cm and 15- to 20-cm depths in chisel-plowed plots and 15 to 20 cm deep in moldboard-plowed plots in October 1997. Residue was sampled monthly from April through November during 1998 and every 2 months through April to October 1999. Buried residue decomposed faster than residue placed on the soil surface. Less than 2% of the dry-matter residue remained in buried treatments after 24 months in the field, while 25% of the residue remained in the soil-surface treatment. Survival of G. zeae on node tissues was inversely related to the residue decomposition rate. Surface residue provided a substrate for G. zeae for a longer period of time than buried residue. Twenty-four months after the initiation of the trial, the level of colonization of nodes in buried residue was half the level of colonization of residue on the soil surface. Colonization of node tissues by G. zeae decreased over time, but increased for other Fusarium spp. Ascospores of G. zeae were still produced on residue pieces after 23 months, and these spores were capable of inducing disease. Data from this research may assist in developing effective management strategies for residues infested with G. zeae.

Distribution dynamics of Fusarium spp. causing Fusarium head blight (FHB) in wheat at different geographical locations in India

2017 ◽  
Vol 6 (5) ◽  
pp. 167-177
Author(s):  
Vipin Panwar ◽  
Ashok Aggarwal ◽  
Surinder Paul ◽  
Jitender Kumar ◽  
M. S. Saharan
Keyword(s):  
Fusarium Head Blight ◽  
Geographical Area ◽  
Climatic Conditions ◽  
Individual Species ◽  
Relative Distribution ◽  
Head Blight ◽  
Distribution Dynamics ◽  
Fusarium Spp ◽  
Geographical Regions ◽  
Geographical Locations

Fusarium head blight (FHB) or head Scab is a very devastating fungal disease of wheat. Epidemics results with severe yield losses and overall seed quality reduction due to mycotoxins contaminated grains. Several species of Fusarium are found associated with the disease. But, incidence and severity of FHB and the composition of Fusarium species involved are reported to vary among geographical regions and years due to variations in climatic condi-tions and cropping practices. Climatic conditions, and even local variations in weather, can limit the range of species observed even if several are present, and influence their relative frequency of recovery. Our present study gives an idea about the distribution dynamics of FHB causing Fusarium spp. at three different locations in India. Most of the species can be found in much of geographical area affected but individual species dominate a specific re-gion. Analysis of the results of present study indicated that three Fusarium spp. i.e. F. graminearum, F. pallidoroseum and F. oxysporum were found as-sociated with FHB but F. graminearum was the dominant in all the location surveyed. Other two species are also associated with the disease but fre-quency was low. As these geographical locations represent different climatic conditions, the high relative distribution frequency of F. graminearum indi-cates its better adaptability to variable environmental conditions. Under-standing the pathogen distribution dynamics may also provide insights into the epidemiology and evolutionary potential of Fusarium spp. and could lead to improved management strategies under present climate change scenario.

How “Native” Are Heritage Speakers?

2013 ◽  
Vol 10 (2) ◽  
pp. 153-177 ◽  
Author(s):  
Silvina Montrul
Keyword(s):  
Language Learning ◽  
Experimental Evidence ◽  
Native Speakers ◽  
Learning Experience ◽  
Age Of Acquisition ◽  
The Other ◽  
Gender Agreement ◽  
Heritage Speakers ◽  
High Incidence ◽  
Incomplete Acquisition

One of the chief characteristics of heritage speakers is that they range in proficiency from “overhearers” to “native” speakers. To date, the vast majority of linguistic and psycholinguistic studies have characterized the non-target-like linguistic abilities of heritage speakers as a product of incomplete acquisition and/or attrition due to reduced exposure and opportunities to use the language during childhood. This article focuses on the other side of the problem, emphasizing instead the high incidence of native-like abilities in adult heritage speakers. I illustrate this issue with recent experimental evidence from gender agreement in Spanish, a grammatical feature that is mastered at almost 100% accuracy in production by native speakers;yet it is one of the most difficult areas to master for non-native speakers, including near-natives.I discuss how age of acquisition and language-learning experience explain these effects.

Pharmacogenetics: Its Place in Medicine and Biology

1992 ◽  
Vol 5 (6) ◽  
pp. 312-316 ◽  
Author(s):  
Werner Kalow
Keyword(s):  
Infectious Disease ◽  
Drug Toxicity ◽  
Rare Variants ◽  
The Other ◽  
New Drugs ◽  
Case Histories ◽  
High Incidence ◽  
New Knowledge ◽  
Toxic Exposures ◽  
Technical Advances

A young science serves its purpose if it leads not only to new knowledge, but to new insights and concepts. This article opens with examples to illustrate some former thinking that the introduction of pharmacogenetic has overcome. Pharmacogenetic case histories from discovery to the present illustrate the interlocking of observations, technical advances, and changing concepts. There are striking biological similarities between pharmacogenetics and those inborn factors that cause resistance to infectious disease: Both represent person-to-person variations that may help the survival of populations, one when facing massive toxic exposures, the other when facing plagues and epidemics. Thus pharmacogenetics represents a biologically necessary variability of the defenses against chemical intruders, and this includes drugs. While this variability is desirable, drug toxicity occurring on the basis of this variability must be avoided. The most successful defendants against toxicity due to polymorphic (ie, high incidence) variants should be the designers of new drugs. The only defender concerned with rare variants can be the attentive clinician.

scholarly journals Effects of Integrating Cultivar Resistance and Fungicide Application on Fusarium Head Blight and Deoxynivalenol in Winter Wheat

Plant Disease ◽  
2011 ◽  
Vol 95 (5) ◽  
pp. 554-560 ◽  
Author(s):  
Stephen N. Wegulo ◽  
William W. Bockus ◽  
John Hernandez Nopsa ◽  
Erick D. De Wolf ◽  
Kent M. Eskridge ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Fusarium Head Blight ◽  
Field Experiments ◽  
Economic Losses ◽  
Cultivar Resistance ◽  
Head Blight ◽  
Resistant Cultivars ◽  
Fungicide Application ◽  
Fungicide Efficacy ◽  
Moderately Resistant

Fusarium head blight (FHB) or scab, incited by Fusarium graminearum, can cause significant economic losses in small grain production. Five field experiments were conducted from 2007 to 2009 to determine the effects on FHB and the associated mycotoxin deoxynivalenol (DON) of integrating winter wheat cultivar resistance and fungicide application. Other variables measured were yield and the percentage of Fusarium-damaged kernels (FDK). The fungicides prothioconazole + tebuconazole (formulated as Prosaro 421 SC) were applied at the rate of 0.475 liters/ha, or not applied, to three cultivars (experiments 1 to 3) or six cultivars (experiments 4 and 5) differing in their levels of resistance to FHB and DON accumulation. The effect of cultivar on FHB index was highly significant (P < 0.0001) in all five experiments. Under the highest FHB intensity and no fungicide application, the moderately resistant cultivars Harry, Heyne, Roane, and Truman had less severe FHB than the susceptible cultivars 2137, Jagalene, Overley, and Tomahawk (indices of 30 to 46% and 78 to 99%, respectively). Percent fungicide efficacy in reducing index and DON was greater in moderately resistant than in susceptible cultivars. Yield was negatively correlated with index, with FDK, and with DON, whereas index was positively correlated with FDK and with DON, and FDK and DON were positively correlated. Correlation between index and DON, index and FDK, and FDK and DON was stronger in susceptible than in moderately resistant cultivars, whereas the negative correlation between yield and FDK and yield and DON was stronger in moderately resistant than in susceptible cultivars. Overall, the strongest correlation was between index and DON (0.74 ≤ R ≤ 0.88, P ≤ 0.05). The results from this study indicate that fungicide efficacy in reducing FHB and DON was greater in moderately resistant cultivars than in susceptible ones. This shows that integrating cultivar resistance with fungicide application can be an effective strategy for management of FHB and DON in winter wheat.

scholarly journals Incidence of leaf rot disease in relation to root (wilt) in young coconut palms and fungi in lamina and petiole lesions

CORD ◽  
2004 ◽  
Vol 20 (02) ◽  
pp. 34
Author(s):  
N. Srinivasan
Keyword(s):  
Tamil Nadu ◽  
Integrated Management ◽  
Systemic Infection ◽  
The Other ◽  
Wet Season ◽  
Fusarium Spp ◽  
Leaf Petiole ◽  
Exserohilum Rostratum ◽  
Rot Disease ◽  
Leaf Rot

Coconut leaf rot in association with root (wilt) is widespread in southern districts of Kerala, India. The disease complex has spread to northern districts of the state and also adjacent districts in Tamil Nadu. Where as the root (wilt) is a systemic infection (due to phytoplasma) the leaf rot is a foliar syndrome due to fungi (Colletotrichum gloeosporioides, Exserohilum rostratum, Fusarium spp.). Occurrence of leaf rot has been related to the incidence of root (wilt) and its appearance in young palms remained a matter of contention as to which disease precedes the other. Leaf rot lesions do occur on leaf petiole/mid-vein/mid-rib even as the disease lesions are known to be common on lamina (spindles). Investigations brought out that in majority of leaf rot affected young palms (2-5 years old) the flaccidity symptom of root (wilt) could be also discerned. In lesser number of affected palms, the other symptoms of root (wilt), yellowing and marginal necrosis, were also visible. As such, in 88.5% of leaf rot affected young palms one or the other symptom of root (wilt) has been recorded irrespective of season. C. gloeosporioides, E. rostratum and other fungi were found both in lamina and petiole lesions in different months. C. gloeosporioides was detected from petiole and lamina tissues in all the months, followed by E. rostratum, Fusarium spp. etc. C. gloeosporioides was isolated from these parts in more numbers and consistently during January-December. E. rostratum appeared erratically. Aggressiveness of C. gloeosporioides during months of wet season was confirmed. Fusarium spp. was isolated predominantly from these parts in dry months (January-May). Knowledge on occurrence of leaf rot in young palms in relation to root (wilt) and dynamics of leaf rot pathogens in leaf parts among months/seasons of year (in inoculums build-up, spread and dissemination) are important in the context of integrated management of root (wilt)-leaf rot complex.

scholarly journals Reaction to Fusarium Head Blight (FHB) of Six New Wheat Cultivars Widely Grown in Transylvania

1970 ◽  
Vol 66 (1) ◽  
Author(s):  
Sardar AMIN ◽  
Marin ARDELEAN ◽  
Vasile MOLDOVAN ◽  
Rodica CADAR
Keyword(s):  
Grain Yield ◽  
Fusarium Head Blight ◽  
Wheat Cultivars ◽  
Head Blight ◽  
Fusarium Spp ◽  
Developmental Progress ◽  
Progress Curve ◽  
Symptom Intensity ◽  
Winter Wheat Cultivars ◽  
Artificial Inoculations

Fusarium head blight (FHB), caused by Fusarium spp., has become one of the most destructive diseases in the world’s wheat growing areas , especially in the humid and semihumid regions (Paillard et al. 2004, Mesterhazy 1978, Stack & Mullen 1985; Kiecana 1987; Kiecana et al. 1988). Six winter wheat cultivars, recently released and widely grown in Trasylvania, have been evaluated for FHB resistance during 2006. The evaluation was made by means of artificial inoculations with Fusarium graminearum and assesment of symptom intensity by computing AUDPC index (Area Under Developmental Progress Curve). Based on these data, two cultivars (Dumbrava and Turda 195) were considered as resistant, two cultivars (Ardeal and Arieşan) as medium resistant and other two cultivars (Fundulea 4 and GK Öthalom) as susceptible to FHB. The reaction to FHB of the six tested cultivars, based on the postharvest indices, showed significant differences among these cultivars as far as the yield elements and the total grain yield were considered. Actually, in the resistant cultivars, both the total grain yield and some of the yield elements (spike wight, grain weght/spike and 1000 kernel weigt) were significantly less affected by FHB than in medium resistant and susceptible cultivars.

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