Evaluation of spray nozzles for fungicidal control of tan spot in wheat

2017 ◽  
Vol 68 (7) ◽  
pp. 591
Author(s):  
Juan J. Olivet ◽  
Juana Villalba ◽  
Jorge Volpi
Keyword(s):  
Grain Yield ◽  
Spray Deposition ◽  
Tan Spot ◽  
First Year ◽  
Systemic Fungicide ◽  
Pyrenophora Tritici Repentis ◽  
Progress Curve ◽  
Tan Spot Disease ◽  
Extended Range ◽  
And Control

Tan spot, caused by Pyrenophora tritici-repentis (Died.) Drechs, is a serious constraint on wheat yields in the Southern Cone region of South America. A 2-year experiment was conducted to evaluate fungicide deposition, disease development and grain yield. Three spray nozzles were evaluated: an air-induction flat fan (AI), a wide-angle flat fan (TT), and an extended-range flat fan (XR). A systemic fungicide containing azoxystrobin and cyproconazole was used in both years. Tan spot severity and the area under non-green leaf area disease progress curve (AUNGLA) were analysed. There were no significant differences in deposition among nozzles, and no significant interactions between nozzles and leaf layers in the first year. In both years, AUNGLAs were similar for the three nozzles types, and the tan spot severity in untreated plots was significantly higher than in fungicide-applied plots. Grain yield was higher in the fungicide-applied plots, and there were no significant differences among nozzles in both years. Droplet size had no effect on the fungicide’s efficacy for tan spot control in Uruguay across three susceptible wheat cultivars. The use of drift-reducing nozzles and a systemic fungicide in these trials led to satisfactory performance for spray deposition, canopy penetration and control of the tan spot disease of wheat in the same way as expected from conventional nozzles.

scholarly journals Comparison of Greenhouse and Field Testing to Identify Wheat Resistant to Tan Spot

Plant Disease ◽  
1999 ◽  
Vol 83 (3) ◽  
pp. 269-273 ◽  
Author(s):  
C. K. Evans ◽  
R. M. Hunger ◽  
W. C. Siegerist
Keyword(s):  
Grain Yield ◽  
Field Testing ◽  
Kernel Weight ◽  
Tan Spot ◽  
Lesion Length ◽  
Pyrenophora Tritici Repentis ◽  
Progress Curve ◽  
Large Numbers ◽  
Field Reaction ◽  
Wheat Lines

Incorporation of tan spot resistance into adapted wheat (Triticum aestivum) lines requires screening procedures in the greenhouse and field that correctly identify reaction to tan spot. This study compares greenhouse (seedling) and field (adult plants) testing of wheat lines for reaction to tan spot following inoculation with conidia by Pyrenophora tritici-repentis. Mistirrigation was used to provide adequate moisture for infection by P. tritici-repentis in the greenhouse and in the field. Reaction of seedlings to tan spot in the greenhouse was measured by lesion length. Area under the disease progress curve (AUDPC) was used to determine reaction in the field. The effect of tan spot on grain yield and kernel weight was determined by comparing inoculated with fungicide-sprayed split-plot values. In greenhouse tests, lesion length ranged from 1.2 to 4.1 mm. Lesions were 1.2 mm long on Red Chief, a tan spot-resistant check. Lesions were 3.6 mm long on TAM 105, a tan spot-susceptible check. Four breeder lines had levels of seedling (greenhouse) resistance nearly equal to that of Red Chief. Ranks of lesion length and field assessments of the AUDPC were significantly correlated (r = 0.75 to 0.93, P ≤0.05). Thus, greenhouse assessment was useful for screening large numbers of wheat genotypes for reaction to tan spot and identifying selected entries for further screening in the field. Mean grain yield from P. tritici-repentis inoculated plots was approximately 15% less than yield from fungicide-sprayed plots. Kernel weight was reduced an average of 7 and 13% at two field locations.

scholarly journals Characterizing Virulence of the Pyrenophora tritici-repentis Isolates Lacking Both ToxA and ToxB Genes

Pathogens ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 74 ◽  
Author(s):  
Jingwei Guo ◽  
Gongjun Shi ◽  
Zhaohui Liu
Keyword(s):  
Triticum Aestivum L ◽  
Tan Spot ◽  
Pyrenophora Tritici Repentis ◽  
Tan Spot Disease ◽  
Hard Red Winter Wheat ◽  
Winter Wheat Cultivars ◽  
Race 2 ◽  
Genomic Regions ◽  
Race 4 ◽  
Necrotrophic Effectors

The fungus Pyrenophora tritici-repentis (Ptr) causes tan spot of wheat crops, which is an important disease worldwide. Based on the production of the three known necrotrophic effectors (NEs), the fungal isolates are classified into eight races with race 4 producing no known NEs. From a laboratory cross between 86–124 (race 2 carrying the ToxA gene for the production of Ptr ToxA) and DW5 (race 5 carrying the ToxB gene for the production of Ptr ToxB), we have obtained some Ptr isolates lacking both the ToxA and ToxB genes, which, by definition, should be classified as race 4. In this work, we characterized virulence of two of these isolates called B16 and B17 by inoculating them onto various common wheat (Triticum aestivum L.) and durum (T. turgidum L.) genotypes. It was found that the two isolates still caused disease on some genotypes of both common and durum wheat. Disease evaluations were also conducted in recombinant inbred line populations derived from two hard red winter wheat cultivars: Harry and Wesley. QTL mapping in this population revealed that three genomic regions were significantly associated with disease, which are different from the three known NE sensitivity loci. This result further indicates the existence of other NE-host sensitivity gene interactions in the wheat tan spot disease system.

scholarly journals Evaluation of Pyrenophora tritici-repentis Infection of Wheat Heads

Agriculture ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 417
Author(s):  
Pao Theen See ◽  
Nikki Schultz ◽  
Caroline S. Moffat
Keyword(s):  
Recovery Rate ◽  
Pcr Detection ◽  
Tan Spot ◽  
Spore Suspension ◽  
Etiological Agent ◽  
Seed Infection ◽  
Grain Development ◽  
Spot Disease ◽  
Pyrenophora Tritici Repentis ◽  
Tan Spot Disease

The incidence of wheat head infection by Pyrenophora tritici-repentis (Ptr), the etiological agent of tan spot disease, was evaluated during grain development in a glasshouse experiment. Heads artificially inoculated with a Ptr spore suspension developed widespread brown spots across the spikelets, and mycelia and conidophores were observed on glumes and awns. Seeds of heavily infected heads were darkened and shrivelled, but no red smudge symptoms were apparent. The recovery rate of Ptr isolates from the inoculated wheat heads was low, and colonies that were re-isolated displayed an irregular morphology with reddish mycelia when grown on agar plates. The presence of Ptr on inoculated wheat heads was assessed directly via PCR detection, and a limitation of Ptr hyphae to proliferate beyond the point of contact of spore inoculum on floret tissues was observed. The systemic transmission of Ptr from infected seeds was minimal; however, saprophytic growth of the pathogen occurred on the senescing leaves of wheat plants grown from inoculated seeds. Thus, even though Ptr seed infection is not as common as foliar infection, infected seeds are still a source of disease inoculum and screening for pathogen contamination is advisable.

scholarly journals Comparison of the efficacy of QoI fungicides, alone or in mixture with triazoles, in Asian soybean rust control, 2016/17 growing season

2019 ◽  
Vol 45 (1) ◽  
pp. 28-32 ◽  
Author(s):  
Erlei Melo Reis ◽  
Luis Henrique Carregal ◽  
Mateus Zanatta
Keyword(s):  
Grain Yield ◽  
Soybean Rust ◽  
Phenological Stages ◽  
Control Efficacy ◽  
Qoi Fungicides ◽  
Asian Soybean Rust ◽  
Progress Curve ◽  
Crop Cycle ◽  
And Control ◽  
Positive Effect

ABSTRACT Evolution has been reported for the reduction in Phakopsora pachyrhizi sensitivity to the mixtures of the three site-specific mechanisms of action (DMIs, QoIs and SDHIs) used in its control. The aim of this study was to quantify the current contribution of QoIs, alone or in mixture with triazoles, in the control of Asian soybean rust. In an experiment carried out in the field, the efficacy of quinone outside inhibitors (QoIs), or strobilurins, was compared for Asian soybean rust control. The isolated effects of four doses of azoxystrobin, picoxystrobin, pyraclostrobin and trifloxystrobin were evaluated, as well as of four applications during the crop cycle. Control by commercial mixtures of these QoIs with triazoles was also compared. Severity was evaluated in four phenological stages, and control was calculated based on final severity data, area under rust progress curve, defoliation, one-thousand-grain mass, grain yield and damage caused by the disease. The lowest mean of rust control efficacy resulted from applications of azoxystrobin (15.8 and 11.19%) and pyraclostrobin (15.4 and 16.76%) and the highest mean was found for picoxystrobin (54.1 and 54.35 %) and trifloxystrobin (69.7 and 64.46%), calculated based on final severity and AUDPC, respectively. Such efficacy is not enough to cover the fungicide application cost, although there was a positive effect of treatments on disease control and grain yield.

scholarly journals Controlling Foliar Blight of Wheat through Nutrient Management and Varietal Selection

2014 ◽  
Vol 9 ◽  
pp. 85-93
Author(s):  
Yuba R. Kandel ◽  
Jaya P. Mahato
Keyword(s):  
Grain Yield ◽  
Nutrient Management ◽  
Bipolaris Sorokiniana ◽  
Tan Spot ◽  
Research Station ◽  
Wheat Genotypes ◽  
Nitrogen Levels ◽  
Growing Seasons ◽  
Foliar Blight ◽  
Progress Curve

Helminthosporium leaf blight, a complex of spot blotch caused by Bipolaris  sorokiniana and tan spot caused by Pyrenophora tritici-repentis, is one of   the most important foliar diseases of wheat in Nepal. It appears in almost all wheat growing areas and causes severe yield loss every year. A study was   conducted at Regional Agriculture Research Station (RARS), Tarahara, Sunsari during 2004-05 and 2005-06 wheat growing seasons to elucidate role of nitrogen in wheat genotypes for management of the disease. Field experiment was laid out on split plot design with three replications. Four doses of nitrogen in six different promising genotypes were tested. Nitrogen   levels higher than 50 kg ha-1 significantly reduced disease severity and increased grain yield in all genotypes but there was no significant differences in grain yield in the first year. In the second year, grain yield difference   among the genotypes was significant. Area under disease progress curve(AUDPC) was not significant between two doses 100 and 150 kg ha-1. The wheat genotypes showed different reactions to disease. Genotype BL 2047   had the lowest incidence of disease followed by BL 1887, whereas BL 2217 had the highest incidence of the disease. Genotype BL 2196 produced the highest grain yield (2172 kg ha-1) and the lowest grain yield was obtained in Bhrikuti followed by BL 2089. These results suggested that fertilizer should be applied in soil at balanced dose 100:50:50 N:P2O5:K2O kg ha-1. Growing relatively resistant genotypes with the balance dose of fertilizers can reduce foliar blight severity in wheat.Nepal Agric. Res. J. Vol. 9, 2009, pp. 85-93DOI: http://dx.doi.org/10.3126/narj.v9i0.11645

Tan spot disease under the lenses of plant pathologists

2021 ◽  
pp. 589-622
Author(s):  
Reem Aboukhaddour ◽  
◽  
Mohamed Hafez ◽  
Stephen E. Strelkov ◽  
Myriam R. Fernandez ◽  
...  
Keyword(s):  
Plant Pathology ◽  
Crop Production ◽  
Plant Pathogens ◽  
Tan Spot ◽  
Cereal Crops ◽  
Comprehensive Review ◽  
Spot Disease ◽  
The Past ◽  
Pyrenophora Tritici Repentis ◽  
Tan Spot Disease

Necrotrophic plant pathogens pose an important threat to crop production, and many fungi in the Pleosporales have caused the sudden emergence of major epidemics on cereal crops. Tan spot of wheat, caused by Pyrenophora tritici-repentis, is one example, and since its emergence in the 1970s, scientists have explored its virulence and interactions with the host. In this chapter, our aim is to provide a comprehensive review of the most significant landmarks in tan spot research over the past 50 years from a plant pathology perspective.

An inevitable crisis? From first to second year in counsellor training

2020 ◽  
Vol 5 (1) ◽  
pp. 74-89
Author(s):  
Hugh Crago
Keyword(s):  
Right Hemisphere ◽  
Training Programme ◽  
First Year ◽  
Training Experience ◽  
Counsellor Training ◽  
Student Dropout ◽  
Second Year ◽  
Neurological Research ◽  
First Year Of Life ◽  
And Control

In a seminal 1973 paper, Robert Clark described the very different “cultures” of the first and second year students in a four year clinical psychology PhD programme. The author applies Clark’s template to his own experiences as trainee or trainer in five different counsellor education programmes, one in the US and four in Australia. Each of the programmes, to varying degrees, demonstrates key features of the pattern identified by Clark, where the first year is “therapeutic” and other-oriented, the second is “professional” and self-focused. The author concludes that all the surveyed programmes exhibited some level of “second year crisis”, in which a significant number of students felt abandoned, dissatisfied, or rebellious. The author extends and refines Clark’s developmental analogy (first year = childhood; second year = adolescence) to reflect recent neurological research, in particular, the shift from a right hemisphere-dominant first year of life, prioritising affiliative needs, to a left hemisphere-dominant second year, prioritising autonomy and control. This shift is paralleled later by a more gradual move from a protective, supportive childhood to necessary, but sometimes conflictual, individuation in adolescence. The first two years of a counsellor training programme broadly echo this process, a process exacerbated by the second year internship/placement, in which students must “leave home” and adjust to unfamiliar, potentially less nurturing, authority figures. Finally, the author suggests introducing more rigorous “academic holding” into the first year, and greater attention to “therapeutic holding” of dissident students in the second, hopefully decreasing student dropout, and achieving a better balanced training experience.

THE EFFECT OF APPLYING ANIMAL CARTOON PICTURES ON STUDENTS’ ACHIEVEMENT IN WRITING NARRATIVE TEXT

2017 ◽  
Vol 6 (1) ◽  
Author(s):  
Hasanul Arifin Zul And Masitowarni Siregar
Keyword(s):  
T Test ◽  
Narrative Text ◽  
Control Group ◽  
First Year ◽  
Writing Achievement ◽  
Control Groups ◽  
Post Test ◽  
Written Test ◽  
And Control ◽  
Experimental Group

This thesis is focused on the investigation of the effect of applying animal cartoon pictures on students’ achievement in writing narrative text. This study aims to find whether applying animal cartoon pictures significantly affect the students’ writing achievement or not. The data in this study were obtained by administering a written test. The population was the 2015/2016 first year (grade XI) of SMA Swasta Nusantara Lubuk Pakam and 66 students were taken as the sample by using random sampling. The sample was divided into two groups, experimental and control groups. The experimental group was taught by applying animal cartoon pictures while the control group without animal cartoon pictures (x = lecturing). The data were taken the scores from the pre-test and post-test to both experimental and control groups. These data were analyzed by using t-test. The result of computing the t-test obviously showed that t-observed is higher than t-table (5.21 >1,67) with the degree of freedom 64 (df =N-2) at the level significance 0,05 one tail test. It showed that the application of animal cartoon pictures significantly affected the students of SMA Swasta Nusantara Lubuk Pakam achievement in writing narrative text.

scholarly journals ‘Children Are to Be Regarded as Propaganda’: Contradictions of German Occupation Policies in the Child Evacuations to Switzerland, 1941–1942

2021 ◽  
Vol 51 (1) ◽  
pp. 76-97
Author(s):  
Chelsea Sambells
Keyword(s):  
First Year ◽  
German Occupation ◽  
Nazi Occupation ◽  
And Control

During the first year of Nazi occupation in Belgium, the German authorities consented to send thousands of hungry children to neutral Switzerland for three-month periods of recuperation by means of a Swiss-operated evacuation scheme. After Nazi officials in Berlin learned of these unusual evacuations, the German occupation authorities in Belgium became embroiled in defending and justifying their actions. This article argues that while such contradictions and paradoxes in occupation policies epitomized the Nazi leadership, both the value and agency of children – and the perception of saving them – became unconventional Nazi weapons of exploitation and control.

scholarly journals Evaluation of a Novel Molecular Marker Associated with the Tan Spot Disease Response in Wheat

Agriculture ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 513
Author(s):  
Pao Theen See ◽  
Caroline S. Moffat
Keyword(s):  
Molecular Marker ◽  
Hexaploid Wheat ◽  
Wheat Breeding ◽  
Tan Spot ◽  
Growth Stages ◽  
Disease Score ◽  
Wheat Varieties ◽  
Disease Response ◽  
Spot Disease ◽  
Tan Spot Disease

After nearly 40 years of DNA molecular marker development in plant breeding, the wheat research community has amassed an extensive collection of molecular markers which have been widely and successfully used for selection of agronomic, physiological and disease resistance traits in wheat breeding programs. Tan spot is a major fungal disease of wheat and a significant global economic challenge and is caused by the necrotrophic fungal pathogen Pyrenophora tritici-repentis (Ptr). Here, the potential for using a PCR-based marker (Ta1AS3422) present on the short arm of wheat chromosome 1A, was evaluated for effectiveness in distinguishing tan spot disease susceptibility. The marker was initially screened against 40 commercial Australian hexaploid wheat varieties, and those that amplified the marker had an overall lower disease score (2.8 ± 0.7 for seedlings and 2.4 ± 0.4 for plants at the tillering stage), compared to those lacking the marker which exhibited a higher disease score (3.6 ± 0.8 for both growth stages). The potential of Ta1AS3422 as a marker for the tan spot disease response was further assessed against a panel of 100 commercial Australian hexaploid wheat varieties. A significant association was observed between marker absence/presence and tan spot disease rating (Pearson’s chi-squared test, χ2 (6) = 20.53, p = 0.002), with absence of Ta1AS3422 associated with susceptibility. This simple and cost-effective PCR-based marker may be useful for varietal improvement against tan spot, although further work is required to validate its effectiveness.

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