Effects of host plant resistance and fungicide applications on Ascochyta blight symptomology and yield of chickpea (Cicer arietinum L.).

Plant Disease ◽  
2021 ◽  
Author(s):  
Frankie Crutcher ◽  
Yesuf Assen Mohammed ◽  
Chengci Chen ◽  
Sherry Turner
Keyword(s):  
Ascochyta Blight ◽  
Ascochyta Rabiei ◽  
Yield Losses ◽  
Management Options ◽  
Resistant Cultivars ◽  
Fungicide Application ◽  
The Mean ◽  
Control Disease ◽  
Moderately Resistant ◽  
Chickpea Cultivars

Ascochyta blight (AB), caused by the pathogen Ascochyta rabiei, is a major threat to chickpea production worldwide causing major yield losses and decreasing quality. Control of AB requires integrating pest management options including resistant cultivars and fungicide applications. To address this, fungicides with different modes of action were evaluated on three chickpea cultivars with differing levels of susceptibility to AB under irrigated and dryland conditions in 2015 to 2017. The fungicides were applied once or twice and compared to a no fungicide application control on AB score and yield. The mean grain yields across locations and years were 1753, 1283 and 981 kg/ha, with a corresponding AB mean score of 2.6, 3.2, and 3.3 on 0 to 7 scale (where 0 is no disease and 7 is completely dead) for the moderately resistant, moderately susceptible, and susceptible chickpea cultivars, respectively. Fungicide application was not enough to control disease throughout the season. The use of AB resistant cultivars had the most significant impact on minimizing the disease and maximizing yield, irrespective of year and location. This study supports previous research indicating that planting AB resistant chickpea cultivars is essential for disease control, regardless of the fungicides applied.

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 Age-Dependent Resistance toRhizoctonia solaniin Sugar Beet

Plant Disease ◽  
2019 ◽  
Vol 103 (9) ◽  
pp. 2322-2329 ◽  
Author(s):  
Yangxi Liu ◽  
Aiming Qi ◽  
Mohamed F. R. Khan
Keyword(s):  
Sugar Beet ◽  
Seed Treatment ◽  
Age Groups ◽  
Plant Age ◽  
Resistant Cultivars ◽  
Fungicide Application ◽  
Greenhouse Study ◽  
Crown And Root Rot ◽  
Barley Grains ◽  
Moderately Resistant

Rhizoctonia crown and root rot of sugar beet (Beta vulgaris L.), caused by Rhizoctonia solani, continues to be one of the important concerns for the beet industry in Minnesota and North Dakota. Use of resistant cultivars is an important strategy in the management of R. solani in combination with seed treatment and timely fungicide application during the growing season. The objective of this greenhouse study was to determine how sugar beet plants responded to increasing age in resistance to R. solani. Each of three seed companies provided three commercial cultivars with varying R. solani resistance levels: susceptible, moderately resistant, and resistant. Seed were planted at a weekly interval to create different plant age groups from seed to 10-week-old plants, with growing degree days (GDD) ranging from 0 to 1,519 thermal time (°Cd). Seed and plants were all simultaneously inoculated with R. solani AG2-2-infested barley grains. Twenty-eight days after inoculation, plants were pulled and washed, and roots were evaluated for disease severity. All cultivars were highly susceptible to R. solani when inoculated at seed to 3 weeks old (0 to 464°Cd). At 4 and 5 weeks of plant age (617 to 766°Cd), resistant cultivars started to show significant resistance to R. solani. Proportion of the affected roots with disease score ≥ 5 followed a sigmoid response, declining with increased GDD in moderately resistant and resistant cultivars, whereas it continued to decline linearly with increased GDD in susceptible cultivars. This study demonstrated that sugar beet cultivars, regardless of their assigned level of R. solani resistance, were highly susceptible to the pathogen before they reached the six- to eight-leaf stage at 4 to 5 weeks (617 to 766°Cd) after planting. Therefore, additional protection in the form of seed treatment or fungicide application may be required to protect sensitive sugar beet seed and seedlings in fields with a history of R. solani under favorable environmental conditions.

scholarly journals Identification of novel sources of resistance to ascochyta blight in a collection of wild Cicer accessions

2020 ◽  
Author(s):  
Toby E. Newman ◽  
Silke Jacques ◽  
Christy Grime ◽  
Fiona L. Kamphuis ◽  
Robert C. Lee ◽  
...  
Keyword(s):  
Genome Wide Association Study ◽  
Ascochyta Blight ◽  
Ascochyta Rabiei ◽  
Sources Of Resistance ◽  
Highly Pathogenic ◽  
Cicer Echinospermum ◽  
Genome Wide ◽  
A Genome ◽  
The Impact ◽  
Chickpea Cultivars

Chickpea production is constrained worldwide by the necrotrophic fungal pathogen Ascochyta rabiei, the causal agent of ascochyta blight (AB). In order to reduce the impact of this disease, novel sources of resistance are required in chickpea cultivars. Here, we screened a new collection of wild Cicer accessions for AB resistance and identified accessions resistant to multiple, highly pathogenic isolates. In addition to this, analyses demonstrated that some collection sites of Cicer echinospermum harbour predominantly resistant accessions, knowledge that can inform future collection missions. Furthermore, a genome-wide association study identified regions of the Cicer reticulatum genome associated with AB resistance and investigation of these regions identified candidate resistance genes. Taken together, these results can be utilised to enhance the resistance of chickpea cultivars to this globally yield-limiting disease.

Sensitivity of field populations of Ascochyta rabiei to chlorothalonil, mancozeb and pyraclostrobin fungicides and effect of strobilurin fungicides on the progress of ascochyta blight of chickpea

2007 ◽  
Vol 87 (4) ◽  
pp. 937-944 ◽  
Author(s):  
K. F. Chang ◽  
H. U. Ahmed ◽  
S. F. Hwang ◽  
B. D. Gossen ◽  
S. E. Strelkov ◽  
...  
Keyword(s):  
Ascochyta Blight ◽  
Ascochyta Rabiei ◽  
Growth Media ◽  
Single Spore ◽  
Fungicide Application ◽  
Strobilurin Fungicides ◽  
Cultural Measures ◽  
Fungicide Tolerance ◽  
Total Crop ◽  
Fungicide Insensitivity

Chickpea production faces a major challenge from ascochyta blight (Ascochyta rabiei), a devastating disease that can cause total crop loss. To assess the effect of repeated fungicide application on disease progress, strobilurin fungicides, primarily alternating pyraclostrobin and azoxystrobin treatments, were applied up to five times per year in each of 2 yr. A single application or two early applications reduced blight severity. A third application resulted in additional benefits in 1 of 2 yr, but additional applications did not reduce severity further. To monitor for fungicide tolerance in populations of A. rabiei, 66 single- spore isolates were collected and grown on growth media amended with chlorothalonil, mancozeb, or pyraclostrobin. Insensitivity to one or more of the fungicides was detected in 49 (74%) of the isolates. Based on the effect on conidial germination, insensitivity to pyraclostrobin or chlorothalonil was observed in 26 of 37 isolates (70%). Repeated fungicide application may be selecting for insensitive isolates of the pathogen; fungicide application should be combined with cultural measures to control ascochyta blight. Key words: Fungicide insensitivity, Ascochyta rabiei

scholarly journals Ascochyta blight of chickpea (Cicer arietinum L.): a review of biology, pathogenicity, and disease management

2005 ◽  
Vol 56 (4) ◽  
pp. 317 ◽  
Author(s):  
S. Pande ◽  
K. H. M. Siddique ◽  
G. K. Kishore ◽  
B. Bayaa ◽  
P. M. Gaur ◽  
...  
Keyword(s):  
Cicer Arietinum ◽  
Foliar Application ◽  
Ascochyta Blight ◽  
Management Strategies ◽  
Hydrolytic Enzymes ◽  
Research Priorities ◽  
Ascochyta Rabiei ◽  
Future Research ◽  
Management Options ◽  
Cicer Arietinum L

Ascochyta blight (AB), caused by Ascochyta rabiei is a major disease of chickpea (Cicer arietinum L.), especially in areas where cool, cloudy, and humid weather persists during the crop season. Several epidemics of AB causing complete yield loss have been reported. The fungus mainly survives between seasons through infected seed and in infected crop debris. Despite extensive pathological and molecular studies, the nature and extent of pathogenic variability in A. rabiei have not been clearly established. Accumulation of phenols, phytoalexins (medicarpin and maackiain), and hydrolytic enzymes has been associated with host-plant resistance (HPR). Seed treatment and foliar application of fungicides are commonly recommended for AB management, but further information on biology and survival of A. rabiei is needed to devise more effective management strategies. Recent studies on inheritance of AB resistance indicate that several quantitative trait loci (QTLs) control resistance. In this paper we review the biology of A. rabiei, HPR, and management options, with an emphasis on future research priorities.

scholarly journals Evidence of recent increased pathogenicity within the Australian Ascochyta rabiei population

2020 ◽  
Author(s):  
P Sambasivam ◽  
Y Mehmood ◽  
I Bar ◽  
J Davidson ◽  
K Hobson ◽  
...  
Keyword(s):  
Control Strategies ◽  
Severe Disease ◽  
Ascochyta Blight ◽  
Resistant Cultivar ◽  
Ascochyta Rabiei ◽  
Application Timing ◽  
Defence Responses ◽  
Moderately Resistant ◽  
Resistant Genotypes ◽  
Resistance Rating

AbstractAscochyta Blight (AB), caused by Ascochyta rabiei (syn Phoma rabiei), is the major endemic foliar fungal disease affecting the Australian chickpea industry, resulting with potential crop loss and management costs. This study was conducted to better understand the risk posed by the Australian A. rabiei population to current resistance sources and to provide informed decision support for chemical control strategies. Recent changes in the pathogenicity of the population were proposed based on disease severity and histopathological observations on a host set. Controlled environment disease screening of 201 isolates on the host set revealed distinct pathogenicity groups, with 41% of all isolates assessed as highly aggressive and a significant increase in the proportion of isolates able to cause severe damage on resistant and moderately resistant cultivars since 2013. In particular, the frequency of highly aggressive isolates on the widely adopted PBA HatTrick cultivar rose from 18% in 2013 to 68% in 2017. In addition, isolates collected since 2016 caused severe disease on Genesis 090, another widely adopted moderately resistant cultivar and on ICC3996, a commonly used resistance source. Of immediate concern was the 10% of highly aggressive isolates able to severely damage the recently released resistant cultivar PBA Seamer (2016). Histopathology studies revealed that the most aggressive isolates were able to germinate, develop appressoria and invade directly through the epidermis faster than lower aggressive isolates on all hosts assessed, including ICC3996. The fungal invasion triggered a common reactive oxygen species (ROS) and hypersensitive response (HR) on all assessed resistant genotypes with initial biochemical and subsequent structural defence responses initiated within 24 hours of inoculation by the most highly aggressive isolates. These responses were much faster on the less resistant and fastest on the susceptible check host, indicating that speed of recognition was correlated with resistance rating. This will inform fungicide application timing so that infected crops are sprayed with prophylactic chemistries prior to invasion and with systemic chemistries after the pathogen has invaded.

scholarly journals Common Ragweed (Ambrosia artemisiifolia L.) Causes Severe Yield Losses in Soybean and Impairs Bradyrhizobium japonicum Infection

Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1616
Author(s):  
Rea Maria Hall ◽  
Bernhard Urban ◽  
Helmut Wagentristl ◽  
Gerhard Karrer ◽  
Anna Winter ◽  
...  
Keyword(s):  
Bradyrhizobium Japonicum ◽  
Yield Loss ◽  
Chemical Compounds ◽  
Ambrosia Artemisiifolia ◽  
Yield Losses ◽  
Management Options ◽  
Soybean Yield ◽  
Common Ragweed ◽  
Arable Fields ◽  
The Mean

Ambrosia artemisiifolia L. (Asteraceae), known as common ragweed, is an annual herbaceous species native to North America that has become one of the most economically important weeds in arable fields throughout Central Europe. Its large ecological amplitude enables the species to become established in several types of environments, and management options to effectively contain its spread are limited due to a lack of efficacy, high cost, or lack of awareness. In the last decade, in particular, soybean fields have been severely affected by common ragweed invasion. However, until now, information on the yield-decreasing effects of the plant has been scarce. Therefore, the aim of this study was to evaluate the competition effects of common ragweed on (1) soybean growth (aboveground/belowground), (2) the yield of two different soybean cultivars, and (3) the nodulation potential. Based on a greenhouse and biennial field trial, we found that in plots with the highest common ragweed biomass, the soybean yield loss accounted for 84% compared to the weed-free control, on average. The number of nodules, in addition to the mean nodule weight, which are tightly correlated with soybean yield, were significantly reduced by the presence of common ragweed. Just one common ragweed plant per square meter reduced the number of nodules by 56%, and consequently led to a decrease in yield of 18%. Although it has been reported that the genus Ambrosia produces and releases several types of secondary metabolites, little is known about the influence of these chemical compounds on soybean growth and nodulation. Thus, there is substantial need for research to understand the mechanisms behind the interaction between common ragweed and soybean, with a view to finding new approaches for improved common ragweed control, thereby protecting soybean and other crops against substantial yield losses.

Characterization of resistance to ascochyta blight of selected wild Cicer germplasm

Botany ◽  
2015 ◽  
Vol 93 (11) ◽  
pp. 723-734 ◽  
Author(s):  
Cheryl Armstrong-Cho ◽  
Monika M. Lulsdorf ◽  
Parvaneh Hashemi ◽  
Sabine Banniza
Keyword(s):  
Ascochyta Blight ◽  
Hyphal Growth ◽  
Ascochyta Rabiei ◽  
Symptom Development ◽  
Infection Rates ◽  
Resistant Genotype ◽  
Pathogen Colonization ◽  
Hydrogen Peroxide Generation ◽  
Chickpea Cultivars

The resistance of 24 perennial Cicer accessions to Ascochyta rabiei (Pass.) Labr. was assessed under field and greenhouse conditions. Two perennial and two annual Cicer accessions with superior resistance were examined and compared with susceptible (‘CDC Xena’) and resistant (‘CDC Frontier’) domesticated Cicer arietinum L. (chickpea) cultivars in terms of pathogen colonization, symptom development, host autofluorescence, and hydrogen peroxide generation. Colonizing hyphae on the four wild Cicer genotypes were pigmented, but hyaline on cultivated chickpea. The morphology of colonizing hyphae differed on the six genotypes, with wider hyphae observed on the most resistant genotype, Cicer anatolicum Alef. PI 383626. Inoculation of leaves of the top five nodes indicated that infection rates were highest on the youngest unfurled leaf for C. anatolicum PI 383626, Cicer oxyodon Boiss. & Hoh. PI 561103, Cicer bijugum Rech.f. ILWC 260, and ‘CDC Frontier’. Observations of hyphal pigmentation, modified hyphal growth, and low infection rates on fully developed leaves of wild Cicer plants suggest that components of the plant surface play an important role in disease resistance. Localized autofluorescence in response to infection was observed in the two perennials, but not in the other genotypes examined. The distinct resistance strategy observed in these perennial accessions make them interesting but challenging candidates for introgression of resistance into cultivated chickpea.

Beef production from native pastures sown to fine-stem stylo in the Burnett region of south-eastern Queensland

1979 ◽  
Vol 19 (97) ◽  
pp. 140 ◽  
Author(s):  
EJ Bowen ◽  
KG Rickert
Keyword(s):  
Stocking Rate ◽  
Management Options ◽  
North West ◽  
Heteropogon Contortus ◽  
South Eastern ◽  
Continuous Grazing ◽  
Weight Gains ◽  
The Mean ◽  
Native Pastures ◽  
Stocking Rates

At Gayndah, south-eastern Queensland, a native Heteropogon contortus pasture, sown to fine-stem stylo (Stylosanthes guianensis var. intermedia), and invaded by red natal grass (Rhynchelytrum repens), was grazed by weaner steers from June 1 in three treatments : heavy and light put-and-take grazing for five years from 1971, and set-stocked at 1.37 animals ha-1 for two years from 1974. Weight gains in the put-and-take treatments were not significantly different. The mean annual liveweight gain was 167 kg animal-1 at a mean equivalent stocking rate of 1.47 animals ha-1. Over the same period unsown native pasture, cleared of timber, gave a gain of 62 kg animal-1 at 0.62 animals ha-1. In all seasons except summer, weight gains declined linearly with stocking rate and in 1972-73, with a mean equivalent stocking rate of 2.66 animals ha-1, the annual gain was almost halved. When equivalent stocking rates were 0.9, 0.9, 1.8 and 1.2 animals ha-1 in winter, spring, summer and autumn, the respective gains were 4, 73, 65 and 45 kg animal-1. The set-stocked treatment had a mean annual gain of 147 kg animal-1. At another site 116 km north-west of Gayndah, two paddocks of Heteropogon contortus and fine-stem stylo were set-stocked with weaners over four years. One paddock had four applications of superphosphate of 250 kg ha-1. The mean annual liveweight gains were significantly different, being 154 and 143 kg animal-1 in the fertilized and unfertilized paddocks at mean stocking rates of 0.83 and 0.74 animals ha-1, respectively. In a grazing protection experiment the density of fine-stem stylo declined exponentially with an accumulation of pasture dry matter in spring and summer. Heavy continuous grazing, an annual hay cut and an accidental fire all increased the density of fine-stem stylo. Management options to maintain the density of fine-stem stylo and the relative importance of the legume and grass to animal production are discussed.

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