scholarly journals Epidemiology of the Groundnut (<i>Arachis hypogaea</i> L.) Leaf Spot Disease: Genetic Analysis and Developmental Cycles

2012 ◽  
Vol 03 (05) ◽  
pp. 582-588 ◽  
Author(s):  
L. Tshilenge-Lukanda ◽  
K. K. C. Nkongolo ◽  
A. Kalonji-Mbuyi ◽  
R. V. Kizungu
Keyword(s):  
Genetic Analysis ◽  
Arachis Hypogaea ◽  
Leaf Spot ◽  
Leaf Spot Disease ◽  
Spot Disease

scholarly journals Effects of Postemergence Herbicides on Cercospora arachidicola Hori and Early Leaf Spot of Peanut1

1999 ◽  
Vol 26 (1) ◽  
pp. 4-8 ◽  
Author(s):  
J. A. Baysinger ◽  
H. A. Melouk ◽  
D. S. Murray
Keyword(s):  
Arachis Hypogaea ◽  
Leaf Spot ◽  
Untreated Control ◽  
Conidial Germination ◽  
Leaf Spot Disease ◽  
Common Disease ◽  
Cercospora Arachidicola ◽  
Spot Disease ◽  
Arachis Hypogaea L ◽  
Postemergence Herbicides

Abstract Early leaf spot is a common disease of peanut caused by the fungus Cercospora arachidicola Hori. Experiments were conducted to evaluate the effect of postemergence herbicides on the conidial germination of C. arachidicola and on the incidence of early leaf spot disease in peanut (Arachis hypogaea L.) in a greenhouse. Conidial germination was enhanced (≥ 100%) at concentrations of 1, 100, and 1000 mg/L of 2,4-DB compared with the untreated control. Lactofen reduced conidial germination by 42% compared with the control at concentrations as low as 100 mg/L and completely inhibited germination at concentrations ≥ 5000 mg/L. A concentration of 10,000 mg/L acifluorfen and 2,4-DB completely inhibited conidial germination. Acifluorfen, acifluorfen plus 2,4-DB, and lactofen decreased the sporulation of early leaf spot lesions. Lactofen reduced leaf spot incidence 12% and decreased sporulation of lesions 22% compared with the control. None of the herbicides increased the incidence of early leaf spot on peanut plants or the number of early leaf spot lesions per leaflet when compared with plants that received no herbicide.

Peanut (Arachis hypogaea L.) Cultivar Response to Leaf Spot Disease Development Under Four Disease Management Programs1

1998 ◽  
Vol 25 (1) ◽  
pp. 35-39 ◽  
Author(s):  
W. J. Grichar ◽  
B. A. Besler ◽  
A. J. Jaks
Keyword(s):  
Arachis Hypogaea ◽  
Leaf Spot ◽  
Leaf Spot Disease ◽  
Cercospora Arachidicola ◽  
Spot Disease ◽  
Pod Yield ◽  
Leaf Spots ◽  
Arachis Hypogaea L ◽  
Yield Difference ◽  
Disease Pressure

Abstract Peanut (Arachis hypogaea L.) pod yield and response to early and late leaf spots [caused by Cercospora arachidicola S. Hori and Cercosporidium personatum (Berk. & M. A. Curtis) Deighton, respectively] were evaluated on six runner-type cultivars under four leaf spot spray programs using tebuconazole at 0.23 kg ai/ha and chlorothalonil at 1.26 kg ai/ha. The four leaf spot spray programs included unsprayed, 14-d schedule, 21-d schedule, and 28-d schedule. With the 14- and 21-d schedule, chlorothalonil was applied at the first and last applications with a maximum of four tebuconazole applications for the middle sprays. On the 28-d schedule, tebuconazole was applied four times. Under conditions of heavy leaf spot disease pressure where no fungicide was applied, Southern Runner and Georgia Browne were slightly less susceptible (although not significantly) to early or late leaf spot than Florunner, GK-7, Georgia Runner, or Sunrunner. Less leaf spot was present in the 14-d schedule compared to 21- or 28-d schedules. Although there was no yield difference between the 14-, 21-, or 28-d schedules, the plots sprayed on a 14-d schedule yielded 43% more than the unsprayed. When averaged across all spray schedules, Georgia Browne yielded 15% more peanuts than Georgia Runner.

scholarly journals Identification of Transcripts Involved in Resistance Responses to Leaf Spot Disease Caused by Cercosporidium personatum in Peanut (Arachis hypogaea)

2005 ◽  
Vol 95 (4) ◽  
pp. 381-387 ◽  
Author(s):  
M. Luo ◽  
P. Dang ◽  
M. G. Bausher ◽  
C. C. Holbrook ◽  
R. D. Lee ◽  
...  
Keyword(s):  
Gene Expression ◽  
Disease Resistance ◽  
Real Time ◽  
Arachis Hypogaea ◽  
Real Time Pcr ◽  
Leaf Spot ◽  
Leaf Spot Disease ◽  
Disease Resistance Gene ◽  
Cercosporidium Personatum ◽  
Spot Disease

Late leaf spot disease caused by Cercosporidium personatum is one of the most destructive foliar diseases of peanut (Arachis hypogaea) worldwide. The objective of this research was to identify resistance genes in response to leaf spot disease using microarray and real-time polymerase chain reaction (PCR). To identify transcripts involved in disease resistance, we studied the gene expression profiles in two peanut genotypes, resistant or susceptible to leaf spot disease, using cDNA microarray containing 384 unigenes selected from two expressed sequenced tag (EST) cDNA libraries challenged by abiotic and biotic stresses. A total of 112 spots representing 56 genes in several functional categories were detected as up-regulated genes (log2 ratio > 1). Seventeen of the top 20 genes, each matching gene with known function in GenBank, were selected for validation of their expression levels using real-time PCR. The two peanut genotypes were also used to study the functional analysis of these genes and the possible link of these genes to the disease resistance trait. Microarray technology and real-time PCR were used for comparison of gene expression. The selected genes identified by microarray analysis were validated by real-time PCR. These genes were more greatly expressed in the resistant genotype as a result of response to the challenge of C. personatum than in the susceptible genotype. Further investigations are needed to characterize each of these genes in disease resistance. Gene probes could then be developed for application in breeding programs for marker-assisted selection.

scholarly journals Analysis of Resistant Mechanisms in Groundnut Genotypes against Late Leaf Spot Disease

2021 ◽  
Vol 8 (7) ◽  
pp. 1-14
Author(s):  
K. Karunanithi ◽  
G. Senthilraja ◽  
K. Subrahmaniyan
Keyword(s):  
Arachis Hypogaea ◽  
Polyphenol Oxidase ◽  
Leaf Spot ◽  
Biochemical Parameters ◽  
Biochemical Analysis ◽  
Phenylalanine Ammonia Lyase ◽  
Leaf Spot Disease ◽  
Total Phenols ◽  
Late Leaf Spot ◽  
Spot Disease

Forty two groundnut (Arachis hypogaea) cultivars were screened for resistance to Phaeoisariopsispersonata under glasshouse conditions. Among them, two germplasms (VG19561 and VG19654) were found to have resistance against late leaf spot. Biochemical parameters such as, phenylalanine ammonia-lyase, peroxidase, polyphenol oxidase and total phenols were estimated among the resistant germplasms and susceptible check, VRI2. biochemical analysis revealed the increased activities of the enzymes viz., phenylalanine ammonia lyase, peroxidase, polyphenol oxidase, and phenolics in the resistant germplasms viz., VG19561 and VG19654 than the susceptible check, VRI 2.

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