scholarly journals Role of weather factors in development of late leaf spot (Phaeoisariopsis personata) on groundnut (Arachis hypogaea)

MAUSAM ◽  
2021 ◽  
Vol 68 (2) ◽  
pp. 299-308
Author(s):  
UTPAL DEY ◽  
D. N. DHUTRAJ ◽  
DIGANGGANA TALUKDAR ◽  
ANUP DAS

The field experiment was conducted during Kharif 2012 and 2013 to find out the influence of weather parameters viz., temperature, relative humidity, rainfall, rainy days and wind velocity on the intensity of late leaf spot disease and defoliation in four groundnut cultivars viz., JL-24, LGN-1, TAG-24 and TG-26. The prevailing weather condition viz., average temperatures of 30.92 °C (max.) and 22.31 °C (min.), average RH of 89.67 % (morning) and 64.25 % (evening), well distributed average rainfall of 50.33 mm, average rainy days of 2.67 and average wind velocity of 4.24 km/hr were found to be conducive for the initiation, development and spread of late leaf spot disease in susceptible groundnut Cv. JL-24, TAG-24 and tolerant Cv. LGN-1, TG-26. As a result, overall average maximum disease intensity of 33.97 (21.96 to 46.37 %) per cent and 29.06 (18.62 to 39.01 %) per cent, were recorded in JL-24 and TAG-24, respectively. Groundnut Cv. JL-24 and TAG-24 (susceptible) exhibited comparatively maximum average defoliation in the range of 6.65 to 14.05 (Av. 10.29 %) and 5.64 to 11.82 per cent (Av. 8.80 %), respectively. The correlation coefficient between weather variables and disease intensity in both the years indicated that maximum temperature had negative and non significant effect in all the groundnut cultivars; whereas, minimum temperature had positive and significant effect on the disease intensity in all the groundnut cultivars. Relative humidity (morning and evening) played significant positive role on the disease intensity in all the groundnut cultivars.  

Author(s):  
Ye Chu ◽  
H. Thomas Stalker ◽  
Kathleen Marasigan ◽  
Chandler M. Levinson ◽  
Dongying Gao ◽  
...  

Plant Disease ◽  
2001 ◽  
Vol 85 (8) ◽  
pp. 879-884 ◽  
Author(s):  
Shouan Zhang ◽  
M. S. Reddy ◽  
Nancy Kokalis-Burelle ◽  
Larry W. Wells ◽  
Stevan P. Nightengale ◽  
...  

A disease assay was optimized for late leaf spot disease of peanut using Cercosporidium per-sonatum in the greenhouse, and this assay was used in attempts to elicit induced systemic resistance using strains of plant growth-promoting rhizobacteria (PGPR) and chemical elicitors. Nineteen strains of spore-forming bacilli PGPR, including strains of Paenibacillus macerans, Brevibacillus brevis, Bacillus laterosporus, B. subtilis, B. pumilus, B. amyloliquefaciens, B. sphaericus, B. cereus, and B. pasteurii, which previously elicited systemic disease control activity on other crops, were evaluated in greenhouse assays. Seven PGPR strains elicited significant disease reduction in a single experiment; however, none repeated significant protection achieved in the greenhouse assay, while significant protection consistently occurred with the fungicide chlorothalonil (Bravo). In other greenhouse trials, neither stem injections of C. personatum nor foliar sprays of chemicals, including salicylic acid, sodium salicylate, isonicotinic acid, or benzo[1,2,3]thiadiazole-7-carbothioc acid S-methyl ester (Actigard), which elicit systemic acquired resistance on other crops, elicited significant disease protection. In contrast, foliar sprays with DL-β-amino-n-butyric acid (BABA), which is an elicitor of localized acquired resistance, resulted in significantly less late leaf spot disease in one of two tests. Combination treatments of four PGPR strains with BABA in the greenhouse did not significantly protect peanut from late leaf spot. Field trials conducted over two growing seasons indicated that none of the 19 PGPR strains, applied as seed treatments at two concentrations, significantly reduced late leaf spot disease. The same chemical elicitors tested in the greenhouse, including BABA, did not elicit significant disease protection. Some combinations of four PGPR and BABA significantly reduced the disease at one but not at two sample times. Collectively, these results suggest that late leaf spot resistance in peanut is not systemically inducible in the same manner as is resistance to diseases in other crops by PGPR and chemical inducers.


Author(s):  
M. K. Mahatma ◽  
Lokesh Kumar Thawait ◽  
K. S. Jadon ◽  
P. P. Thirumalaisamy ◽  
S. K. Bishi ◽  
...  

2014 ◽  
Vol 11 (2) ◽  
pp. 199-208
Author(s):  
MAH Khan ◽  
I Hossain

The effect of weather on prevalence of seedling diseases of coconut during 2010-11 and 2011-12 in different areas of Bangladesh was studied to develop an environment friendly disease management practice. Pestalotia palmarum was isolated and identified from leaf having spot. Incidence and severity of grey leaf spot at seedling stage were determined and significant variations were observed depending on weather factors as well as locations. Occurrence of seedling disease was significantly influenced by temperature, rainfall and relative humidity. Comparative effectiveness of BAU-Biofungicide either alone or in combination with two fungicides viz. Bavistin or Dithane M-45 was evaluated on coconut seedling in the nursery. Among the treatments applied, Trichoderma harzianum based BAU-Biofungicide either alone or in combination with Bavistin (0.2%) as an excellent biocontrol means in controlling leaf spot disease of coconut. DOI: http://dx.doi.org/10.3329/jbau.v11i2.19894 J. Bangladesh Agril. Univ. 11(2): 199-208, 2013


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