scholarly journals Laminarin Induces Defense Responses and Efficiently Controls Olive Leaf Spot Disease in Olive

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1043
Author(s):  
George T. Tziros ◽  
Anastasios Samaras ◽  
George S. Karaoglanidis
Keyword(s):  
Leaf Spot ◽  
Defense Responses ◽  
Copper Accumulation ◽  
Leaf Spot Disease ◽  
Biological Control Agents ◽  
Olive Leaf ◽  
Control Efficacy ◽  
Resistance Inducers ◽  
Kinetics Of ◽  
Potential Use

Olive leaf spot (OLS) caused by Fusicladiumoleagineum is mainly controlled using copper fungicides. However, the replacement of copper-based products with eco-friendly alternatives is a priority. The use of plant resistance-inducers (PRIs) or biological control agents (BCAs) could contribute in this direction. In this study we investigated the potential use of three PRIs (laminarin, acibenzolar-S-methyl, harpin) and a BCA (Bacillus amyloliquefaciens FZB24) for the management of OLS. The tested products provided control efficacy higher than 68%. In most cases, dual applications provided higher (p < 0.05) control efficacies compared to that achieved by single applications. The highest control efficacy of 100% was achieved by laminarin. Expression analysis of the selected genes by RT-qPCR revealed different kinetics of induction. In laminarin-treated plants, for most of the tested genes a higher induction rate (p < 0.05) was observed at 3 days post application. Pal, Lox, Cuao and Mpol were the genes with the higher inductions in laminarin-treated and artificially inoculated plants. The results of this study are expected to contribute towards a better understanding of PRIs in olive culture and the optimization of OLS control, while they provide evidence for potential contributions in the reduction of copper accumulation in the environment.

scholarly journals Identification of Genetic Markers in Olive Linked to Olive Leaf Spot Resistance and Susceptibility

2001 ◽  
Vol 126 (3) ◽  
pp. 305-308 ◽  
Author(s):  
Genet Teshome Mekuria ◽  
Graham Collins ◽  
Margaret Sedgley ◽  
Shimon Lavee
Keyword(s):  
Leaf Spot ◽  
Bulked Segregant Analysis ◽  
Screening Tools ◽  
Leaf Spot Disease ◽  
Olive Leaf ◽  
Base Pairs ◽  
Spot Disease ◽  
Susceptible Bulk ◽  
Improvement Programs ◽  
Segregating Population

Olive leaf spot is a disease of olive (Olea europaea L.) caused by the fungal pathogen, Spilocea oleaginea Cast. Progeny derived from crosses among susceptible, resistant, and semiresistant parental lines were assessed in the field for 8 years and classified as either resistant or susceptible. DNA from some of the progeny of this segregating population was used to identify molecular markers linked to olive leaf spot disease using the randomly amplified polymorphic DNA (RAPD) technique and bulked segregant analysis (BSA). Two DNA bulks were constructed, each containing 13 progeny showing either resistance or susceptibility for the disease, and screened for polymorphisms using 100 primers. One primer produced two polymorphic bands, one of ≈700 base pairs (bp) from the susceptible bulk and the other of ≈780 bp from the resistant bulk. The 780 bp marker appeared in 70.6% of the segregating progeny and 100% of parents showing resistance to leaf spot disease, while the 700 bp marker appeared in 47.1% of the segregating progeny and 100% of the parents showing susceptibility. These markers can be used as screening tools in olive improvement programs.

scholarly journals Sources of variation in a field evaluation of the incidence and severity of olive leaf spot

2005 ◽  
Vol 58 ◽  
pp. 273-277 ◽  
Author(s):  
E.O. Obanor ◽  
M. Walter ◽  
E.E. Jones ◽  
M.V. Jaspers
Keyword(s):  
Leaf Spot ◽  
Disease Incidence ◽  
Field Evaluation ◽  
Leaf Spot Disease ◽  
Olive Leaf ◽  
Mean Values ◽  
Spot Disease ◽  
Sources Of Variation ◽  
The Mean ◽  
Over Time

Incidence ( infected leaves) and severity (number of lesions/leaf) of olive leaf spot disease caused by Spilocaea oleagina were assessed every 2 weeks on 20 trees in a Canterbury olive grove for 12 weeks during summer 2003/04 All the trees were infected by olive leaf spot disease (OLS) and although disease incidence and severity varied between trees (Plt;0001) it did not vary between branches over time (P0088) There was a strong correlation (R20869) between disease incidence and severity It was estimated that at least five trees and 50 leaves/tree were required to correctly estimate the mean values of the parameters measured Throughout the duration of the experiment no new leaf lesions formed and although old lesions increased in size (Plt;0001) spore numbers decreased from 5104 to 1102 conidia/cm2 of lesion and viability of conidia declined from 55 to 10

Biological control of Peacock spot disease caused by Spilocaea oleagina on Olive using bacteria.

2020 ◽  
Vol 8 (1) ◽  
pp. 12-20
Author(s):  
Mazen Salman
Keyword(s):  
Leaf Spot ◽  
Latent Infection ◽  
Conidial Germination ◽  
Leaf Spot Disease ◽  
Olive Leaf ◽  
Olive Leaves ◽  
Spot Disease ◽  
Before And After ◽  
Olive Trees ◽  
Chemical Fungicides

The olive leaf spot disease caused by the fungus Spilocaea oleagina (Cast.) Hughes (syn. Cycloconium oleagina) is one of the most destructive diseases on olive trees causing losses that may reach 20% of the yield. The disease is controlled by the application of chemical fungicides which is not always feasible in providing proper protection against the pathogen. In this work we report the efficacy of Pseudomonas fluorescenc isolate ORS3 and Bascillus atrophaeus isolate Bat in controlling the disease under field conditions. An Olive field in, Tulkarm governorate, Palestine was selected. The olive trees were 5-10 years old and were highly infected with the olive leaf spot. Trees were sprayed with bacteria formulated in oil. Control trees were sprayed with water. For evaluation of bacterial efficacy against the disease, olive leaves were collected before and after application of the bacteria. Germination of conidia latent infection and severity were determined. In addition to that, bacterial viability was assessed. Results of the work revealed that the bacteria were able to inhibit conidial germination of the fungus. The percent of reduction in conidial germination (85.8 and 70.2%) in the presence of P. fluorescenc isolate ORS and B. atrophaeus isolate Bat, respectively was significantly lower than that in the control or in leaves sprayed with 10% oil (69.1 and 56.1%, respectively). After two weeks of spraying, the percent of latent infectoin (figure 4) was significantly (p<0.05) lower on leaves sprayed with P. fluorescenc isolate ORS3 and B. atrophaeus isolate BAT (5.1 and 3.8% latent infection, respectively). However, bacterial shelf life on the surface of olive leaves was reduced after three days of spraying (i.e no bacteria were re-isolated). The results indicated that the bacteria can be used for control of the leaf spot disease. Further studies are required to evaluate the efficacy of the bacteria under different environmental conditions.

Efficacy of systemic acquired resistance inducers in olive leaf spot management

2012 ◽  
Vol 42 (2) ◽  
pp. 163-168 ◽  
Author(s):  
Friday O. Obanor ◽  
Monika Walter ◽  
E. Eirian Jones ◽  
Marlene V. Jaspers
Keyword(s):  
Leaf Spot ◽  
Systemic Acquired Resistance ◽  
Acquired Resistance ◽  
Olive Leaf ◽  
Resistance Inducers

scholarly journals Disease Severity of Angular Leaf Spot Disease by Different Inoculation Method and Eco-Friendly Control Efficacy in Strawberry.

2016 ◽  
Vol 20 (1) ◽  
pp. 35-40
Author(s):  
Da-Ran Kim ◽  
Gun-hye Gang ◽  
Hyun-ji Cho ◽  
Hae-Suk Yoon ◽  
In Sik Myoung ◽  
...  
Keyword(s):  
Disease Severity ◽  
Leaf Spot ◽  
Angular Leaf Spot ◽  
Leaf Spot Disease ◽  
Control Efficacy ◽  
Spot Disease ◽  
Inoculation Method

scholarly journals Evaluation of susceptibility of an olive progeny (Picholine x Meski) to olive leaf spot disease caused by Fusicladium oleagineum

2012 ◽  
Vol 135 (1) ◽  
pp. 23-33 ◽  
Author(s):  
A. Rhouma ◽  
M. Chettaoui ◽  
S. Krid ◽  
H. Elbsir ◽  
M. Msallem ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Leaf Spot Disease ◽  
Olive Leaf ◽  
Spot Disease

Biological control of Peacock spot disease caused by Spilocaea oleagina on Olive using bacteria.

2020 ◽  
Vol 8 (1) ◽  
pp. 12-20
Author(s):  
Mazen Salman
Keyword(s):  
Leaf Spot ◽  
Latent Infection ◽  
Conidial Germination ◽  
Leaf Spot Disease ◽  
Olive Leaf ◽  
Olive Leaves ◽  
Spot Disease ◽  
Before And After ◽  
Olive Trees ◽  
Chemical Fungicides

The olive leaf spot disease caused by the fungus Spilocaea oleagina (Cast.) Hughes (syn. Cycloconium oleagina) is one of the most destructive diseases on olive trees causing losses that may reach 20% of the yield. The disease is controlled by the application of chemical fungicides which is not always feasible in providing proper protection against the pathogen. In this work we report the efficacy of Pseudomonas fluorescenc isolate ORS3 and Bascillus atrophaeus isolate Bat in controlling the disease under field conditions. An Olive field in, Tulkarm governorate, Palestine was selected. The olive trees were 5-10 years old and were highly infected with the olive leaf spot. Trees were sprayed with bacteria formulated in oil. Control trees were sprayed with water. For evaluation of bacterial efficacy against the disease, olive leaves were collected before and after application of the bacteria. Germination of conidia latent infection and severity were determined. In addition to that, bacterial viability was assessed. Results of the work revealed that the bacteria were able to inhibit conidial germination of the fungus. The percent of reduction in conidial germination (85.8 and 70.2%) in the presence of P. fluorescenc isolate ORS and B. atrophaeus isolate Bat, respectively was significantly lower than that in the control or in leaves sprayed with 10% oil (69.1 and 56.1%, respectively). After two weeks of spraying, the percent of latent infectoin (figure 4) was significantly (p<0.05) lower on leaves sprayed with P. fluorescenc isolate ORS3 and B. atrophaeus isolate BAT (5.1 and 3.8% latent infection, respectively). However, bacterial shelf life on the surface of olive leaves was reduced after three days of spraying (i.e no bacteria were re-isolated). The results indicated that the bacteria can be used for control of the leaf spot disease. Further studies are required to evaluate the efficacy of the bacteria under different environmental conditions.

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