scholarly journals Lack of Control of Citrus Canker by Induced Systemic Resistance Compounds

Plant Disease ◽  
2004 ◽  
Vol 88 (7) ◽  
pp. 745-750 ◽  
Author(s):  
J. H. Graham ◽  
R. P. Leite

Induced systemic resistance compounds (ISRs), acibenzolar-S-methyl (Actigard), and harpin protein (Messenger) were assayed in the greenhouse against Xanthomonas axonopodis pv. citrumelo, the cause of citrus bacterial spot (CBS), and X. axonopodis pv. citri, the cause of Asiatic citrus canker. Actigard and Messenger applied as foliar sprays 3 to 7 days before inoculation reduced numbers of lesions when either bacterium at 103 or 104 CFU/ml was injection-infiltrated into Swingle citrumelo leaves. Based on this activity, the ISRs were evaluated in southern Brazil in orchards of sweet oranges with low to moderate canker disease incidence in spray programs with and without copper oxychloride (COC) and copper hydroxide (CuOH). Actigard and Messenger were applied full season or in the first two or three sprays of a six-spray program in an attempt to reduce early canker disease on foliage and thereby reduce subsequent fruit infection and premature drop. Sprays of COC and CuOH were moderately to highly effective in reducing canker disease incidence and preventing premature fruit drop. Actigard or Messenger in combination with COC and CuOH, respectively, did not significantly reduce citrus canker incidence on foliage or fruit drop compared with Cu alone. The lack of additional control with ISRs means they cannot be recommended at this time to augment Cu programs for management of citrus canker.

Plant Disease ◽  
2017 ◽  
Vol 101 (5) ◽  
pp. 761-765 ◽  
Author(s):  
Yasser E. Ibrahim ◽  
Amgad A. Saleh ◽  
Mohammed A. Al-Saleh

Applications of formulated bacteriophages with skim milk and sucrose or nonformulated bacteriophages combined with acibenzolar-S-methyl (ASM) were compared with copper bactericides applications for suppressing Asiatic citrus canker (ACC) caused by Xanthomonas citri subsp. citri (Xcc) on leaves under greenhouse and field conditions in Saudi Arabia. Bacteriophages were applied one day prior to inoculation of Mexican lime (Citrus aurantifolia) plants with Xcc, then twice a week until the end of the trials. Copper hydroxide was applied once prior to inoculation and then every seven days afterward, whereas ASM was applied one week prior to inoculation and then every 21 days afterward. Under greenhouse conditions, the incidence of ACC on leaves was reduced significantly from 75.2 to 12.8% or 18.3% for plants treated with copper hydroxide or bacteriophages in combination with ASM, respectively. Applications of formulated phages in combination with ASM as soil drench under field conditions significantly decreased disease incidence by 14.8% (Trial 1) and 16.8% (Trial 2) compared with untreated control plants. Overall, the Xcc-inoculated plants treated with bacteriophages + ASM combination showed significant ACC reduction under greenhouse and field conditions. The bacteriophages + ASM combination tested in these trials can be an effective tool in the integrated management programs of Asiatic citrus canker disease.


Citrus canker is the most devastating bacterial disease. In Pakistan, where canker is endemic, cultural practices and chemical control is vital module of integrated management system. But due to non-prudent use of chemicals wicked impacts start to appear on human health and environment there was need of some alternative management which should be eco-friendly and has no adverse effect for human. Therefore, our present study was based on screening of different cultivars of citrus and allelopathic management of citrus canker. The results revealed that Cara cara navel and kinnow both performed as moderately susceptible response in field condition than all other cultivars of citrus in screening experiment. Consequently, disease incidence was observed increasing by increasing the lesion area and these cultivars can be suggested as a source of resistance against canker pathogen. In allelopathic management we observed that ethanolic extracts were more efficient than aqueous extracts and their efficacy was also increasing by increasing the concentration. Ethanolic extracts of jatropha (13.33cm) followed by amaltas (12.5cm), Arjun (11.13cm), Bougenvilla (7.21cm) have great potency against the pathogen. So these ethanolic extracts can be used as good and alternative management of citrus canker disease.


2008 ◽  
Vol 98 (7) ◽  
pp. 830-836 ◽  
Author(s):  
Yi-Hung Liu ◽  
Chien-Jui Huang ◽  
Chao-Ying Chen

Lily leaf blight, caused by Botrytis elliptica, is an important fungal disease in Taiwan. In order to identify an effective, nonfungicide method to decrease disease incidence in Lilium formosanum, the efficacy of rhizobacteria eliciting induced systemic resistance (ISR) was examined in this study. Over 300 rhizobacteria were isolated from the rhizosphere of L. formosanum healthy plants and 63 were identified by the analysis of fatty acid profiles. Disease suppressive ability of 13 strains was demonstrated by soil drench application of bacterial suspensions to the rhizosphere of L. formosanum seedlings. Biocontrol experiments were carried out with Bacillus cereus and Pseudomonas putida strains on L. formosanum and Lilium Oriental hybrid cvs. Acapulco and Star Gazer in greenhouse and field studies. Plants treated with B. cereus strain C1L showed that protection against B. elliptica on L. formosanum could last for at least 10 days and was consistent with high populations of B. cereus on lily roots. Analysis of the expression of LfGRP1 and LsGRP1, encoding glycine-rich protein associated with L. formosanum and cv. Star Gazer, respectively, revealed different responses induced by B. cereus or by the pathogen B. elliptica, suggesting that plant defense responses elicited by each follows a different signaling pathway. According to the results of biocontrol assays and LfGRP1/LsGRP1 gene expression analyses with culture filtrates of B. cereus strain C1L, we propose that eliciting factors of ISR are generated by B. cereus and some of them exhibit thermostable and heat-tolerant traits. This is the first report about ISR-eliciting rhizobacteria and factors effective for foliar disease suppression in lily.


2009 ◽  
Vol 35 (3) ◽  
pp. 191-195 ◽  
Author(s):  
Flávia Tavares Colpas ◽  
Kátia Regina Freitas Schwan-Estrada ◽  
José Renato Stangarlin ◽  
Maria De Lurdes Ferrarese ◽  
Carlos Alberto Scapim ◽  
...  

Aqueous extracts of the leaves of Ocimum gratissimum at 10, 25, 40 and 50% (w/v) concentrations induced the production of phytoalexins in soybean cotyledons and sorghum mesocotyls. The aqueous extracts also induced systemic resistance in cucumber to Colletotrichum lagenarium, reflected by reduction in disease incidence and an increase in chitinase production. Modes of action and the existence of possible elicitors of defense response in O. gratissimum leaf extracts are discussed.


2021 ◽  
Vol 9 (7) ◽  
pp. 1441
Author(s):  
Van Bach Lam ◽  
Thibault Meyer ◽  
Anthony Arguelles Arias ◽  
Marc Ongena ◽  
Feyisara Eyiwumi Oni ◽  
...  

Rice monoculture in acid sulfate soils (ASSs) is affected by a wide range of abiotic and biotic constraints, including rice blast caused by Pyricularia oryzae. To progress towards a more sustainable agriculture, our research aimed to screen the biocontrol potential of indigenous Bacillus spp. against blast disease by triggering induced systemic resistance (ISR) via root application and direct antagonism. Strains belonging to the B. altitudinis and B. velezensis group could protect rice against blast disease by ISR. UPLC–MS and marker gene replacement methods were used to detect cyclic lipopeptide (CLiP) production and construct CLiPs deficient mutants of B. velezensis, respectively. Here we show that the CLiPs fengycin and iturin are both needed to elicit ISR against rice blast in potting soil and ASS conditions. The CLiPs surfactin, iturin and fengycin completely suppressed P. oryzae spore germination resulting in disease severity reduction when co-applied on rice leaves. In vitro microscopic assays revealed that iturin and fengycin inhibited the mycelial growth of the fungus P. oryzae, while surfactin had no effect. The capacity of indigenous Bacillus spp. to reduce rice blast by direct and indirect antagonism in ASS conditions provides an opportunity to explore their usage for rice blast control in the field.


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