Control Of Bacterial Blight Research Articles

Copper formulations in bacterial blight control and toxic effects on coffee seedlings

Bacterial blight of coffee (Pseudomonas syringae pv. garcae) is an important coffee disease and can be controlled using antibiotics and copper-based compounds. However, copper-based compounds raise doubts among coffee growers regarding bacterial blight control efficiency and phytotoxic potential. In this work, coffee plants were sprayed with different copper molecules in order to study their efficiency on bacterial blight control and the phytotoxic potential. Seven copper formulations, cuprous oxide, copper oxychloride, copper nitrate, copper hydroxide 1 (water-dispersible granules) and 2 (concentrated suspension), copper sulfate 1 (complexed with gluconic acid) and 2 (Bordeaux mixture) were studied. The copper formulations efficiency was compared with the antibiotic kasugamycin, saline solution, and control. In controlled environmental conditions of temperature, relative humidity, and photoperiod, coffee seedlings were sprayed with the treatments and after 24 hours they were inoculated with Pseudomonas syringae pv. garcae suspension. Disease incidence and severity assessments were performed in a 2-day interval during a 16-day period. Phytotoxicity incidence and severity, mapping, and quantification of copper on the leaf tissue surface, dried leaves weight, and total copper leaf content were assessed 16 days after pathogen inoculation. Data were submitted to the Scott-Knott test (p < 0.05). Cuprous oxide and copper sulfate 2 proved most efficient to bacterial blight control, causing lower phytotoxicity effect, best covering, and persistence on leaf tissues. Copper nitrate and copper sulfate complexed with gluconic acid were more phytotoxicity compared to other copper formulations.

Integrated disease management practices for the control of bacterial blight in pomegranate in karnataka

Integrated disease management practices for the control of bacterial blight in pomegranate in karnataka

ВЫДЕЛЕНИЕ БАКТЕРИОФАГОВ PSEUDOMONAS SAVASTANOI PV. GLYCINEA И ИХ ИСПОЛЬЗОВАНИЕ В ЗАЩИТЕ СОИ ОТ БАКТЕРИАЛЬНОГО ОЖОГА

Bacterial blight is one of most harmful diseases of legumes, reducing the profitability of soybean production in Russian Federation. Among a number of Pseudomonas isolates obtained from diseased seeds and plants of soybean, 4 strains were selected and confirmed as Pseudomonas savastanoipv. glycinea (Psg). Properties of the isolated bacteria were similar to type strain of Psg CFBP 2214 in plant virulence, LOPAT tests, and PCR analysis for coronafacate ligase gene, and partly – in the phage reaction profile. Four isolates of bacteriophages specific to Psg were obtained from soil samples taken from fields with soybean crops. Virulence testing for the bacteriophages showed that bacteriophage ϕG17 infected 4 of 5 tested Psg strains, and it was chosen for further experiments with bacterial blight control. The bacteriophague effect control conducted on soybent plants inoculated by Psg experiments confirmed that 2 treatments of plants by the bacteriophage significantly reduced the disease development. Biological effect of the bacteriophage application was 74.75%, which is very close to the pesticide Strekar in a concentration of 0.5%.

First method for dissolving zinc thiazole and re-evaluation of its antibacterial properties against rice bacterial blight disease

Rice bacterial blight (BB), caused by Xanthomonas oryzae pv. oryzae (Xoo), is one of the most destructive diseases in rice-growing regions worldwide. Zinc thiazole is a novel bactericide and has been applied for BB control for 10 years. However, zinc thiazole is highly insoluble in water and in most organic solvents. In this work, we found for the first time that zinc thiazole can be dissolved in dimethyl sulfoxide (DMSO), and the solubility of zinc thiazole in DMSO is more than 20 mg/mL. Dissolved zinc thiazole at 25 μg/mL significantly inhibited the growth of Xoo by 58.81%. Interestingly, zinc thiazole at 25 μg/mL enhanced the cell division and altered the cell wall integrity of Xoo. The application of dissolved zinc thiazole at 100 μg/mL reduced the incidence of rice bacterial blight (BB) by providing 64.71% control efficacy, while zinc thiazole as suspension concentrate (SC) at 100 μg/mL only provided 43.42% control efficacy. Taken together, this study provides for the first time a method for dissolving zinc thiazole, and may help to better understand the antibacterial mechanism of zinc thiazole.

Kasugamycin influence on bacterial blight of coffee and on green coffee beans physicochemical quality

Brazil stands out as the world’s largest coffee exporter. However, in the cold and windy regions, such as the southern of Minas Gerais, have been undergoing attack of diseases, including the bacterial blight of coffee caused by the bacterium <em>Pseudomonas syringae</em> pv. <em>garcae</em>, which despite not having the same importance as the coffee leaf rust, is causing damages and losses to the coffee plantation. The control is mainly done through preventive measures such as installation of windbreaks. When bacterial blight of coffee is already installed, the chemical control is used with syrups of copper-based products and antibiotics. The aim of the present study was to verify the efficiency of the antibiotic kasugamycin associated with copper hydroxide in the control of bacterial blight of coffee and raw coffee beans quality. The experimental design was a randomized block with five treatments, four replicates and plots of 10 plants in the field where the treatments consisted of different concentrations of the kasugamycin: 0.0, 250, 500, 750 and 1000 mL ha<sup>-1</sup> added with 1.0 L copper hydroxide. The percent analysis was performed on the raw beans in order to verify their physical and chemical quality. The obtained results demonstrate that the solution is efficient in the control of bacterial blight of coffee as well as in the improvement of vegetative vigor and production, but does not influence the quality of raw coffee bean.

Ectopic activation of the rice NLR heteropair RGA4/RGA5 confers resistance to bacterial blight and bacterial leaf streak diseases.

Bacterial blight (BB) and bacterial leaf streak (BLS) are important diseases in Oryza sativa caused by Xanthomonas oryzae pv. oryzae (Xoo) and Xanthomonas oryzae pv. oryzicola (Xoc), respectively. In both bacteria, transcription activator-like (TAL) effectors are major virulence determinants that act by transactivating host genes downstream of effector-binding elements (EBEs) bound in a sequence-specific manner. Resistance to Xoo is mostly related to the action of TAL effectors, either by polymorphisms that prevent the induction of susceptibility (S) genes or by executor (R) genes with EBEs embedded in their promoter, and that induce cell death and resistance. For Xoc, no resistance sources are known in rice. Here, we investigated whether the recognition of effectors by nucleotide binding and leucine-rich repeat domain immune receptors (NLRs), the most widespread resistance mechanism in plants, is also able to stop BB and BLS. In one instance, transgenic rice lines harboring the AVR1-CO39 effector gene from the rice blast fungus Magnaporthe oryzae, under the control of an inducible promoter, were challenged with transgenic Xoo and Xoc strains carrying a TAL effector designed to transactivate the inducible promoter. This induced AVR1-CO39 expression and triggered BB and BLS resistance when the corresponding Pi-CO39 resistance locus was present. In a second example, the transactivation of an auto-active NLR by Xoo-delivered designer TAL effectors resulted in BB resistance, demonstrating that NLR-triggered immune responses efficiently control Xoo. This forms the foundation for future BB and BLS disease control strategies, whereupon endogenous TAL effectors will target synthetic promoter regions of Avr or NLR executor genes.

Marker-aided Incorporation of Xa38, a Novel Bacterial Blight Resistance Gene, in PB1121 and Comparison of its Resistance Spectrum with xa13 + Xa21.

Basmati rice is preferred internationally because of its appealing taste, mouth feel and aroma. Pusa Basmati 1121 (PB1121) is a widely grown variety known for its excellent grain and cooking quality in the international and domestic market. It contributes approximately USD 3 billion to India’s forex earning annually by being the most traded variety. However, PB1121 is highly susceptible to bacterial blight (BB) disease. A novel BB resistance gene Xa38 was incorporated in PB1121 from donor parent PR114-Xa38 using a modified marker-assisted backcross breeding (MABB) scheme. Phenotypic selection prior to background selection was instrumental in identifying the novel recombinants with maximum recovery of recurrent parent phenome. The strategy was effective in delimiting the linkage drag to <0.5 mb upstream and <1.9 mb downstream of Xa38 with recurrent parent genome recovery upto 96.9% in the developed NILs. The NILs of PB1121 carrying Xa38 were compared with PB1121 NILs carrying xa13 + Xa21 (developed earlier in our lab) for their resistance to BB. Both NILs showed resistance against the Xoo races 1, 2, 3 and 6. Additionally, Xa38 also resisted Xoo race 5 to which xa13 + Xa21 was susceptible. The PB1121 NILs carrying Xa38 gene will provide effective control of BB in the Basmati growing region.

Biological control of Xanthomonas Oryzae pv. Oryzae causing rice bacterial blight disease by Streptomyces toxytricini VN08-A-12, isolated from soil and leaf-litter samples in Vietnam.

A total of 2690 actinomycete strains were screened as potential biological control agents in controlling rice bacterial blight (BB) in Vietnam. From these microorganisms, seventeen actinomycete strains were found to be capable of inhibiting all 10 major Xoo races isolated from Xoo-infected rice leaves. One strain, namely VN08-A-12, contained effective characteristics in selectively inhibiting all 10 races in vitro, but did not inhibit most of the other tested microorganisms. Therefore, VN08-A-12 was subsequently selected for rice field trials for two seasons on two rice cultivars SS1 and KD18. Results showed VN08-A-12 was not only able to reduce Xoo lesion lengths in the two rice cultivars (lesion length reduction of up to 38.3%), but it also significantly reduced Xoo-related yield loss in infected rice cultivars from the field (yield loss reduction of up to 43.2%). Interestingly, the culture of this strain also increased the rice yield in healthy rice cultivars (from 2.66% to 16.98% for SS1 and from 3.11% to 5.94% for KD18 cultivar). The strain VN08-A-12 was shown to be identical to Streptomyces toxytricini. To our knowledge, this is the first study reporting S. toxytricini as a beneficial biological agent for the control of BB in rice.

Fungicidas cúpricos, cloretos de benzalcônio e composto bioativo liquído (Bokashi): fitotoxicidade e controle da seca dos ponteiros causada por Erwinia psidii em goiabeiras

Diferentes formulacoes de fungicidas cupricos, cloretos de benzalconio e de composto bioativo liquido foram testados para o controle da seca dos ponteiros causada por Erwinia psidii em goiabeira (Psidium guajava), observando-se os possiveis efeitos fitotoxicos. O experimento foi conduzido em pomar comercial de goiabeira das variedades Pedro Sato e Comum, no municipio de Brazlândia, DF. Os tratamentos constaram dos seguintes produtos/L de agua: 5,0 g de sulfato de cobre (SC), 3,5 g de oxicloreto de cobre (OC), 3,0 g de hidroxido de cobre (HC), 3,0 mL de cloretos de benzalconio (CB) e 20,0 mL de composto bioativo liquido (CBL). A fitotoxicidade foi avaliada em botoes florais e frutos, em tres estadios de desenvolvimento, e a incidencia da doenca, em 10 ramos de frutificacao em cada quadrante da planta nos mesmos estadios. Na variedade Pedro Sato, em frutos de tamanho inferior a 15 mm nao foram observados sintomas severos de fitotoxicidade, no entanto, na variedade Comum foi possivel observar sintomas severos ocasionados pelos cupricos; em frutos entre 16 e 30 mm e acima de 31 mm, em ambas as variedades, foram observados sintomas moderados a severos, ocasionados principalmente pelo SC. No controle da doenca, os tratamentos com SC, OC, HC e CBL foram mais eficientes na variedade Pedro Sato, enquanto o CBL foi mais eficiente na variedade Comum. Em ambas as variedades o CBL mostrou menor Area Abaixo da Curva de Progresso da Doenca (AACPD).

Evaluation of seed treatment chemicals for the control of seedling bacterial blight in cowpea in northern Nigeria

The effect of metalaxyl + mancozeb (RidomilMz), metalaxyl + carboxin + furathiocarb (Apron plus), metalaxyl + copper-1-oxide (Ridomil plus), benomyl (Benlate), maneb + thiophanate-methyl (Labilite) and zinc + maneb (Mycotrin) on seed germination, incidence and severity of seedling bacterial blight in cowpea induced by Xanthomonas campestris pv vignicola was assessed on the field in the 2000 and 2001 cropping seasons. Zinc + maneb gave the best control and was closely followed by metalaxyl + carboxin + furathiocarb. Others were moderate in their effects except benomyl that was slightly better than the check. The need for appropriate use of seed treatment chemical for the control of bacterial blight is discussed.

Biological Control of Bacterial Blight of Geranium with H-Mutant Bacteriophages

Bacterial blight, caused by Xanthomonas campestris pv. pelargonii (XCP), is considered the most serious disease of geraniums (Pelargonium × hortorum). A novel approach that uses bacteriophages (phages, viruses that kill bacteria) for the biological control of geranium blight will be presented. Phages were once abandoned as biological control agents due to the emergence of bacterial mutants resistant to the phages employed. However, our approach utilizes a mixture of three to eight different phages including host-range mutants (H-mutants). H-mutants are spontaneously derived from their wild-type parent phages and lyse not only parent wild-type bacteria, but also phage-resistant mutants originating from parent bacteria. Two phages specific for XCP initially were isolated from soil samples from Florida and California. These phages produced virulent reactions in six of 30 XCP strains, and lysogenic reactions in 22 strains. After selection of these phages for increased virulence and additional phages were isolated from MN and UT, 17 phages were evaluated for sensitivity to 21 XCP strains from around the world. Four to 14 phages produced virulent reactions in the 21 XCP strains. Five phages produced virulent reactions in at least 17 XCP strains. A mixture of five phages tested against the 21 XCP strains produced virulent reactions for all 21 XCP strains. Geraniums in 10-cm pots were inoculated with XCP and placed on a greenhouse bench in the middle of 5 non-inoculated plants. After 2 weeks of daily spraying plants with a phage solution (109 pfu phage/ml) or water, there was a 71% reduction in the number of bacterial lesions on phage-treated plants.

Control of bacterial blight of cowpea(Vigna unquiculata(l.) walp.)

Abstract Five chemicals namely, Agrimycin‐100 (600 μg/ml), Streptocycline (100 μg/ml), Bavistin (500 μg/ml), Blitox‐50 W.P. (2000 μg/ml), Dithane M‐45 (2000 μg/ml) and nine combinations of the last four chemicals were evaluated as foliar sprays during Monsoon 1982 for the control of bacterial blight of cowpea. All the treatments significantly controlled the disease but the two most effective treatments were: (i) three sprays of Streptocycline (100 μg/ml) + Bavistin (500 μg/ml) and (ii) two sprays of Streptocycline (100 μg/ml) + Bavistin (500 μg/ml) followed by third spray of Streptocycline (100 μg/ml) + Blitox‐50 W.P. (2000 μg/ml). Four seed treatments, namely hot water (50 °C for 30 min), solar heat, Streptocycline (100 μg/ml) + Agallol (2000 μg/ml) and Streptocycline (100 μg/ml) + Captan (2000 μg/ml), the two most effective spraying schedules mentioned above and eight combinations of seed treatments and spraying schedules were evaluated during Monsoon 1983 and 1984. All the seed treatments significantly...

Screening Antibiotics for Their Control of Bacterial Blight (BB)

Screening Antibiotics for Their Control of Bacterial Blight (BB)

Epidemiology and Control of Bacterial Blight and Canker of Cowpea

Epidemiology and Control of Bacterial Blight and Canker of Cowpea

Bacterial Blight of Cotton

Summary1. Bacterial blight of cotton is potentially one of the most damaging diseases of cotton.2. Its symptoms and adverse effect on yield are described.3. Control measures include: (i) cultural techniques of crop sanitation, and the destruction of crop residues, as well as close seasons and crop rotation; (ii) chemical seed treatments and foliar sprays; (iii) the breeding of resistant varieties.4. Techniques are described for the breeding of resistant varieties, and sources of useful genetic plant resistance identified.5. The complex nature of the interactions between host genetic resistance, variation in the pathogen and environment is emphasized.6. Successful resistance‐breeding programmes in Africa and the USA are reviewed, and attention is drawn to the pressing need for resistant varieties in India and Pakistan.7. Continued success in the control of bacterial blight will require integrated programmes that include cultural methods, the use of chemicals (particularly as seed treatments) and the cultivation of resistant varieties with durable resistance.

The control of bacterial blight in rain-grown cotton. II. Some effects of infection on growth and yield

Three series of experiments are described from which minimum estimates of crop loss caused by bacterial blight were obtained. In the first two, the estimates were derived from seed-dressing trials, and in the third, seed dressing was used in conjunction with resistant varieties.Losses amounted to as much as 354 ± 39 lb. seed cotton/acre for a susceptible variety but could be reduced both by seed dressing and by using resistant varieties. The effectiveness of resistance in moderately resistant varieties varied from one season to the next, an effect comparable with the genotype-environment interactions previously described for reactions to inoculation.

The control of bacterial blight in rain-grown cotton I. Breeding for resistance in African Upland varieties

Projects carried out in the Lake Province of Tanganyika for breeding Upland cotton resistant to bacterial blight are described.A programme in which Albar 51 was used as resistant parent was more successful than one in which an attempt was made to transfer the major gene B6m to breeding stocks.Backcrossing was found to be of limited value as a breeding technique with rain-grown cotton, line breeding in segregating stocks being preferred.It is demonstrated that resistant types can be synthesized by the systematic exploitation of residual genetic variability in locally adapted populations.Correlations between stem, boll andleaf resistance are discussed and some deviations attributable to environmental effects described. It is inferred that there is a basic resistance mechanism in all tissues which is under the same genetic control but that results may be confused by genotype-environment interactions and by other factors operating in particular tissues.The approach to resistance breeding is discussed in relation to the evolution of resistance in African Upland cotton. It is concluded that improvement by straight selection should be given equal emphasis with improvement by hybridization in resistance breeding programmes.