scholarly journals Relationship between Nitrogen Fertilization and Bacterial Canker in `French' Prune

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 520C-520 ◽  
Author(s):  
S.M. Southwick ◽  
M.E. Rupert ◽  
J.T. Yeager ◽  
K.G. Weis ◽  
B.C. Kirkpatrick ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Disease Incidence ◽  
Bacterial Canker ◽  
Growth Responses ◽  
N Application ◽  
Compacted Soils ◽  
Significant Relationships ◽  
Vigorous Growth ◽  
Serious Disease ◽  
N Use

Bacterial canker (BC), caused by Pseudomonas syringae pv. syringae van Hall, is a serious disease of stone fruits that occurs most commonly in young orchards. Many factors can predispose or increase the risk that trees develop BC such as sandy or compacted soils, low soil pH, inadequate tree nutrition, frost or cold injury, genetic susceptibility, and presence of ring nematode, Criconemella spp. However, questions still remain about how these factors influence disease incidence in `French' prune, Prunus domestica L. In 1991, we established a 3.64-ha plot in Winters, Calif., to determine the effects of nitrogen (N) fertigation on growth responses and yield of young prune trees. N was applied through a surface drip system at 0, 0.11, 0.23, and 0.45 kg actual N/tree per year as UN32 urea (Unocal, Sacramento Calif.) with 1/10th of the total amount delivered per application every other week from May through September starting in 1992. Two other treatments were also included: 0.064 kg N/tree per year through surface drip if % leaf N dropped below 2.3%, and 0.23 kg N/tree/year delivered in small amounts every irrigation via an automated buried drip system. Symptoms of BC began appearing primarily in the 0- and 0.064-N treatments in 1993. During 1995 and 1996, we demonstrated highly significant relationships between low N status measured in leaves and increased incidence of BC. Furthermore, we determined levels of N application via drip irrigation, which resulted in good yields, vigorous growth, and lack of BC in our test plots, but also minimized N use and potential for nitrate leaching into groundwater. These and additional results will be presented.

scholarly journals In vitro inhibition of Pseudomonas syringae pv actinidiae by wound protectants

2015 ◽  
Vol 68 ◽  
pp. 332-339
Author(s):  
D.A. Cornish ◽  
J. Yu ◽  
J.M. Oldham ◽  
J. Benge ◽  
W. Max ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Antibacterial Activity ◽  
Pseudomonas Syringae ◽  
Disease Incidence ◽  
Bacterial Canker ◽  
Streptomycin Sulphate ◽  
Chain Reaction ◽  
Commercial Formulation ◽  
Polymerase Chain

Preventing Pseudomonas syringae pv actinidiae (Psa) the causal agent of bacterial canker of kiwifruit from entering pruning wounds would reduce disease incidence and facilitate canopy management Antibacterial activity against Psa has been determined in the laboratory for active ingredients commercially available in New Zealand Only tebuconazole tebuconazole with octhilinone and a formulation of cyproconazole and iodocarb killed Psa on agar plates or in liquid medium However only tebuconazole with octhilinone killed Psa within 5 min Psa was detected by polymerase chain reaction following plating on instruments used for applying wound protectants in an infected orchard This suggests that under some conditions the pathogen could be transferred from vine to vine when applying some wound protectants Addition of streptomycin sulphate to tebuconazole or a formulation of cyproconazole and iodocarb did not result in a rapid and complete kill of Psa similar to that with a commercial formulation of streptomycin applied alone

scholarly journals Kiwifruit under plastic covering: impact on fruit quality and on orchard microclimate

2018 ◽  
Vol 1 (1) ◽  
pp. 1 ◽  
Author(s):  
V. Chiabrando ◽  
G. Giacalone
Keyword(s):  
Pseudomonas Syringae ◽  
Fruit Quality ◽  
Cultural Practices ◽  
Disease Incidence ◽  
Disease Spread ◽  
Economic Losses ◽  
Bacterial Canker ◽  
Negative Consequences ◽  
The Impact

Italy has a preeminent rank in kiwifruit industry, being the first exporter and the second largest producer after China. However, in the last few years kiwifruit yields and the total cultivated area considerably decreased, due to the disease spread of the bacterial canker caused by Pseudomonas syringae pv. actinidiae (Psa). Bacterial canker has affected significantly orchards productivity and consequently has caused severe economic losses in all major areas of kiwifruit cultivation, including Italy,and considerable damage to the international kiwifruit industry.Several climatic conditions and cultural practices affect the development of the bacterial canker.Orchard hygiene, restrictions on the movement of nursery plants, orchard management and cultural practices, chemical and biological controls and breeding programs are being employed to limit the diffusion of the disease and help kiwifruit orchards to survive and produce. A possible way seems to be the modification of environmental conditions and it is being explored through the building of plastic covers over the orchards. This research work is focused on the impact of plastic cover on fruit quality, microclimate conditions and incidence of Psa. To evaluate the impact of plastic cover on microclimate, quality of fruits and disease incidence the following parameters were evaluated: climatic parameters (temperature, PAR), quality parameters (color, fruit firmness, titratable acidity, °Brix, vitamin C), disease incidence (%).  The use of a permanenttunnel modify light intensity and microclimate without any negative consequences on kiwifruits quality. Covering a kiwifruit orchard with a protective canopy reduces the spread of Psa throughout the orchard when covers are constructed over vines with low levels of infection.The use of plastic covers ensure the production of the current and future kiwifruit without compromising the quality of the fruit, but future trials will provide further information clarifying the effectiveness of the actual crop covers.

Effect of a protectant copper application on Psa infection of kiwifruit trap plants

2017 ◽  
Vol 70 ◽  
pp. 310-314
Author(s):  
J.L. Tyson ◽  
S.J. Dobson ◽  
M.A. Manning
Keyword(s):  
New Zealand ◽  
Disease Control ◽  
Pseudomonas Syringae ◽  
Low Risk ◽  
Bacterial Canker ◽  
Complete Protection ◽  
Leaf Spots ◽  
Copper Compounds ◽  
Trap Plants

Pseudomonas syringae pv. actinidiae (Psa) causes bacterial canker of kiwifruit, which is an ongoing threat to New Zealand kiwifruit production. Disease control depends on orchard practices such as removal of visibly diseased material, pruning during low-risk periods, and the application of foliar bactericides. Although the use of copper compounds on Actinidia species (kiwifruit) can cause phytotoxicity, copper-based formulations remain a key component of Psa control in New Zealand. The effect of single copper applications on Psa infection of ‘Hort16A’ trap plants was studied over the Spring of 2014 (Sept—Nov). Psa leaf spots were observed at the beginning of October, appearing first on the untreated plants. Although the copper sprays did not achieve complete protection, particularly as the inoculum built up during November, the copper-sprayed plants always had less disease than the untreated plants.

BIOASSAY TO DETERMINE CHERRY ROOTSTOCK TOLERANCE TO `BACTERIAL CANKER' CAUSED BY PSEUDOMONAS SYRINGAE PV SYRINGAE

HortScience ◽  
1990 ◽  
Vol 25 (11) ◽  
pp. 1354F-1355
Author(s):  
Elzbieta Krzesinska ◽  
Anita Nina Miller
Keyword(s):  
Relative Humidity ◽  
Pseudomonas Syringae ◽  
Bacterial Suspension ◽  
Avirulent Strain ◽  
Bacterial Canker ◽  
Symptom Development ◽  
Virulent Strains ◽  
Callus Production ◽  
Root Stock ◽  
One Year

An excised twig assay was developed to evaluate cherry geno-types for their tolerance to Pseudomonas syringae pv. syringae. One-year-old wood was collected at monthly intervals from October until January of `Royal Ann', `Corum', and a number of cherry rootstock. The rootstock included; F/12–1 and Giessen (GI) and M × M selections. A 2-cm incision (“^”-shaped flap) was made on each twig. A 20-μl droplet of inoculum or water was placed onto each incision. The inoculum was prepared with one avirulent (K4) and three virulent strains (W4N54, AP2, B15) concentrations (105, 106, or 107 cfu). Inoculated twigs were placed in test tubes and incubated at 15C in high relative humidity for 3 weeks. After incubation, twigs were evaluated for gummosis production (0–3, 0 = no gummosis), incision browning (1–4, 1 = yellow pith), and callus production (0–1, 0 = no callus). The concentration of bacterial suspension had no effect on symptom development. No gummosis or browning was observed on twigs inoculated with water or the avirulent strain. Based on the gummosis and browning ratings, rootstock M × M 2, M × M 39, M × M 60, GI 148-1, GI 154-2, and GI 154-4 were found to be resistant to these three strains of P. syringae in this assay. Root-stock F 12-1, GI 169–15, GI 172–9, and GI 173-9 were found to be tolerant.

scholarly journals A Synergic Potential of Antimicrobial Peptides against Pseudomonas syringae pv. actinidiae

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1461
Author(s):  
Nuno Mariz-Ponte ◽  
Laura Regalado ◽  
Emil Gimranov ◽  
Natália Tassi ◽  
Luísa Moura ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Antimicrobial Peptides ◽  
Pseudomonas Syringae ◽  
Pathogenic Bacteria ◽  
High Efficiency ◽  
Bacterial Canker ◽  
Membrane Permeation ◽  
Flow Cytometry Analysis ◽  
Pathogenic Agent ◽  
Peptide Mixtures

Pseudomonas syringae pv. actinidiae (Psa) is the pathogenic agent responsible for the bacterial canker of kiwifruit (BCK) leading to major losses in kiwifruit productions. No effective treatments and measures have yet been found to control this disease. Despite antimicrobial peptides (AMPs) having been successfully used for the control of several pathogenic bacteria, few studies have focused on the use of AMPs against Psa. In this study, the potential of six AMPs (BP100, RW-BP100, CA-M, 3.1, D4E1, and Dhvar-5) to control Psa was investigated. The minimal inhibitory and bactericidal concentrations (MIC and MBC) were determined and membrane damaging capacity was evaluated by flow cytometry analysis. Among the tested AMPs, the higher inhibitory and bactericidal capacity was observed for BP100 and CA-M with MIC of 3.4 and 3.4–6.2 µM, respectively and MBC 3.4–10 µM for both. Flow cytometry assays suggested a faster membrane permeation for peptide 3.1, in comparison with the other AMPs studied. Peptide mixtures were also tested, disclosing the high efficiency of BP100:3.1 at low concentration to reduce Psa viability. These results highlight the potential interest of AMP mixtures against Psa, and 3.1 as an antimicrobial molecule that can improve other treatments in synergic action.

scholarly journals Native Amazonian Canga Grasses Show Distinct Nitrogen Growth Responses in Iron Mining Substrates

Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 849
Author(s):  
Cecilio F. Caldeira ◽  
Madson O. Lima ◽  
Silvio J. Ramos ◽  
Markus Gastauer
Keyword(s):  
Native Species ◽  
Perennial Grasses ◽  
Growth Responses ◽  
Adaptive Traits ◽  
N Application ◽  
Gas Exchanges ◽  
Stomatal Morphology ◽  
Iron Mining ◽  
Adverse Environmental Conditions ◽  
Biomass Increase

Native species may have adaptive traits that are advantageous for overcoming the adverse environmental conditions faced during the early stages of mine land rehabilitation. Here, we examined the nitrogen (N) growth responses of two native perennial grasses (Axonopus longispicus and Paspalum cinerascens) from canga in nutrient-poor iron mining substrates. We carried out vegetative propagation and recovered substantial healthy tillers from field-collected tussocks of both species. These tillers were cultivated in mining substrates at increasing N levels. The tillering rates of both species increased with the N application. Nonetheless, only in P. cinerascens did the N application result in significant biomass increase. Such growth gain was a result of changes in leaf pigment, stomatal morphology, gas exchanges, and nutrients absorption that occurred mainly under the low N additions. Reaching optimum growth at 80 mg N dm−3, these plants showed no differences from those in the field. Our study demonstrates that an input of N as fertilizer can differentially improve the growth of native grasses and that P. cinerascens plants are able to deposit high quantities of carbon and protect soil over the seasons, thus, making them promising candidates for restoring nutrient cycling, accelerating the return of other species and ecosystem services.

scholarly journals Bacterial Leaf Spot of Celery in California: Etiology, Epidemiology, and Role of Contaminated Seed

Plant Disease ◽  
1997 ◽  
Vol 81 (8) ◽  
pp. 892-896 ◽  
Author(s):  
E. L. Little ◽  
S. T. Koike ◽  
R. L. Gilbertson
Keyword(s):  
Pseudomonas Syringae ◽  
Leaf Spot ◽  
Disease Incidence ◽  
Field Tests ◽  
Hot Water ◽  
Disease Development ◽  
Bacterial Leaf Spot ◽  
Overhead Irrigation ◽  
Celery Seed ◽  
Salinas Valley

Pseudomonas syringae pv. apii, causal agent of bacterial leaf spot (BLS) of celery, was first identified in California in 1989. By 1991, BLS was apparent in all celery-growing areas of the state. Greenhouse-produced transplants were affected most severely, and disease incidence approached 100% in some greenhouses. In this study, sources of inoculum and factors contributing to disease development were investigated in three Salinas Valley greenhouse operations during the 1991, 1992, and 1993 celery transplant seasons (January to August). Epiphytic P. syringae pv. apii was not detected on celery transplants until April or May of each year. Increased epiphytic populations preceded BLS outbreaks, and high-pressure, overhead irrigation favored bacterial infiltration and disease development. In seed-wash assays, P. syringae pv. apii was recovered from 5 of 24 commercial celery seed lots. In field tests, epiphytic P. syringae pv. apii was found on umbels of inoculated celery plants, and seeds from these plants were heavily contaminated with P. syringae pv. apii. Contaminated seed produced seedlings with large epiphytic P. syringae pv. apii populations. Hot-water treatment (50°C for 25 min) eliminated >99.9% of seed contamination. Based on these results, disease management techniques are proposed.

INFLUENCE OF THE SYSTEM OF RICE INTENSIFICATION ON RICE YIELD AND NITROGEN AND WATER USE EFFICIENCY WITH DIFFERENT N APPLICATION RATES

2009 ◽  
Vol 45 (3) ◽  
pp. 275-286 ◽  
Author(s):  
LIMEI ZHAO ◽  
LIANGHUAN WU ◽  
YONGSHAN LI ◽  
XINGHUA LU ◽  
DEFENG ZHU ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
N Use Efficiency ◽  
System Of Rice Intensification ◽  
N Application ◽  
Application Rates ◽  
Rice Intensification ◽  
Use Efficiency ◽  
N Rates ◽  
N Use

SUMMARYField experiments were conducted in 2005 and 2006 to investigate the impacts of alternative rice cultivation systems on grain yield, water productivity, N uptake and N use efficiency (ANUE, agronomic N use efficiency; PFP, partial factor productivity of applied N). The trials compared the practices used with the system of rice intensification (SRI) and traditional flooding (TF). The effects of different N application rates (0, 80, 160 and 240 kg ha−1) and of N rates interacting with the cultivation system were also evaluated. Resulting grain yields with SRI ranged from 5.6 to 7.3 t ha−1, and from 4.1 to 6.4 t ha−1 under TF management. On average, grain yields under SRI were 21% higher in 2005 and 22% higher in 2006 than with TF. Compared with TF, SRI plots had higher harvest index across four fertilizer N rates in both years. However, there was no significance difference in above-ground biomass between two cultivation systems in either year. ANUE was increased significantly under SRI at 80 kg N ha−1 compared with TF, while at higher N application rates, ANUE with SRI was significantly lower than TF. Compared with TF, PFP under SRI was higher across all four N rates in both years, although the difference at 240 kg N ha−1 was not significant. As N rate increased, the ANUE and PFP under both SRI and TF significantly decreased. Reduction in irrigation water use with SRI was 40% in 2005 and 47% in 2006, and water use efficiency, both total and from irrigation, were significantly increased compared to TF. With both SRI and TF, the highest N application was associated with decreases in grain yield, N use efficiency and water use efficiency. This is an important finding given current debates whether N application rates in China are above the optimum, especially considering consequences for soil and water resources. Cultivation system, N rates and their interactions all produced significant differences in this study. Results confirmed that optimizing fertilizer N application rates under SRI is important to increase yield, N use efficiency and water use efficiency.

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