Abstract
Recent field observations by growers suggest that increased nitrogen (N) content in nursery trees resulting from foliar sprays with urea in the autumn increases tree susceptibility to infection by Phytophthora syringae . We investigated the effects of soil N availability and spraying pear ( Pyrus communis ‘OHF 97’) trees with combinations of urea, chelated copper ethylenediaminetetraacetic acid (CuEDTA), and phosphonate-containing fungicides on stem N concentration and susceptibility to infection by P. syringae . Increasing soil N availability increased susceptibility to P. syringae and increased N and amino acid concentration in stems. Spraying trees with urea in the autumn increased concentrations of N and amino acids in stems and had no significant effect on tree susceptibility when stems were inoculated with P. syringae before or after urea sprays. Spraying trees with CuEDTA decreased stem N concentrations and had no significant influence on tree susceptibility to P. syringae when stems were inoculated before or after CuEDTA sprays. These results suggest the relationship between tree susceptibility to P. syringae and tree N concentration may be specific to the form of N, delivery method, or timing of N applications. Trees had higher N concentrations in stems in November than in October and were more susceptible to P. syringae when inoculated in November, suggesting that environmental factors and increasing tree dormancy may be responsible for changes in susceptibility to the pathogen. Spraying trees with fungicides containing fosetyl-aluminum in October or November decreased tree susceptibility to P. syringae . The effects of fungicides containing fosetyl-aluminum on susceptibility were similar regardless of whether trees were sprayed or not with urea or CuEDTA, suggesting that these fungicides can be used in combination with urea or CuEDTA sprays for reducing disease severity caused by P. syringae without impacting growers' objective of increasing tree N content with urea or enhancing early defoliation with CuEDTA.
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Claims 11
Claim · model-written summary
More soil nitrogen increased pear susceptibility to P. syringae.
- Taxon
- pear
_Poirier_Fleurs_et_feuilles.jpg?width=60)
Pyrus communise1 - Treatment
- Increasing soil N availabilitye0
- Interactor
- P. syringaePhytophthora syringaee0pathogen
- Outcome
- susceptibility to P. syringaee0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_Poirier_Fleurs_et_feuilles.jpg?width=500)
Verbatim
e0“Increasing soil N availability increased susceptibility to P. syringae and increased N and amino acid concentration in stems”
e1“spraying pear ( Pyrus communis ‘OHF 97’) trees”
Claim · model-written summary
More soil nitrogen increased stem N and amino acid concentration.
- Taxon
- pearPyrus communise1
- Treatment
- Increasing soil N availabilitye0
- Outcome
- N and amino acid concentration in stemse0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increasing soil N availability increased susceptibility to P. syringae and increased N and amino acid concentration in stems”
e1“spraying pear ( Pyrus communis ‘OHF 97’) trees”
Claim · model-written summary
Autumn urea sprays increased stem N and amino acids.
- Taxon
- pearPyrus communise1
- Treatment
- Spraying trees with urea in the autumne0
- Outcome
- concentrations of N and amino acids in stemse0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Spraying trees with urea in the autumn increased concentrations of N and amino acids in stems”
e1“spraying pear ( Pyrus communis ‘OHF 97’) trees”
Claim · model-written summary
Autumn urea sprays did not significantly affect susceptibility to P. syringae before or after inoculation.
- Taxon
- pearPyrus communise1
- Treatment
- urea sprayse0
- Interactor
- P. syringaePhytophthora syringaee0pathogen
- Outcome
- tree susceptibilitye0
- Direction
- no significant effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“had no significant effect on tree susceptibility when stems were inoculated with P. syringae before or after urea sprays”
e1“spraying pear ( Pyrus communis ‘OHF 97’) trees”
Claim · model-written summary
CuEDTA sprays decreased stem N concentrations.
- Taxon
- pearPyrus communise1
- Treatment
- CuEDTAe0
- Outcome
- stem N concentrationse0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Spraying trees with CuEDTA decreased stem N concentrations”
e1“spraying pear ( Pyrus communis ‘OHF 97’) trees”
Claim · model-written summary
CuEDTA sprays did not significantly influence susceptibility to P. syringae.
- Taxon
- pearPyrus communise1
- Treatment
- CuEDTA sprayse0
- Interactor
- P. syringaePhytophthora syringaee0pathogen
- Outcome
- tree susceptibility to P. syringaee0
- Direction
- no significant influencee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“had no significant influence on tree susceptibility to P. syringae when stems were inoculated before or after CuEDTA sprays”
e1“spraying pear ( Pyrus communis ‘OHF 97’) trees”
Claim · model-written summary
Pear stems had higher N concentrations in November than October.
- Taxon
- pearPyrus communise1
- Outcome
- N concentrations in stemse0
- Direction
- highere0
- Comparator
- Octobere0
- Setting
- Novembere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Trees had higher N concentrations in stems in November than in October”
e1“spraying pear ( Pyrus communis ‘OHF 97’) trees”
Claim · model-written summary
Pear trees were more susceptible to P. syringae when inoculated in November.
- Taxon
- pearPyrus communise1
- Interactor
- P. syringaePhytophthora syringaee0pathogen
- Outcome
- susceptible to P. syringaee0
- Direction
- moree0
- Setting
- Novembere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“were more susceptible to P. syringae when inoculated in November”
e1“spraying pear ( Pyrus communis ‘OHF 97’) trees”
Claim · model-written summary
Fosetyl-aluminum fungicides decreased pear susceptibility to P. syringae.
- Taxon
- pearPyrus communise1
- Treatment
- fungicides containing fosetyl-aluminume0
- Interactor
- P. syringaePhytophthora syringaee0pathogen
- Outcome
- tree susceptibility to P. syringaee0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Spraying trees with fungicides containing fosetyl-aluminum in October or November decreased tree susceptibility to P. syringae”
e1“spraying pear ( Pyrus communis ‘OHF 97’) trees”
Claim · model-written summary
Fosetyl-aluminum fungicide efficacy was similar with or without urea or CuEDTA sprays.
- Taxon
- pearPyrus communise1
- Treatment
- fungicides containing fosetyl-aluminume0
- Outcome
- susceptibilitye0
- Direction
- similare0
- Comparator
- sprayed or not with urea or CuEDTAe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The effects of fungicides containing fosetyl-aluminum on susceptibility were similar regardless of whether trees were sprayed or not with urea or CuEDTA”
e1“spraying pear ( Pyrus communis ‘OHF 97’) trees”
Claim · model-written summary
The authors suggest combining fosetyl-aluminum fungicides with urea or CuEDTA sprays for disease reduction.
- Taxon
- pearPyrus communise1
- Treatment
- fungicidese0
- Interactor
- P. syringaePhytophthora syringaee0pathogen
- Outcome
- reducing disease severity caused by P. syringaee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“these fungicides can be used in combination with urea or CuEDTA sprays for reducing disease severity caused by P. syringae”
e1“spraying pear ( Pyrus communis ‘OHF 97’) trees”
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See all 12 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.