Abstract
Liberibacter asiaticus' (CLas) is the causal agent of citrus HLB in Florida. Bactericides containing the active ingredient oxytetracycline (OTC) have been used in foliar spray to control citrus HLB in Florida since 2016. However, the minimum concentration of OTC required to suppress CLas in planta remains unknown. We developed a new method for evaluating the effects of OTC treatment on CLas titers in infected plants and determined the relationship between OTC residue levels and control levels achieved for CLas using mathematical modeling in greenhouse and field experiments. In both greenhouse and field, OTC spray did not reduce the titers of CLas, and it produced undetectable or mild levels of OTC residue in leaves within 7 days post-application (DPA). In greenhouse, OTC injection at 0.05 g per tree decreased CLas titers to an undetectable level (cycle threshold value ≥ 36.0) from 7 to 30 DPA and produced a residue level of OTC at 0.68 to 0.73 µg/g of fresh tissue over this period. In the field, OTC injection at 0.50 g per tree resulted in the decline of CLas titers by 1.52 log reduction from 14 to 60 DPA, with residue levels of OTC at 0.27 to 0.33 µg/g of fresh tissue. In both trials, a first-order compart model of OTC residue dynamics in leaves of trunk-injected trees was specified for estimating the retention of effective concentrations. Furthermore, nonlinear modeling revealed significant positive correlations between OTC residue levels in leaves and the control levels for CLas achieved. The results suggested that the minimum concentrations of OTC required to suppress CLas populations in planta to below the detection limit are 0.68 and 0.86 µg/g and that the minimum concentrations of OTC required for initial inhibition of CLas growth in planta are ∼0.17 and ∼0.215 µg/g in leaf tissues under greenhouse and field conditions, respectively. This finding highlights that a minimum concentration of OTC should be guaranteed to be delivered to target CLas in infected plants for effective control of citrus HLB.
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Claims 10
Claim · model-written summary
OTC spray did not reduce CLas titers in citrus in greenhouse or field trials.
- Treatment
- OTC spraye1
- Interactor
- CLase0pathogen
- Outcome
- titers of CLase1
- Direction
- did not reducee1
- Setting
- greenhouse and fielde1
CitrusNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Liberibacter asiaticus' (CLas) is the causal agent of citrus HLB in Florida”
e1“In both greenhouse and field, OTC spray did not reduce the titers of CLas”
Claim · model-written summary
OTC spray produced undetectable or mild OTC residue levels in leaves within 7 days post-application.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Liberibacter asiaticus' (CLas) is the causal agent of citrus HLB in Florida”
e2“it produced undetectable or mild levels of OTC residue in leaves within 7 days post-application (DPA)”
Claim · model-written summary
In greenhouse, OTC injection at 0.05 g per tree decreased CLas titers to an undetectable level from 7 to 30 DPA.
- Treatment
- OTC injection at 0.05 g per treee3
- Interactor
- CLase0pathogen
- Outcome
- CLas titerse3
- Direction
- decreasede3
- Value
- undetectable level (cycle threshold value ≥ 36.0)e3
- Qualifier
- from 7 to 30 DPAe3
- Setting
- In greenhousee3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Liberibacter asiaticus' (CLas) is the causal agent of citrus HLB in Florida”
e3“In greenhouse, OTC injection at 0.05 g per tree decreased CLas titers to an undetectable level (cycle threshold value ≥ 36.0) from 7 to 30 DPA and produced a residue level of OTC at 0.68 to 0.73 µg/g of fresh tissue over this period”
Claim · model-written summary
In greenhouse, OTC injection at 0.05 g per tree produced an OTC residue of 0.68 to 0.73 µg/g of fresh tissue.
- Treatment
- OTC injection at 0.05 g per treee3
- Outcome
- residue level of OTCe3
- Value
- 0.68 to 0.73 µg/g of fresh tissuee3
- Setting
- greenhousee3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Liberibacter asiaticus' (CLas) is the causal agent of citrus HLB in Florida”
e3“In greenhouse, OTC injection at 0.05 g per tree decreased CLas titers to an undetectable level (cycle threshold value ≥ 36.0) from 7 to 30 DPA and produced a residue level of OTC at 0.68 to 0.73 µg/g of fresh tissue over this period”
Claim · model-written summary
In the field, OTC injection at 0.50 g per tree caused a 1.52 log reduction in CLas titers from 14 to 60 DPA.
- Treatment
- OTC injection at 0.50 g per treee4
- Interactor
- CLase0pathogen
- Outcome
- CLas titerse4
- Direction
- declinee4
- Value
- 1.52 log reductione4
- Qualifier
- from 14 to 60 DPAe4
- Setting
- In the fielde4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Liberibacter asiaticus' (CLas) is the causal agent of citrus HLB in Florida”
e4“In the field, OTC injection at 0.50 g per tree resulted in the decline of CLas titers by 1.52 log reduction from 14 to 60 DPA, with residue levels of OTC at 0.27 to 0.33 µg/g of fresh tissue”
Claim · model-written summary
In the field, OTC residue levels in leaves were 0.27 to 0.33 µg/g of fresh tissue.
- Treatment
- OTC injection at 0.50 g per treee4
- Outcome
- residue levels of OTCe4
- Value
- 0.27 to 0.33 µg/g of fresh tissuee4
- Setting
- In the fielde4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Liberibacter asiaticus' (CLas) is the causal agent of citrus HLB in Florida”
e4“In the field, OTC injection at 0.50 g per tree resulted in the decline of CLas titers by 1.52 log reduction from 14 to 60 DPA, with residue levels of OTC at 0.27 to 0.33 µg/g of fresh tissue”
Claim · model-written summary
OTC residue levels in leaves were positively correlated with CLas control levels achieved.
- Treatment
- OTC residue levels in leavese5
- Interactor
- CLase0pathogen
- Outcome
- the control levels for CLase5
- Direction
- positive correlationse5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Liberibacter asiaticus' (CLas) is the causal agent of citrus HLB in Florida”
e5“Furthermore, nonlinear modeling revealed significant positive correlations between OTC residue levels in leaves and the control levels for CLas achieved”
Claim · model-written summary
Minimum OTC concentrations required to suppress CLas below the detection limit are 0.68 and 0.86 µg/g.
- Interactor
- CLase0pathogen
- Outcome
- the minimum concentrations of OTC required to suppress CLas populations in planta to below the detection limite6
- Value
- 0.68 and 0.86 µg/ge6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Liberibacter asiaticus' (CLas) is the causal agent of citrus HLB in Florida”
e6“the minimum concentrations of OTC required to suppress CLas populations in planta to below the detection limit are 0.68 and 0.86 µg/g”
Claim · model-written summary
Minimum OTC concentrations for initial inhibition of CLas growth in planta are about 0.17 and 0.215 µg/g in leaf tissue.
- Interactor
- CLase0pathogen
- Outcome
- the minimum concentrations of OTC required for initial inhibition of CLas growth in plantae7
- Value
- ∼0.17 and ∼0.215 µg/ge7
- Setting
- greenhouse and field conditionse7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Liberibacter asiaticus' (CLas) is the causal agent of citrus HLB in Florida”
e7“the minimum concentrations of OTC required for initial inhibition of CLas growth in planta are ∼0.17 and ∼0.215 µg/g in leaf tissues under greenhouse and field conditions, respectively”
Claim · model-written summary
A minimum OTC concentration should be guaranteed in delivery to target CLas in infected citrus plants for effective control.
- Interactor
- CLase0pathogen
- Outcome
- a minimum concentration of OTC should be guaranteed to be delivered to target CLase1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Liberibacter asiaticus' (CLas) is the causal agent of citrus HLB in Florida”
e1“This finding highlights that a minimum concentration of OTC should be guaranteed to be delivered to target CLas in infected plants for effective control of citrus HLB”
The same questions in other papers
oxytetracycline · molecular: metabolites · CitrusPositive and negative results
2 papers in the same direction as this paper · 1 in the opposite direction
- no effect
- positive
- positive
application · molecular: metabolites · CitrusPositive and negative results
10 papers in the same direction as this paper · 3 in the opposite direction
- no effect
- positive
- positive
10 papers more in this group
See all 14 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.