Abstract
Canola ( Brassica napus ) crops for grazing and grain (dual‐purpose) production provide an economic break‐crop alternative for dual‐purpose cereals in Australian mixed farming systems. Infection by Leptosphaeria maculans is the most prevalent disease in Australian canola crops with airborne inoculum released throughout the autumn and winter when crops are grazed. Glasshouse and field experiments were conducted to investigate the effect of mechanical defoliation (simulated grazing) on disease severity at plant maturity. In glasshouse experiments, stem canker severity increased from 4% to 24% in severely defoliated plants, but light defoliation had no effect compared with undefoliated control plants. Disease severity was increased with defoliation in all field experiments. Defoliation increased crown canker severity from 22.6% to 39.3% at Wagga Wagga and from 3.0% to 7.1% at Canberra and lodging from 9.6% to 11.9% at Naracoorte in the same set of cultivars assessed at each site. The increase in disease severity with defoliation was less in canola lines with moderate to high levels of stem canker resistance. Plants defoliated before stem elongation tended to develop less disease than those defoliated during the reproductive phase of plant growth. These findings suggest that the impact of grazing on L. maculans infection of canola crops can be minimised by sowing cultivars with a high level of stem canker resistance and grazing during the vegetative stage of plant growth prior to stem elongation. Further research is required to determine whether these management strategies are applicable in canola crops defoliated by grazing animals.
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Claims 10
Claim · model-written summary
In glasshouse experiments, severe defoliation increased stem canker severity from 4% to 24% compared with undefoliated plants.
- Taxon
- Brassica napus
Brassica napuse0 - Treatment
- severely defoliatede2
- Interactor
- Leptosphaeria maculans
Plenodomus lingame1pathogen - Outcome
- stem canker severitye2
- Direction
- increasede2
- Value
- from 4% to 24%e2
- Comparator
- undefoliated control plantse2
- Setting
- glasshouse experimentse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_Brassica_napus_-_Habit.jpg?width=500)

Verbatim
e0“Canola ( Brassica napus ) crops for grazing and grain”
e1“Infection by Leptosphaeria maculans is the most prevalent disease in Australian canola crops”
e2“In glasshouse experiments, stem canker severity increased from 4% to 24% in severely defoliated plants, but light defoliation had no effect compared with undefoliated control plants”
Claim · model-written summary
Light defoliation had no effect on stem canker severity in glasshouse experiments compared with undefoliated control plants.
- Taxon
- Brassica napus
Brassica napuse0 - Treatment
- light defoliatione2
- Outcome
- stem canker severitye2
- Direction
- had no effecte2
- Comparator
- undefoliated control plantse2
- Setting
- glasshouse experimentse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_Brassica_napus_-_Habit.jpg?width=500)
Verbatim
e0“Canola ( Brassica napus ) crops for grazing and grain”
e2“In glasshouse experiments, stem canker severity increased from 4% to 24% in severely defoliated plants, but light defoliation had no effect compared with undefoliated control plants”
Claim · model-written summary
Defoliation increased disease severity in all field experiments.
- Taxon
- Brassica napus
Brassica napuse0 - Treatment
- defoliatione3
- Interactor
- Leptosphaeria maculans
Plenodomus lingame1pathogen - Outcome
- Disease severitye3
- Direction
- increasede3
- Setting
- all field experimentse3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_Brassica_napus_-_Habit.jpg?width=500)

Verbatim
e0“Canola ( Brassica napus ) crops for grazing and grain”
e1“Infection by Leptosphaeria maculans is the most prevalent disease in Australian canola crops”
e3“Disease severity was increased with defoliation in all field experiments”
Claim · model-written summary
Defoliation increased crown canker severity at Wagga Wagga from 22.6% to 39.3%.
- Taxon
- Brassica napus
Brassica napuse0 - Treatment
- Defoliatione4
- Interactor
- Leptosphaeria maculans
Plenodomus lingame1pathogen - Outcome
- crown canker severitye4
- Direction
- increasede4
- Value
- from 22.6% to 39.3%e4
- Setting
- Wagga Waggae4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_Brassica_napus_-_Habit.jpg?width=500)

Verbatim
e0“Canola ( Brassica napus ) crops for grazing and grain”
e1“Infection by Leptosphaeria maculans is the most prevalent disease in Australian canola crops”
e4“Defoliation increased crown canker severity from 22.6% to 39.3% at Wagga Wagga and from 3.0% to 7.1% at Canberra and lodging from 9.6% to 11.9% at Naracoorte in the same set of cultivars assessed at each site”
Claim · model-written summary
Defoliation increased crown canker severity at Canberra from 3.0% to 7.1%.
- Taxon
- Brassica napus
Brassica napuse0 - Treatment
- Defoliatione4
- Interactor
- Leptosphaeria maculans
Plenodomus lingame1pathogen - Outcome
- crown canker severitye4
- Direction
- increasede4
- Value
- from 3.0% to 7.1%e4
- Setting
- Canberrae4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_Brassica_napus_-_Habit.jpg?width=500)

Verbatim
e0“Canola ( Brassica napus ) crops for grazing and grain”
e1“Infection by Leptosphaeria maculans is the most prevalent disease in Australian canola crops”
e4“Defoliation increased crown canker severity from 22.6% to 39.3% at Wagga Wagga and from 3.0% to 7.1% at Canberra and lodging from 9.6% to 11.9% at Naracoorte in the same set of cultivars assessed at each site”
Claim · model-written summary
Defoliation increased lodging at Naracoorte from 9.6% to 11.9%.
- Taxon
- Brassica napus
Brassica napuse0 - Treatment
- Defoliatione4
- Outcome
- lodginge4
- Direction
- increasede4
- Value
- from 9.6% to 11.9%e4
- Setting
- Naracoortee4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_Brassica_napus_-_Habit.jpg?width=500)
Verbatim
e0“Canola ( Brassica napus ) crops for grazing and grain”
e4“Defoliation increased crown canker severity from 22.6% to 39.3% at Wagga Wagga and from 3.0% to 7.1% at Canberra and lodging from 9.6% to 11.9% at Naracoorte in the same set of cultivars assessed at each site”
Claim · model-written summary
The increase in disease severity with defoliation was smaller in canola lines with moderate to high stem canker resistance.
- Taxon
- canola
Brassica napus var. napuse0 - Material
- canola lines with moderate to high levels of stem canker resistancee5
- Treatment
- defoliatione5
- Outcome
- increase in disease severity with defoliatione5
- Direction
- lesse5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“Canola ( Brassica napus ) crops for grazing and grain”
e5“The increase in disease severity with defoliation was less in canola lines with moderate to high levels of stem canker resistance”
Claim · model-written summary
Plants defoliated before stem elongation tended to develop less disease than plants defoliated during the reproductive phase.
- Taxon
- Brassica napus
Brassica napuse0 - Treatment
- defoliated before stem elongatione6
- Outcome
- diseasee6
- Direction
- lesse6
- Qualifier
- tended toe6
- Comparator
- defoliated during the reproductive phasee6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_Brassica_napus_-_Habit.jpg?width=500)
Verbatim
e0“Canola ( Brassica napus ) crops for grazing and grain”
e6“Plants defoliated before stem elongation tended to develop less disease than those defoliated during the reproductive phase of plant growth”
Claim · model-written summary
Sowing cultivars with a high level of stem canker resistance can minimise the impact of grazing on L. maculans infection in canola.
- Taxon
- canola
Brassica napus var. napuse0 - Treatment
- sowing cultivars with a high level of stem canker resistancee7
- Outcome
- impact of grazing on L. maculans infectione7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“Canola ( Brassica napus ) crops for grazing and grain”
e7“the impact of grazing on L. maculans infection of canola crops can be minimised by sowing cultivars with a high level of stem canker resistance and grazing during the vegetative stage of plant growth prior to stem elongation”
Claim · model-written summary
Grazing during the vegetative stage before stem elongation can minimise the impact of grazing on L. maculans infection in canola.
- Taxon
- canola
Brassica napus var. napuse0 - Treatment
- grazing during the vegetative stage of plant growth prior to stem elongatione7
- Outcome
- impact of grazing on L. maculans infectione7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“Canola ( Brassica napus ) crops for grazing and grain”
e7“the impact of grazing on L. maculans infection of canola crops can be minimised by sowing cultivars with a high level of stem canker resistance and grazing during the vegetative stage of plant growth prior to stem elongation”
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