Abstract
Limited information exists on the sensitivity of winter wheat to clopyralid applied in the fall, spring, or sequentially [fall followed by (fb) spring] under Ontario environmental conditions. Six field experiments were conducted over two years (2023 and 2024) near Exeter and Ridgetown, Ontario, to evaluate the effects of clopyralid (100, 200, and 400 g ai ha-1) applied in the fall, spring, or sequentially (fall fb spring) on winter wheat injury, height, seed moisture content, and yield. No visible injury was observed at 1, 2, and 4 weeks after application with clopyralid applied in the fall, spring, or sequentially at the evaluated rates. Clopyralid applied in the fall at all rates caused no injury to winter wheat; in contrast, when applied in the spring clopyralid caused 3, 7, and 14% visible injury at 100, 200, and 400 g ai ha-1, respectively. Sequential applications of clopyralid (fall fb spring) resulted in 4, 9, and 17% visible injury at the same respective rates. Clopyralid application at 100, 200, and 400 g ai ha-1 in the fall, spring, or sequentially had no significant effect on winter wheat height or seed moisture content. Clopyralid applied at 100, 200, and 400 g ai ha-1 in the fall did not affect winter wheat yield. Clopyralid applied at 100 and 200 g ai ha-1 in the spring had no impact on yield, but when applied at 400 g ai ha-1, it reduced winter wheat yield by 19%. Sequential applications at 100 fb 100 and 200 fb 200 g ai ha-1 also had no significant effect on winter wheat yield, while the 400 fb 400 g ai ha-1 treatment reduced winter wheat yield by 17%. These results conclude that clopyralid applied in the fall caused no visible wheat injury and no decrease in wheat height or yield. Clopyralid, applied in the spring at 100 and 200 g ai ha-1 caused 3 and 7% visible wheat injury, respectively but no decrease in wheat height or yield. Clopyralid applied in the spring at 400 g ai ha-1 caused up to 17% visible wheat injury and reduced wheat yield by up to 19%. These results conclude that clopyralid at the label rate applied in the fall, spring, or sequentially has no adverse effect on winter wheat; however, where there is a spray overlap clopyralid can cause unacceptable wheat injury and yield loss.
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Claims 16
Claim · model-written summary
No visible injury was observed at 1, 2, or 4 weeks after clopyralid treatment.
- Taxon
- winter wheat
Triticum aestivume1 - Outcome
- No visible injurye0
- Qualifier
- 1, 2, and 4 weeks after applicatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“No visible injury was observed at 1, 2, and 4 weeks after application with clopyralid applied in the fall, spring, or sequentially at the evaluated rates.”
e1“sensitivity of winter wheat to clopyralid”
Claim · model-written summary
Fall clopyralid application caused no winter wheat injury at any tested rate.
- Taxon
- winter wheatTriticum aestivume0
- Treatment
- Clopyralid applied in the fall at all ratese0
- Outcome
- injurye0
- Direction
- no injurye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Clopyralid applied in the fall at all rates caused no injury to winter wheat”
Claim · model-written summary
Spring clopyralid at 100 g ai ha-1 caused 3% visible wheat injury.
- Taxon
- winter wheatTriticum aestivume1
- Treatment
- clopyralide0
- Outcome
- visible injurye0
- Direction
- causede0
- Value
- 3e0
- Qualifier
- 100, 200, and 400 g ai ha-1e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“when applied in the spring clopyralid caused 3, 7, and 14% visible injury at 100, 200, and 400 g ai ha-1, respectively.”
e1“sensitivity of winter wheat to clopyralid”
Claim · model-written summary
Spring clopyralid at 200 g ai ha-1 caused 7% visible wheat injury.
- Taxon
- winter wheatTriticum aestivume1
- Treatment
- clopyralide0
- Outcome
- visible injurye0
- Direction
- causede0
- Value
- 7e0
- Qualifier
- 100, 200, and 400 g ai ha-1e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“when applied in the spring clopyralid caused 3, 7, and 14% visible injury at 100, 200, and 400 g ai ha-1, respectively.”
e1“sensitivity of winter wheat to clopyralid”
Claim · model-written summary
Spring clopyralid at 400 g ai ha-1 caused 14% visible wheat injury.
- Taxon
- winter wheatTriticum aestivume1
- Treatment
- clopyralide0
- Outcome
- visible injurye0
- Direction
- causede0
- Value
- 14%e0
- Qualifier
- 100, 200, and 400 g ai ha-1e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“when applied in the spring clopyralid caused 3, 7, and 14% visible injury at 100, 200, and 400 g ai ha-1, respectively.”
e1“sensitivity of winter wheat to clopyralid”
Claim · model-written summary
Sequential clopyralid at 100 g ai ha-1 caused 4% visible wheat injury.
- Taxon
- winter wheatTriticum aestivume1
- Treatment
- Sequential applications of clopyralid (fall fb spring)e0
- Outcome
- visible injurye0
- Direction
- resulted ine0
- Value
- 4e0
- Qualifier
- 100, 200, and 400 g ai ha-1e2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Sequential applications of clopyralid (fall fb spring) resulted in 4, 9, and 17% visible injury at the same respective rates.”
e1“sensitivity of winter wheat to clopyralid”
e2“clopyralid (100, 200, and 400 g ai ha-1)”
Claim · model-written summary
Sequential clopyralid at 200 g ai ha-1 caused 9% visible wheat injury.
- Taxon
- winter wheatTriticum aestivume1
- Treatment
- Sequential applications of clopyralid (fall fb spring)e0
- Outcome
- visible injurye0
- Direction
- resulted ine0
- Value
- 9e0
- Qualifier
- 100, 200, and 400 g ai ha-1e2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Sequential applications of clopyralid (fall fb spring) resulted in 4, 9, and 17% visible injury at the same respective rates.”
e1“sensitivity of winter wheat to clopyralid”
e2“clopyralid (100, 200, and 400 g ai ha-1)”
Claim · model-written summary
Sequential clopyralid at 400 g ai ha-1 caused 17% visible wheat injury.
- Taxon
- winter wheatTriticum aestivume1
- Treatment
- Sequential applications of clopyralid (fall fb spring)e0
- Outcome
- visible injurye0
- Direction
- resulted ine0
- Value
- 17%e0
- Qualifier
- 100, 200, and 400 g ai ha-1e2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Sequential applications of clopyralid (fall fb spring) resulted in 4, 9, and 17% visible injury at the same respective rates.”
e1“sensitivity of winter wheat to clopyralid”
e2“clopyralid (100, 200, and 400 g ai ha-1)”
Claim · model-written summary
Across rates and timings, clopyralid had no significant effect on wheat height or seed moisture.
- Taxon
- winter wheatTriticum aestivume0
- Treatment
- Clopyralid application at 100, 200, and 400 g ai ha-1 in the fall, spring, or sequentiallye0
- Outcome
- winter wheat height or seed moisture contente0
- Direction
- no significant effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Clopyralid application at 100, 200, and 400 g ai ha-1 in the fall, spring, or sequentially had no significant effect on winter wheat height or seed moisture content.”
Claim · model-written summary
Fall clopyralid at all tested rates did not affect wheat yield.
- Taxon
- winter wheatTriticum aestivume0
- Treatment
- Clopyralid applied at 100, 200, and 400 g ai ha-1 in the falle0
- Outcome
- winter wheat yielde0
- Direction
- did not affecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Clopyralid applied at 100, 200, and 400 g ai ha-1 in the fall did not affect winter wheat yield.”
Claim · model-written summary
Spring clopyralid at 100 or 200 g ai ha-1 had no impact on wheat yield.
- Taxon
- winter wheatTriticum aestivume1
- Treatment
- Clopyralid applied at 100 and 200 g ai ha-1 in the springe0
- Outcome
- yielde0
- Direction
- no impacte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Clopyralid applied at 100 and 200 g ai ha-1 in the spring had no impact on yield”
e1“sensitivity of winter wheat to clopyralid”
Claim · model-written summary
Spring clopyralid at 400 g ai ha-1 reduced wheat yield by 19%.
- Taxon
- winter wheatTriticum aestivume0
- Treatment
- 400 g ai ha-1e0
- Outcome
- winter wheat yielde0
- Direction
- reducede0
- Value
- 19%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“when applied at 400 g ai ha-1, it reduced winter wheat yield by 19%.”
e1“Clopyralid applied at 100 and 200 g ai ha-1 in the spring”
Claim · model-written summary
Sequential clopyralid at 100 fb 100 or 200 fb 200 g ai ha-1 had no significant wheat-yield effect.
- Taxon
- winter wheatTriticum aestivume0
- Treatment
- Sequential applications at 100 fb 100 and 200 fb 200 g ai ha-1e0
- Outcome
- winter wheat yielde0
- Direction
- no significant effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Sequential applications at 100 fb 100 and 200 fb 200 g ai ha-1 also had no significant effect on winter wheat yield”
Claim · model-written summary
Sequential clopyralid at 400 fb 400 g ai ha-1 reduced wheat yield by 17%.
- Taxon
- winter wheatTriticum aestivume0
- Treatment
- 400 fb 400 g ai ha-1 treatmente0
- Outcome
- winter wheat yielde0
- Direction
- reducede0
- Value
- 17%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the 400 fb 400 g ai ha-1 treatment reduced winter wheat yield by 17%”
Claim · model-written summary
The authors conclude that label-rate clopyralid applied in fall, spring or sequentially has no adverse effect on winter wheat.
- Taxon
- winter wheatTriticum aestivume0
- Outcome
- clopyralid at the label rate applied in the fall, spring, or sequentiallye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“clopyralid at the label rate applied in the fall, spring, or sequentially has no adverse effect on winter wheat”
Claim · model-written summary
The authors warn that clopyralid spray overlap can cause unacceptable wheat injury and yield loss.
- Taxon
- winter wheatTriticum aestivume1
- Outcome
- spray overlap clopyralide0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“where there is a spray overlap clopyralid can cause unacceptable wheat injury and yield loss”
e1“sensitivity of winter wheat to clopyralid”
The same questions in other papers
clopyralid · yield · Triticum aestivum (wheat)Results differ
4 papers in the same direction as this paper · 1 in the opposite direction
- positive
- negative
- no effect
2 papers more in this group
See all 6 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.