Abstract
Expanding preemergence herbicide registrations to include over-the-top (OTT) applications of S -metolachlor in pumpkins could extend the duration of residual weed control, which would provide the crop with a competitive advantage over weeds. In 2021, field trials were conducted at two locations in Indiana (IN) and a single location each in Delaware (DE), Maryland (MD), Michigan (MI), North Carolina (NC), North Dakota (ND), New Jersey (NJ), New York (NY), Ohio (OH), and Pennsylvania (PA) to evaluate the safety of S -metolachlor OTT in jack-o-lantern varieties across multiple production regions. All locations included treatments consisting of S -metolachlor applied at 1.4 and 2.8 kg·ha −1 at one of two timings (early or late). At some locations, additional treatments included halosulfuron-methyl at 26 g·ha −1 a.i., combined with 0.25% (v/v) nonionic surfactant tank-mixed with S- metolachlor and applied as previously described. With the exception of MI [20 d after planting (DAP)], early applications were made 12 to 15 DAP. Late applications were made between 25 and 31 DAP at all locations. S -metolachlor applied at 1.4 or 2.8 kg·ha −1 caused less than 10% crop injury within a week of application, which declined over time. The highest injury levels were observed with early applications and on loamy sand soils containing ≤2% organic matter. The addition of halosulfuron-methyl significantly increased crop injury to 15% at 1 week after treatment (WAT), with early applications causing more severe damage (25%) than late applications (11%), although pumpkins recovered completely by 6 WAT. Although total and marketable fruit yields were unaffected by herbicide treatments, adding halosulfuron-methyl to OTT application reduced marketable fruit numbers to 84% of the standard control and decreased the proportion of large fruits from 97% to 65%. S -metolachlor applied at 2.8 kg·ha −1 tended to reduce the percentage of commercial-grade fruit and, depending on application timing, increased the proportion of small fruit. Results indicate that applications of S- metolachlor at 1.4 kg·ha −1 a.i. applied 12 to 31 DAP causes minimal crop injury and yield loss and could be a valuable tool for extending residual weed control in pumpkins.
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Claims 14
Claim · model-written summary
S-metolachlor at 1.4 kg per hectare caused less than 10% initial crop injury, which declined.
- Taxon
- Pumpkint0
- Treatment
- S -metolachlor applied at 1.4e0
- Outcome
- crop injurye0
- Direction
- declinede0
- Value
- less than 10%e0
Not reportedComparator
Verbatim
t0“Pumpkin”
e0“S -metolachlor applied at 1.4 or 2.8 kg·ha −1 caused less than 10% crop injury within a week of application, which declined over time.”
Claim · model-written summary
S-metolachlor at 2.8 kg per hectare caused less than 10% initial crop injury, which declined.
Not reportedComparator
Verbatim
t0“Pumpkin”
e0“S -metolachlor applied at 1.4 or 2.8 kg·ha −1 caused less than 10% crop injury within a week of application, which declined over time.”
Claim · model-written summary
Early applications had the highest injury.
Not reportedComparator
Verbatim
t0“Pumpkin”
e0“The highest injury levels were observed with early applications and on loamy sand soils containing ≤2% organic matter.”
Claim · model-written summary
Injury was highest on loamy sand with at most 2% organic matter.
- Taxon
- Pumpkint0
- Treatment
- early applicationse0
- Outcome
- injury levelse0
- Direction
- higheste0
- Qualifier
- loamy sand soils containing ≤2% organic mattere0
Not reportedComparator
Verbatim
t0“Pumpkin”
e0“The highest injury levels were observed with early applications and on loamy sand soils containing ≤2% organic matter.”
Claim · model-written summary
Adding halosulfuron-methyl increased crop injury to 15% after one week.
- Taxon
- Pumpkint0
- Treatment
- addition of halosulfuron-methyle0
- Outcome
- crop injurye0
- Direction
- increasede0
- Value
- 15%e0
Not reportedComparator
Verbatim
t0“Pumpkin”
e0“The addition of halosulfuron-methyl significantly increased crop injury to 15% at 1 week after treatment (WAT)”
Claim · model-written summary
Early mixed applications caused 25% damage.
Verbatim
t0“Pumpkin”
e0“early applications causing more severe damage (25%) than late applications (11%)”
Claim · model-written summary
Late mixed applications caused 11% damage.
Verbatim
t0“Pumpkin”
e0“early applications causing more severe damage (25%) than late applications (11%)”
Claim · model-written summary
Pumpkins completely recovered by six weeks after treatment.
Not reportedTreatmentComparatorDirection
Verbatim
t0“Pumpkin”
e0“although pumpkins recovered completely by 6 WAT.”
Claim · model-written summary
Total and marketable fruit yields were unaffected by herbicide treatments.
- Taxon
- Pumpkint0
- Treatment
- herbicide treatmentse0
- Outcome
- total and marketable fruit yieldse0
- Direction
- unaffectede0
Not reportedComparator
Verbatim
t0“Pumpkin”
e0“total and marketable fruit yields were unaffected by herbicide treatments”
Claim · model-written summary
Adding halosulfuron-methyl reduced marketable fruit number to 84% of standard control.
Verbatim
t0“Pumpkin”
e0“adding halosulfuron-methyl to OTT application reduced marketable fruit numbers to 84% of the standard control”
Claim · model-written summary
Adding halosulfuron-methyl decreased large-fruit proportion from 97% to 65%.
Not reportedTreatmentComparator
Verbatim
t0“Pumpkin”
e0“decreased the proportion of large fruits from 97% to 65%.”
Claim · model-written summary
S-metolachlor at 2.8 kg per hectare tended to reduce commercial-grade fruit percentage.
- Taxon
- Pumpkint0
- Treatment
- S -metolachlor applied at 2.8 kg·ha −1e0
- Outcome
- percentage of commercial-grade fruite0
- Direction
- reducee0
Not reportedComparator
Verbatim
t0“Pumpkin”
e0“S -metolachlor applied at 2.8 kg·ha −1 tended to reduce the percentage of commercial-grade fruit”
Claim · model-written summary
Depending on timing, S-metolachlor at 2.8 kg per hectare increased small-fruit proportion.
- Taxon
- Pumpkint0
- Treatment
- S -metolachlor applied at 2.8 kg·ha −1e0
- Outcome
- proportion of small fruite0
- Direction
- increasede0
- Qualifier
- depending on application timinge0
Not reportedComparator
Verbatim
t0“Pumpkin”
e0“S -metolachlor applied at 2.8 kg·ha −1 tended to reduce the percentage of commercial-grade fruit and, depending on application timing, increased the proportion of small fruit.”
Claim · model-written summary
The authors conclude that 1.4 kg per hectare applied 12 to 31 days after planting causes minimal injury and yield loss and may extend residual weed control.
Verbatim
t0“Pumpkin”
e0“S- metolachlor at 1.4 kg·ha −1 a.i. applied 12 to 31 DAP causes minimal crop injury and yield loss and could be a valuable tool for extending residual weed control in pumpkins.”
The same questions in other papers
metolachlor · crop injury · Cucurbita (pumpkins)Positive and negative results
1 paper in the same direction as this paper · 1 in the opposite direction
- negative
- positive
Halosulfuron-methyl · crop injury · Cucurbita (pumpkins)Positive and negative results
6 papers in the same direction as this paper · 1 in the opposite direction
- positive
- no effect
- negative
4 papers more in this group
See all 8 papers →Halosulfuron-methyl · quality: postharvest · Cucurbita (pumpkins)Results agree
1 paper in the same direction as this paper
- negative
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.