Abstract
Methyl bromide is a common fumigant for effective weed control in polyethylene-mulched vegetable crops. However, the ban on methyl bromide in the United States has created a need to find a suitable alternative. This study investigated the herbicidal efficacy of phenyl isothiocyanate (ITC) as a methyl bromide alternative for weed control in polyethylene-mulched bell pepper during 2006 and 2007. Six rates of phenyl ITC (0, 15, 75, 150, 750, 1,500 kg ha −1 ) under low-density polyethylene (LDPE) or virtually impermeable film (VIF) mulch were tested against yellow nutsedge, Palmer amaranth, and large crabgrass. Additionally, a standard treatment of methyl bromide/chloropicrin (67 : 33%) at 390 kg ha −1 under LDPE mulch was included for comparison. VIF mulch provided no advantage over LDPE mulch in either improving weed control or marketable yield in bell pepper. Unacceptable pepper injury (≥ 60%) occurred at the highest phenyl ITC rate of 1,500 kg ha −1 at 2 WATP in both years, regardless of mulch type. Higher bell pepper injury was observed in 2006 (≥ 36%) than in 2007 (≤ 11%) at 750 kg ha −1 of phenyl ITC. The lower injury in 2007 could be attributed to aeration of beds 48 h prior to transplanting. Regardless of mulch type, phenyl ITC at 2,071 (± 197) and 1,655 (± 309) kg ha −1 was required to control yellow nutsedge, Palmer amaranth, and large crabgrass equivalent to methyl bromide in 2006 and 2007, respectively. Bell pepper marketable yield at all rates of phenyl ITC was lower than methyl bromide in 2006. In contrast, marketable yield in phenyl ITC at 750–kg ha −1 was equivalent to methyl bromide in 2007. It is concluded that phenyl ITC should be applied at least 4.2 times higher rate than methyl bromide for effective weed control, and bed aeration is required to minimize crop injury and yield loss. Additional research is needed to test phenyl ITC in combination with other weed control strategies to obtain effective weed control with acceptable crop safety.
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Claims 12
Claim · model-written summary
VIF mulch gave no weed control advantage over LDPE mulch.
Verbatim
e0“VIF mulch provided no advantage over LDPE mulch in either improving weed control or marketable yield in bell pepper.”
Claim · model-written summary
VIF mulch gave no marketable yield advantage over LDPE mulch.
Verbatim
e0“VIF mulch provided no advantage over LDPE mulch in either improving weed control or marketable yield in bell pepper.”
Claim · model-written summary
The highest phenyl ITC rate caused at least 60% pepper injury at two weeks after transplanting in both years.
- Taxon
- peppere0
- Treatment
- phenyl ITC rate of 1,500 kg ha −1e0
- Outcome
- pepper injurye0
- Direction
- Unacceptablee0
- Value
- ≥ 60%e0
- Qualifier
- 2 WATP in both years, regardless of mulch typee0
Not reportedComparator
Verbatim
e0“Unacceptable pepper injury (≥ 60%) occurred at the highest phenyl ITC rate of 1,500 kg ha −1 at 2 WATP in both years, regardless of mulch type.”
Claim · model-written summary
At 750 kg per hectare phenyl ITC, pepper injury was higher in 2006 than 2007.
Verbatim
e0“Higher bell pepper injury was observed in 2006 (≥ 36%) than in 2007 (≤ 11%) at 750 kg ha −1 of phenyl ITC.”
Claim · model-written summary
Bed aeration may explain lower pepper injury in 2007.
Verbatim
e0“The lower injury in 2007 could be attributed to aeration of beds 48 h prior to transplanting.”
t0“Bell Pepper”
Claim · model-written summary
Phenyl ITC at 2,071 (± 197) kg per hectare matched methyl bromide weed control in 2006.
Verbatim
e0“phenyl ITC at 2,071 (± 197) and 1,655 (± 309) kg ha −1 was required to control yellow nutsedge, Palmer amaranth, and large crabgrass equivalent to methyl bromide in 2006 and 2007, respectively.”
t0“Bell Pepper”
e1“2,071 (± 197) and 1,655 (± 309) kg ha −1”
Claim · model-written summary
Phenyl ITC at 1,655 (± 309) kg per hectare matched methyl bromide weed control in 2007.
Verbatim
e0“phenyl ITC at 2,071 (± 197) and 1,655 (± 309) kg ha −1 was required to control yellow nutsedge, Palmer amaranth, and large crabgrass equivalent to methyl bromide in 2006 and 2007, respectively.”
t0“Bell Pepper”
e1“2,071 (± 197) and 1,655 (± 309) kg ha −1”
Claim · model-written summary
Bell pepper yield at all phenyl ITC rates was below methyl bromide in 2006.
Verbatim
e0“Bell pepper marketable yield at all rates of phenyl ITC was lower than methyl bromide in 2006.”
Claim · model-written summary
Bell pepper yield at 750 kg per hectare phenyl ITC equaled methyl bromide in 2007.
Verbatim
e0“marketable yield in phenyl ITC at 750–kg ha −1 was equivalent to methyl bromide in 2007.”
t0“Bell Pepper”
Claim · model-written summary
The authors recommend phenyl ITC at least 4.2 times the methyl bromide rate for effective weed control.
Verbatim
e0“phenyl ITC should be applied at least 4.2 times higher rate than methyl bromide for effective weed control”
t0“Bell Pepper”
Claim · model-written summary
The authors recommend bed aeration to limit pepper injury and yield loss.
Verbatim
e0“bed aeration is required to minimize crop injury and yield loss.”
t0“Bell Pepper”
Claim · model-written summary
The authors call for testing phenyl ITC with other weed control approaches for effective control and crop safety.
Verbatim
e0“Additional research is needed to test phenyl ITC in combination with other weed control strategies to obtain effective weed control with acceptable crop safety.”
t0“Bell Pepper”
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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.