Abstract
Data were collected on 36 variables including application, environmental, edaphic, and plant conditions during a 3-year study of aerial brush control treatments at 79 sites. These then were correlated with defoliation responses of blackjack oak ( Quercus marilandica Muenchh.) and post oak ( Quercus stellata Wangenh.) to (2,4,5-trichlorophenoxy)acetic acid (2,4,5-T). The stage of oak growth was of primary importance in obtaining maximum defoliation with 2,4,5-T; the oaks were most susceptible 6 to 8 weeks after the last killing frost. Air temperatures above 90 F, relative humidity below 60%, poor spray coverage and swath widths greater than 50 ft significantly reduced defoliation by 2,4,5-T. Total rainfall during the month before spray application was positively correlated with defoliation by 2,4,5-T, but correlations with rainfall for other time intervals before and after spraying were not significant. Wind above 6 mph at the time of treatment slightly reduced 2,4,5-T effectiveness, but wind direction and dew at spray time did not influence herbicide activity. Application rates of less than 1.75 lb/A were not as effective as higher rates. Aircraft design, spray-water carrier constituents, soil type, soil depth, soil temperature, and topography had no apparent influence on defoliation of oaks by 2,4,5-T.
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Claims 13
Claim · model-written summary
Oak growth stage was the main factor in maximum 2,4,5-T defoliation.
QuercusOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The stage of oak growth was of primary importance in obtaining maximum defoliation with 2,4,5-T”
Claim · model-written summary
Oaks were most susceptible six to eight weeks after the last killing frost.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the oaks were most susceptible 6 to 8 weeks after the last killing frost”
Claim · model-written summary
Air temperatures above 90 F reduced herbicide defoliation.
Not reportedTaxon
Verbatim
e0“Air temperatures above 90 F, relative humidity below 60%, poor spray coverage and swath widths greater than 50 ft significantly reduced defoliation by 2,4,5-T”
Claim · model-written summary
Relative humidity below 60% reduced herbicide defoliation.
Not reportedTaxon
Verbatim
e0“Air temperatures above 90 F, relative humidity below 60%, poor spray coverage and swath widths greater than 50 ft significantly reduced defoliation by 2,4,5-T”
Claim · model-written summary
Poor spray coverage reduced herbicide defoliation.
Not reportedTaxon
Verbatim
e0“poor spray coverage and swath widths greater than 50 ft significantly reduced defoliation by 2,4,5-T”
Claim · model-written summary
Swath widths greater than 50 ft reduced herbicide defoliation.
Not reportedTaxon
Verbatim
e0“swath widths greater than 50 ft significantly reduced defoliation by 2,4,5-T”
Claim · model-written summary
Rainfall in the month before spraying correlated positively with defoliation.
- Outcome
- defoliatione0
- Direction
- positively correlatede0
- Setting
- Total rainfall during the month before spray applicatione0
Not reportedTaxon
Verbatim
e0“Total rainfall during the month before spray application was positively correlated with defoliation by 2,4,5-T”
Claim · model-written summary
Rainfall in other intervals was not significantly correlated with defoliation.
Not reportedTaxonDirection
Verbatim
e0“correlations with rainfall for other time intervals before and after spraying were not significant”
Claim · model-written summary
Wind above 6 mph slightly reduced herbicide effectiveness.
Not reportedTaxon
Verbatim
e0“Wind above 6 mph at the time of treatment slightly reduced 2,4,5-T effectiveness”
Claim · model-written summary
Wind direction did not influence herbicide activity.
Not reportedTaxon
Verbatim
e0“wind direction and dew at spray time did not influence herbicide activity”
Claim · model-written summary
Dew at spray time did not influence herbicide activity.
Not reportedTaxon
Verbatim
e0“wind direction and dew at spray time did not influence herbicide activity”
Claim · model-written summary
Application rates below 1.75 lb/A were less effective than higher rates.
- Treatment
- Application rates of less than 1.75 lb/Ae0
- Outcome
- not as effectivee0
- Direction
- not as effectivee0
- Comparator
- higher ratese0
Not reportedTaxon
Verbatim
e0“Application rates of less than 1.75 lb/A were not as effective as higher rates”
Claim · model-written summary
Aircraft design, carrier constituents, soil factors and topography had no apparent influence on oak defoliation.
- Treatment
- Aircraft design, spray-water carrier constituents, soil type, soil depth, soil temperature, and topographye0
- Outcome
- defoliation of oakse0
- Direction
- no apparent influencee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Aircraft design, spray-water carrier constituents, soil type, soil depth, soil temperature, and topography had no apparent influence on defoliation of oaks by 2,4,5-T”