Abstract
Apple orchardists in the United States protect their crops from numerous insects and diseases using foliar pesticide applications to produce blemish-free produce; however, doing so incurs significant labor and input costs. Variable-rate spray application technology used at the default spray rate has successfully reduced pesticide volume and, consequently, input costs in orchards and nurseries while effectively controlling several diseases and insects. Our objectives were to evaluate spray characteristics and the pest control efficacy of a sprayer operated in the variable-rate mode at a lower rate than the default rate and compare them with those associated with the conventional constant-rate spray mode. Through preliminary experiments, a reduced spray rate of 0.05 L·m −3 of crop volume, which equated to 321.1 L·ha −1 , was selected and compared with a conventional constant-rate of 808 L·ha −1 using a sprayer retrofitted with variable-rate spray technology and operated in the two different modes throughout two growing seasons. Foliage was scouted biweekly for diseases and two arthropods, and apples were scouted weekly for disease. The variable-rate mode reduced the pesticide volume applied by 58% and maintained pesticide coverage at or above the overspray threshold at all canopy locations except for one. Nontarget ground applications were greatly reduced using the variable-rate mode. Foliar disease measured as leaf spot incidence and leaf spot count severity was unaffected by the spray mode. Fruit rot incidence, fruit rot severity, and disease index for fruit were also unaffected by the spray mode. Fruit disease index, which incorporates both incidence and severity measurements, remained low throughout both seasons. Disease progression was assessed by calculating the area under the disease progress curve (AUDPC). The foliar AUDPC was significantly higher in the variable-rate treatment at the middle of hill location, but not at the bottom or the top of the hill, compared with that of the constant-rate treatment. The fruit AUDPC was unaffected by treatment. Although normally common in apple orchards, neither of the two arthropods was detected on any date. The utility and limitations of existing spray characterization metrics as well as the need for yet-to-be-developed metrics are discussed.
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Claims 10
Claim · model-written summary
Variable-rate spraying at a reduced rate reduces the pesticide volume applied in apple by 58% relative to constant-rate spraying.
- Taxon
- apple
Malus domesticae0 - Treatment
- variable-rate modee1
- Outcome
- pesticide volume appliede1
- Direction
- reducede1
- Value
- 58%e1
- Comparator
- conventional constant-ratee2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Apple orchardists in the United States protect their crops from numerous insects and diseases”
e1“The variable-rate mode reduced the pesticide volume applied by 58%”
e2“a conventional constant-rate”
Claim · model-written summary
Variable-rate spraying maintains pesticide coverage at or above the overspray threshold at all canopy locations except one.
- Taxon
- appleMalus domesticae0
- Treatment
- variable-rate modee1
- Outcome
- pesticide coveragee2
- Direction
- maintainede2
- Qualifier
- at or above the overspray threshold at all canopy locations except for onee2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Apple orchardists in the United States protect their crops from numerous insects and diseases”
e1“The variable-rate mode reduced the pesticide volume applied by 58%”
e2“maintained pesticide coverage at or above the overspray threshold at all canopy locations except for one”
Claim · model-written summary
Variable-rate spraying greatly reduces nontarget ground applications.
- Taxon
- appleMalus domesticae0
- Treatment
- variable-rate modee1
- Outcome
- Nontarget ground applicationse1
- Direction
- greatly reducede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Apple orchardists in the United States protect their crops from numerous insects and diseases”
e1“Nontarget ground applications were greatly reduced using the variable-rate mode”
Claim · model-written summary
Spray mode does not affect leaf spot incidence or leaf spot count severity in apple foliage.
- Taxon
- appleMalus domesticae0
- Treatment
- spray modee1
- Outcome
- leaf spot incidence and leaf spot count severitye1
- Direction
- unaffectede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Apple orchardists in the United States protect their crops from numerous insects and diseases”
e1“Foliar disease measured as leaf spot incidence and leaf spot count severity was unaffected by the spray mode”
Claim · model-written summary
Spray mode does not affect fruit rot incidence, fruit rot severity or fruit disease index in apple.
- Taxon
- appleMalus domesticae0
- Treatment
- spray modee1
- Outcome
- Fruit rot incidence, fruit rot severity, and disease index for fruite1
- Direction
- unaffectede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Apple orchardists in the United States protect their crops from numerous insects and diseases”
e1“Fruit rot incidence, fruit rot severity, and disease index for fruit were also unaffected by the spray mode”
Claim · model-written summary
Fruit disease index remained low throughout both seasons.
- Taxon
- appleMalus domesticae0
- Outcome
- Fruit disease indexe1
- Qualifier
- remained low throughout both seasonse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Apple orchardists in the United States protect their crops from numerous insects and diseases”
e1“Fruit disease index, which incorporates both incidence and severity measurements, remained low throughout both seasons”
Claim · model-written summary
Foliar AUDPC is significantly higher under variable-rate than constant-rate spraying at the middle of the hill.
- Taxon
- appleMalus domesticae0
- Treatment
- variable-rate treatmente1
- Outcome
- foliar AUDPCe1
- Direction
- highere1
- Qualifier
- at the middle of hill locatione1
- Comparator
- constant-rate treatmente1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Apple orchardists in the United States protect their crops from numerous insects and diseases”
e1“The foliar AUDPC was significantly higher in the variable-rate treatment at the middle of hill location, but not at the bottom or the top of the hill, compared with that of the constant-rate treatment”
Claim · model-written summary
Foliar AUDPC does not differ between spray modes at the bottom or the top of the hill.
- Taxon
- appleMalus domesticae0
- Treatment
- variable-rate treatmente1
- Outcome
- foliar AUDPCe1
- Direction
- no_changeinferrede1
- Qualifier
- at the bottom or the top of the hille1
- Comparator
- constant-rate treatmente1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Apple orchardists in the United States protect their crops from numerous insects and diseases”
e1“The foliar AUDPC was significantly higher in the variable-rate treatment at the middle of hill location, but not at the bottom or the top of the hill, compared with that of the constant-rate treatment”
Claim · model-written summary
Fruit AUDPC is not affected by spray mode.
- Taxon
- appleMalus domesticae0
- Treatment
- treatmente1
- Outcome
- fruit AUDPCe1
- Direction
- unaffectede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Apple orchardists in the United States protect their crops from numerous insects and diseases”
e1“The fruit AUDPC was unaffected by treatment”
Claim · model-written summary
Neither of the two arthropods common in apple orchards was detected on any date.
- Taxon
- appleMalus domesticae0
- Outcome
- arthropodse1
- Qualifier
- neither of the two arthropods was detected on any datee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Apple orchardists in the United States protect their crops from numerous insects and diseases”
e1“neither of the two arthropods was detected on any date”
The same questions in other papers
application · disease · Malus domestica (apple)Positive and negative results
26 papers in the same direction as this paper · 80 in the opposite direction
- positive
- positive
- positive
103 papers more in this group
See all 107 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.