Paper · 2025 · HortTechnology

Kaolin Clay Reduces Western Grape Leafhopper (Erythroneura elegantula Osborn) Abundance and Fruit Sunburn in Warm-climate Vineyards

Cody R. Copp

6
claims
13
verbatim quotes
2
citations
4
research areas
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Open access · cc-by-nc-nd

Abstract

Kaolin clay particle films offer multiple uses for managing pests and abiotic stress in horticultural cropping systems. Kaolin clay can specifically benefit wine grape production, but this potential is underexplored in the United States. This study addresses two issues for wine grape producers in the Columbia Basin: western grape leafhopper ( Erythroneura elegantula Osborn) populations and fruit sunburn damage. Two experiments were established in vineyards near Milton-Freewater, OR, USA: one in an organic Cabernet Sauvignon block with established leafhopper populations and another in blocks of Mourvèdre, Syrah, and Tempranillo. In the first experiment, kaolin was applied to whole canopies of Cabernet Sauvignon vines, and leafhopper populations were monitored weekly. Kaolin application reduced the peak abundance of second-generation leafhopper nymphs by 54% to 80%, although abundances were relatively low compared with other reports. Kaolin application did not influence Cabernet Sauvignon fruit quality. In the second experiment, west side basal leaves were removed and kaolin was applied to clusters before forecasted multiday extreme heat events (>100 °F). Clusters were rated for sunburn damage (i.e., berry shrivel, browning, and necrosis) following the heat events. The efficacy of kaolin varied by cultivar and year but generally reduced sunburn damage and improved the concentration of berry anthocyanins. While kaolin application did not eliminate sunburn damage, it proved an effective tool to reduce loss of usable fruit and improve quality of fruit exposed to both high temperature and light conditions. These experiments validate two important kaolin applications in vineyards under the warm climate conditions of the Columbia Basin region. As insect pest pressures and the frequency of extreme heat events increase, this technology is a critical tool for adapting perennial crops like grapes to a changing climate.

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Claims 6

Intervention effectobservedoriginal resultpositivemeasured

Claim · model-written summary

Kaolin reduced peak second generation leafhopper nymph abundance by 54% to 80%.

Taxon
Grapet0
Treatment
Kaolin applicatione0
Interactor
leafhoppere0pest
Outcome
peak abundance of second-generation leafhopper nymphse0
Direction
reducede0
Value
54% to 80%e0

Not reportedComparator

Verbatim

e0

“Kaolin application reduced the peak abundance of second-generation leafhopper nymphs by 54% to 80%”

✓ located verbatim in the source · abstract, characters 777–875 · show in text ↑
t0

“Grape”

✓ located verbatim in the source · title, characters 28–33 · show in text ↑
Intervention effectobservedoriginal resultno effectmeasured

Claim · model-written summary

Kaolin did not influence Cabernet Sauvignon fruit quality.

Taxon
Cabernet Sauvignone0
Treatment
Kaolin applicatione0
Outcome
fruit qualitye0
Direction
did not influencee0

Not reportedComparator

Verbatim

e0

“Kaolin application did not influence Cabernet Sauvignon fruit quality.”

✓ located verbatim in the source · abstract, characters 946–1016 · show in text ↑
Intervention effectobservedoriginal resultpositivemeasured

Claim · model-written summary

Kaolin generally reduced sunburn damage, with efficacy varying by cultivar and year.

Taxon
Grapet0
Treatment
kaoline0
Outcome
sunburn damagee0
Direction
reducede0
Qualifier
varied by cultivar and yeare0

Not reportedComparator

Verbatim

e0

“The efficacy of kaolin varied by cultivar and year but generally reduced sunburn damage”

✓ located verbatim in the source · abstract, characters 1284–1371 · show in text ↑
t0

“Grape”

✓ located verbatim in the source · title, characters 28–33 · show in text ↑
Intervention effectobservedoriginal resultpositivemeasured

Claim · model-written summary

Kaolin improved berry anthocyanin concentration.

Taxon
Grapet0
Treatment
kaoline1
Outcome
concentration of berry anthocyaninse0
Direction
improvede0

Not reportedComparator

Verbatim

e0

“improved the concentration of berry anthocyanins”

✓ located verbatim in the source · abstract, characters 1376–1424 · show in text ↑
t0

“Grape”

✓ located verbatim in the source · title, characters 28–33 · show in text ↑
e1

“The efficacy of kaolin varied by cultivar and year but generally reduced sunburn damage and improved the concentration of berry anthocyanins.”

✓ located verbatim in the source · abstract, characters 1284–1425 · show in text ↑
Intervention effectobservedoriginal resultpositivemeasured

Claim · model-written summary

Kaolin reduced loss of usable fruit.

Taxon
Grapet0
Treatment
kaolin applicatione1
Outcome
loss of usable fruite0
Direction
reducee0

Not reportedComparator

Verbatim

e0

“effective tool to reduce loss of usable fruit”

✓ located verbatim in the source · abstract, characters 1498–1543 · show in text ↑
e1

“While kaolin application did not eliminate sunburn damage, it proved an effective tool to reduce loss of usable fruit”

✓ located verbatim in the source · abstract, characters 1426–1543 · show in text ↑
t0

“Grape”

✓ located verbatim in the source · title, characters 28–33 · show in text ↑
Intervention effectobservedoriginal resultmixedmeasured

Claim · model-written summary

Kaolin did not eliminate sunburn damage.

Taxon
Grapet0
Treatment
kaolin applicatione0
Outcome
sunburn damagee0
Direction
did not eliminatee0

Not reportedComparator

Verbatim

e0

“kaolin application did not eliminate sunburn damage”

✓ located verbatim in the source · abstract, characters 1432–1483 · show in text ↑
t0

“Grape”

✓ located verbatim in the source · title, characters 28–33 · show in text ↑

kaolin · quality: phytochemicals · VitisResults differ

8 papers: 6 positive, 2 negative or no effect

5 papers in the same direction as this paper · 2 in the opposite direction

  1. no effect
  2. no effect
  3. positive

4 papers more in this group

See all 8 papers →

kaolin · pest · VitisResults agree

3 papers: 3 positive, 0 negative or no effect

2 papers in the same direction as this paper

  1. positive
  2. positive
See all 3 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.