Effects of Kaolin Clay (Surround
WP) On Blueberry Plants
James D. Spiers, Frank B.
Matta, Blair Sampson, John B.
Braswell, Donna S. Marshall
Surround WP

Demonstrated consistent control or suppression
of almost all the major and minor apple insect
pests.
 The Organic Materials Review Institute officially
recognized Surround as “organic” in 2000.
 Surround actually increases net photosynthesis,
and can provide secondary benefits to the trees’
overall health.
 Keeps the tree cool so that photosynthesis can
continue longer into the afternoon on hot days,
after untreated trees have already shut down
because of heat stress.
Surround WP continued.

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Surround WP is a wettable
powder which leaves a
white, protective, powdery
film on the surfaces of
leaves, stems, and fruit.
Deters insects in several
ways.
Tiny particles attach to
insects, agitating and
repelling them.
Insects find the plant
unrecognizable as a host.
Thrips (Frankliniella spp.)

Hide within parts of flowers not easily
penetrated by insecticides.
 Excessive feeding on floral buds, open
flowers, or developing fruit can reduce
yield by inducing premature fruit abortion.
 Color alone may attract some thrips
species, but if UV reflectance is high, then
anthophilous thrips are repelled from the
surface of attractive colors.
Project Goals

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
Determine effects of Surround WP on insect
control (thrips) of rabbiteye blueberry plants.
Determine the effects of kaolin on fruit set,
development, and berry size when applied to
southern highbush blueberry plants during early
flower stages.
Determine effects of kaolin on blueberry yield,
quality, and plant growth.
Determine the stage of development when kaolin
clay could be the most beneficial to blueberry
plants.
Study 1 - Effect of Surround WP
on thrips population.
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Three rabbiteye blueberry cultivars (‘Delite’, ‘Tifblue’, and
‘Woodard’) were arranged in a Latin square design.
Treatments consisted of sprayed and unsprayed plants.
Sprayed plants were sprayed with Surround WP on 3
occasions: during bloom (March 7, 2001), post-bloom (April
20), and pre-harvest (May 17).
Sticky traps were placed on the center plant in the middle of
the canopy on the day of application.
Traps were collected exactly 1 week following application.
The number of thrips per trap was counted.
Yield was collected and recorded from each plant that
contained a sticky trap.
Data was analyzed by ANOVA using SAS (1996).
Average number of thrips/trap
during bloom stage.
Kaolin
Thrips per trap
Unsprayed
250
212
200
153
150
100
128
87
103
98
50
0
'Delite'
'Tifblue' 'Woodard'
Average number of thrips/trap
during post-bloom stage.
Thrips per trap
Kaolin
Unsprayed
1000
900
800
700
600
500
400
300
200
100
0
821
449
235
127
'Delite'
154
211
'Tifblue' 'Woodard'
Average number of thrips/trap
during pre-harvest stage.
Kaolin
Thrips per trap
Unsprayed
3000
2500
2329
2000
1500
1000
619
164 280
500
0
789
'Delite'
105
Tifblue' 'Woodard'
Effects of thrip control on yield
Yield (kg/bush)
15
10.46
11.54
10.72 10.44
10
5.47
5
2.73
0
'Delite'
'Tifblue'
'Woodard'
Results
The number of thrips per trap was
significantly reduced by the
application of Surround WP.
 The differences in yield (kg/bush)
was not significant for sprayed and
unsprayed plants.
 Application of Surround WP did not
affect pollination.

Study 2. Effects of Surround WP
on bloom stage.

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Southern highbush blueberry plants (‘Cooper’) were
arranged in a random complete block design consisting of
9 replications of 2 plants per replication.
Treatments consisted of 1 application of Surround WP and
no spray.
Ten buds from each plant were rated according to the
flower bud rating scale (1-7) with the goal of getting two of
each rating 3-7 on each plant.
Flower buds were rated 10 days following application and
the number of flowers per bud was recorded.
Fruit diameter was measured and the number of fruit per
bud was recorded on 3 occasions.
Data was analyzed by ANOVA using SAS (1996).
Flower Bud Development Stages
Effects of Surround WP on Fruit
set and Development
Results

The rate of development for the blooms
sprayed with Surround WP was slower.
 The size of the fruit was smaller for the
plants sprayed with Surround WP.
 The number of flowers/bud, berries
present, and fruit picked was greater on
the plants sprayed with Surround WP.
Study 3. Effects of time of application of
Surround WP on ‘Magnolia’ blueberry
plants.
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Four replications consisting of 3 plants per experimental
block.
The initial volume of the plant size was obtained prior to
treatment.
Treatments: pre-fruit (approx. 50% flowering), early fruit set,
mid-maturity, approx. 2 weeks prior to harvest, and a
control group which was not sprayed.
Fruit was harvested from the middle plant in each block
when ripe and yield was measured. Harvesting dates were
May 14, May 23, May 31, and June 7, 2001.
On each harvesting date the berries were measured for
chemical analysis, compression, and turbidity (residue).
Final volume of plant size was measured and growth was
calculated.
Effects of application time of
Surround on fruit characteristics
Average Yield for ‘Magnolia’
Blueberry Plants
Av e rage Y ie ld (g )
1400
1120.2
1200
1000
800
738.2
693.7
653.4
624
MM
Pre-harv
600
400
200
0
Contr ol
Pre-F
EFS
Average volume (in.³) of growth
for ‘Magnolia’ blueberry plants.
Growth (inches)
0.4
0.33
0.3
0.23
0.2
0.1
0.2
0.18
0.05
0
Control Pre-fruit
EFS
MM Pre-harv
Results

SS, TS, pH, and compression results were
the same for each treatment.
 Residue was the same for control and prefruit treatments.
 The yield was greatest when applied
before fruiting.
 Surround WP increased growth of
‘Magnolia’. The earlier Surround WP was
applied to the plants the more growth was
promoted.
Conclusion

Surround WP can be used effectively to
control thrips populations without
affecting pollination.
 Surround WP can be used to enhance fruit
set.
 Application of Surround WP before fruit
set can increase yields without leaving
significant residue on fruit.
 Application of Surround WP can promote
growth of blueberry plants.