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Chlorosis
Joan R. DavenportWSU-Prosser
It is a bad chlorosis year
๏ Cool wet springs
Why?
More about Chlorosis
๏ “Stationary” in vineyard
Stationary Nature
More about Chlorosis
๏ “Stationary” in vineyard๏ Expands within a zone๏ Year dependent๏ By the time you see it, it is too late
More about Chlorosis
๏ Soil pH and free ｀lime’ (calcium carbonate)๏ Testing leaves for micronutrients
๏ ｀Bioactive’iron
Research
Stevens et al
๏ NpHuric๏ FeEDTA
Davenport et al
๏ Vivianite soil injection (not shown)
๏ FeEDDHA๏ Biostimulants
A Word About Chelates
FeEDDHA Trials
๏ Applied to soils ๏ Dissolved liquid๏ Divided into 3 applications๏ May, June, July๏ Lower rates years 1 & 2๏ Higher rates year 3
Rates Years 1 & 2Treatment g/vine oz/vine lbs/A
Control
Low
Medium
High
Very High
0 0 0
10 0.35 16
20 0.70 32
30 1.05 48
40 1.40 64
Ranking3 & 4
0 - none, 1 = up close only, 2 = more extensive, 5 = white/dead
Chlorosis Results
Treatment Average Min Max
Control
Low
Medium
High
Very High
2.90 2.50 4.00
1.35 0.75 2.00
1.05 0.75 1.25
1.20 1.00 1.50
1.40 1.00 2.00
Chlorosis Yrs 1 & 2
๏ No yield differences๏ Year 2 lower chlorosis in High & Very High๏ New treatments for year 3
Rates Year 3Treatment g/vine oz/vine lbs/A
Control
High
Very High
2 X High
2 X Very High
0 0 0
30 1.05 48
40 1.40 64
60 2.10 96
80 2.80 128
Chlorosis Results
Treatment Average Min Max
Control
High
Very High
2 X High
2 X Very High
2.80 1.50 4.00
1.50 1.00 3.00
0.60 0.50 1.00
1.20 0.50 1.50
1.10 0.50 2.00
Chlorosis Year 3
๏ No yield differences๏ The very high rate as good as anything higher๏ 64 lbs/A FeEDDHA๏ Spot treatment?๏ Price (estimated cost $4000-$6000/T +
application)
Biostimulants
Material 3-4 Leaf Post-Bloom Both
Water
Apex 10
Reclaim
Renew
Control Control Control
E L B
E L B
E L B
Biostimulants
Material 3-4 Leaf Post-Bloom Both
Water
Apex 10
Reclaim
Renew
Control Control Control
E L B
E L B
E L B
Chlorosis rated on each plant in plot, both sides
Yield
Year 1
Year 1
Year 2
Year 2
Biostimulants
๏ No yield differences๏ First year promising๏ Second year not๏ Frequency, rates, economics
What Should I Do?
๏Chelated iron (FeEDDHA)๏64 lbs/A๏Split application (32 spring, 32 bloom)
๏Liquid to ground๏Map for zonal application
Questions?
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