upper leaf necrosis in oriental hybrid lilies william b. miller and y.-c. (alex) chang department of...
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Upper Leaf Necrosis in Upper Leaf Necrosis in Oriental Hybrid LiliesOriental Hybrid Lilies
William B. Miller and Y.-C. (Alex) ChangWilliam B. Miller and Y.-C. (Alex) ChangDepartment of HorticultureDepartment of Horticulture
Cornell UniversityCornell University
..
How do ULN symptoms develop?
1st day symptoms visible
21 days later
28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 460
5
10
15
20
25
Days after planting
Crop 1, 91 necrosed plants
Crop 2, 85 necrosed plants
Crop 3, 83 necrosed plants
When does ULN occur?
Most plants begin to show symptoms 30-40 days after planting
% N
ecro
sed
Pla
nts
Where do ULN symptoms occur?
ULN only occurs on leaves associated with flower buds and the leaves immediately below the buds
Macronutrients (%)
P K Ca Mg
Healthy 0.31 b 2.33 b 0.57 a 0.19 a
Necrosed 0.44 a 3.36 a 0.10 b 0.16 b
Micronutrients (ppm)
Fe Mn Cu B Zn Mo Ni
Healthy 98.4 a 32.6 a 6.04 a 26.8 a 55.4 b 0.12 a 1.23 a
Necrosed 62.2 a 22.1 b 2.67 b 22.1 a 70.7 a 0.17 a 0.63 a
Tissue analysis Tissue taken at this ULN stage
1 23
45
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0 1 2 3 4 5
Necrosis Index
The hypothesized cause of ULNThe hypothesized cause of ULN
ULN is a calcium deficiency disorder: Leaf overlap reduces
transpiration, thereby reducing Ca transport to the young leaves, thereby encouraging the symptoms
Also due to insufficient Ca supply from the bulb
CalciumCalcium
Calcium moves upward in plants with the water flowCalcium moves upward in plants with the water flow Xylem (water-conducting) systemXylem (water-conducting) system Calcium accumulates in leaves that are actively losing water Calcium accumulates in leaves that are actively losing water
through transpirationthrough transpiration Young or “congested” leaves don’t transpire as muchYoung or “congested” leaves don’t transpire as much Leaves (or fruit) that grow faster than their calcium supply are Leaves (or fruit) that grow faster than their calcium supply are
susceptible to calcium deficiency problems (e.g. blossom end susceptible to calcium deficiency problems (e.g. blossom end rot in tomato)rot in tomato)
Bulb Scales
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
0.2
0
2
4
6
8
10
12
14
16
18
0
2
4
6
8
10
12
14
16
18
0 10 20 30 40 50 60 70
Days after planting
0
0.5
1
1.5
2
2.5
3
0
20
40
60
80
100
120
140
160
0
1
2
3
4
5
6
0 10 20 30 40 50 60 70
Days after planting
All Leaves
Folded (young) Leaves
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0 10 20 30 40 50 60 70
Days after planting
Table . Effect of fertilizer calcium levels on upper leafnecrosis on Lilium cv. Star Gazer. n=16.
Calciumlevel(mM)
Necrosis
Incidence (%) Severity
Flower budabortion
(%)
4 (control) 12.5 z 0.1 cy 0 z
0.2 75.0** 4.1 b 0NS
0.0 100.0** 40.9 a 100**
0 mM Ca 0.2 mM Ca 4 mM Ca
Sand cultures…14/16 cm bulbsSand cultures…14/16 cm bulbs
Ca-free nutrient solution reproduced ULN symptoms
0 1.2
53.3
0
10
20
30
40
50
60
12/14 cm 14/16 cm 16/18 cm
Bulb size
Nec
rose
d p
lan
ts (
%)
Larger bulb sizes increase ULN
12/14 cm 16/18 cm14/16 cm
Bulb size vs. leaf enclosure (“apical congestion”)
Artificial Leaf UnfoldingArtificial Leaf Unfolding
Table . Effect of artificial unfolding on reducingupper leaf necrosis on Lilium cv. Star Gazer.n=30.
Unfolding frequency(times/day)
Necrosis
Incidence (%) Severity
Control 86.7z 15.1ay
1 3.3** 0.47 b
2 0.0** 0.00 b
Artificial Leaf UnfoldingArtificial Leaf Unfolding
1X/dayControl 2X/day
Overhead fans to blowing down
Overhead fans to reduce ULN
Fan off Fan-low Fan-high
Adding calcium to bulbs before plantingAdding calcium to bulbs before planting
A range of studies, using several Ca concentrations and A range of studies, using several Ca concentrations and dipping times (1 min to 16 hours) were conducteddipping times (1 min to 16 hours) were conducted
Basic conclusion: no positive effectBasic conclusion: no positive effect
NecrosisCalciumchloride
concentration(mM)
Dippingtime
(hour)Incidence
(%)Severity
Lethalcalciumdamage
(%)
0 16 92.9 12.8 0.0200 1 92.9 12.3 0.0200 4 100.0 14.2 3.6200 16 81.5 12.3 0.0400 1 92.9 13.2 0.0400 4 85.2 14.0 3.6400 16 84.0 12.7 10.7
Effectiveness of bulb dips in calcium chloride on upper leaf necrosis on Lilium cv. Star Gazer.
Upper Leaf Necrosis is a calcium deficiency disorder:Upper Leaf Necrosis is a calcium deficiency disorder: Insufficient Ca supply from the bulbInsufficient Ca supply from the bulb
Insufficient transpiration resulting from leaf enclosure of the Insufficient transpiration resulting from leaf enclosure of the
shoot apexshoot apex
Necrosis symptoms begin to show 30-40 days after plantingNecrosis symptoms begin to show 30-40 days after planting
This is when plants are about 12” tall This is when plants are about 12” tall
The 5 leaves immediately below the flower buds and the leaves The 5 leaves immediately below the flower buds and the leaves
associated with the buds are most susceptibleassociated with the buds are most susceptible to ULN to ULN
Actual injury occurs much earlier than symptom Actual injury occurs much earlier than symptom
expressionexpression
Conclusions
Factors that increase ULN:Factors that increase ULN: Larger bulbsLarger bulbs Low transpirationLow transpiration
High humidity (mist)High humidity (mist)
Horticultural methods to reduce ULN:Horticultural methods to reduce ULN: Use smaller bulbs if applicableUse smaller bulbs if applicable
Keep greenhouse “dry”Keep greenhouse “dry”
Prevent water accumulation on leavesPrevent water accumulation on leaves
Supplemental lighting in winterSupplemental lighting in winter
Daily foliar Ca sprays (days 25-45)Daily foliar Ca sprays (days 25-45)
Bulb dips are not promisingBulb dips are not promising
Airflow! Overhead fans offer a promising method to control ULNAirflow! Overhead fans offer a promising method to control ULN
Conclusions
Acknowledgements Acknowledgements
USDA/ARS-SAF National Floriculture Research USDA/ARS-SAF National Floriculture Research Initiative Initiative
Fred C. Gloeckner Foundation Fred C. Gloeckner Foundation Royal Dutch Wholesalers Association for Flowerbulbs Royal Dutch Wholesalers Association for Flowerbulbs
and Nursery Stock and Nursery Stock Post/Schenkel Memorial CouncilPost/Schenkel Memorial Council Ministry of Education, TaiwanMinistry of Education, Taiwan