Transcript Document
Using The Plant Disorder
Diagnostic Key
By Paul A. Thomas, and Bodie V. Pennisi
Department of Horticulture,
College Of Agricultural and Environmental Sciences
There’s Always More
Than One Problem !
High Heat,
Low Fertility,
High Irrigation
High Light Levels
Dry Winds
Unopened Buds
Temperature
Humidity
Light levels
Natural Gas
Insecticides
Manganese
Mites
Thrips
Fully Opened
Flowers
Temperature
Humidity
Light levels
Insecticides
Natural Gas
Botrytis
Virus
Growing
Meristem
Boron
Calcium
Ethylene
Natural Gas
Cyclamen mites
Thrips
New / Soft
Growth
Trace Elements
Nickel
Calcium
Light Levels
Cyclamen mites
Thrips
Propane
Natural Gas
Herbicides
Newly Matured
Leaves
Temperature
Humidity
Light levels
Potassium
Phosphorus
Mature/Older
Leaves
Temperature
Humidity
Light levels
Spacing
Nitrogen
Phosphorus
Magnesium
Potassium
Fluoride
Whole Plant
Disorder
Temperature
Humidity
Light levels
Spacing
Nitrogen
Soil pH
Sloil EC
Below Soil
Disorder
Temperature
Humidity
Light Levels
Disease
Drought
Anoxia
Insects
General Disorders
Using The Plant
Diagnostic Key
A diagnostic key is a tool used to differentiate
between many possible, yet similar looking symptoms.
Diagnostic keys are simple to use, and can significantly
speed up the diagnosis process.
However, no key can replace actual diagnostic testing.
Always test to verify assumptions before implementing
any treatments.
Using The Diagnostic Key
The diagnostician must
first decide how to
describe the problem.
Several descriptive
words should be written
down prior to reviewing
the many choices
provided in the key.
Using The Diagnostic Key
Cleared Tissue
Blackening
Dessicated
Wilted
Shiny
There are several categories or
approaches to choose from,
depending on the extent of the
problem, or the plant parts
that are expressing symptoms
of a disorder.
Problems Involving ENTIRE Crop With or Without Pattern
Problems Involving WHOLE PLANT With Normal Shape Leaves And Stems.
Problems That Appear To Primarily Involving LEAVES, Secondarily Flowers
Problems Involving FLOWERS
Problems Involving ROOT SYSTEMS
Under each category, there are
several choices to choose from.
Problems That Appear to Primarily Involve LEAVES and to a Lesser Extent,
Flowers.
A.
LEAF SHAPE ABNORMAL, twisted, or physically damaged stems, internodes normal.
AA .
LEAF SHAPE NORMAL, internode length normal, but leaves off-color, cleared or have spots.
AAA
LEAF SHAPE NORMAL, however, stem internodes are very long or very short.
AAAA
Leaf shape normal, stem internodes normal. Stems severed / broken at soil line.
AAAAA.
Leaf puckered or with expanded cells, galls, thickening of epidermis.
The three sub-choices are marked A, AA , and AAA as they are all related
to the category, however, they denote different possibilities from which we
may decide on the best fit to our described symptoms. Underneath “AA” are the next
level of choices.
These additional choices, marked B,
and BB, allow us to further refine
our choices, and focus in on the problem.
AA . LEAF SHAPE NORMAL, internode length normal, but leaves off-color, cleared or
have spots.
B.
Leaf color in a small portion of the leaf is abnormal.
BB. Leaf color over a majority of the leaf surface is abnormal.
Next, we note the
best fit sub-category.
AA . Leaves appear normal shape, discrete parts of plant are off-color, cleared or wilted.
BB. Leaf color over a majority of the leaf surface is abnormal.
C.
Entire plant pale green, poor growth with some marginal
yellow at the margins, few blooms, small flowers.
Fungicides, Herbicides
Nutritional Deficiencies
(Check roots for damage.)
CC.
Entire plant or most leaves yellow, with central portions
of the leaf strongly affected. Tissue dies within 3 to 10 days.
CCC. Entire plant or most leaves turn dark black-green, semi
transparent to light, wilt, then die within 48 hours.
Herbicides / Sunscald
Surfactant / Soaps
Chlorine, Petroleum
fuels)
Next, we note the
best fit possibilities
That we should look into.
AA . Leaves appear normal shape, discrete parts of plant are off-color, cleared or wilted.
BB. Leaf color over a majority of the leaf surface is abnormal.
C.
Entire plant pale green, poor growth with some marginal
yellow at the margins, few blooms, small flowers.
Fungicides, Herbicides
Nutritional Deficiencies
(Check roots for damage.)
CC.
CCC.
Entire plant or most leaves yellow, with central portions
of the leaf strongly affected. Tissue dies within 3 to 10 days.
Herbicides / Sunscald
Entire plant or most leaves turn dark black-green, semi
transparent to light, wilt, then die within 48 hours.
Surfactant / Soaps
Chlorine, Petroleum fuels)
Occasionally, the diagnostician
is directed to check additional
areas as many plant problems
have more than one cause.
BB. Leaf color over a majority of the leaf surface is abnormal.
C.
Entire plant pale green, poor growth with some marginal
yellow at the margins, few blooms, small flowers.
Fungicides, Herbicides
Nutritional Deficiencies
(Also: Check roots for damage.)
CC.
CCC.
Entire plant or most leaves yellow, with central portions
of the leaf affected. often dies within 3 to 10 days.
Herbicides / Sunscald
Entire plant or many leaves turn dark black-green, semi
transparent to light, then die within 48 hours.
Surfactant / Soaps,
Oils, Chlorine, Petroleum
Nutritional Disorders
Plant Nutrient Functions,
Deficiency and
Nutrient Management Self-Study Course
Toxicity Symptoms
http://www.montana.edu/wwwpb/pubs/mt4449.html#9
An Excellent Publication!
Nitrogen
Entire plant light
green or yellow.
No necrotic
spotting or striping
Phosphorus
Purple or reddish
discoloration.
Prominent on
undersides.
Leaves slightly
smaller, darker green.
Potassium
No interveinal
chlorosis,
Chlorotic areas
with burnt leaf
margins, or
spottong along leaf
Calcium
Young leaves
increasingly
smaller,
bunched,
hooked may
turn brown and
die back.
Buds may or
may not be
affected
Magnesium
General chlorosis with
interveinal chlorosis
Leaves sometimes
have red, yellow or
necrotic spots.
Sulfur
Young leaves light
green.
No chlorotic
spotting or striping
Boron
New growth twisted,
bunched up.
Leaves thicker, rolled
or stiffened, brittle.
Meristem dies back
Nickel
Mouse Ear
or dwarf leaves.
Some darkening
of the leaf.
Crinkled leaves.
Iron
Sharp interveinal
chlorosis.
Leaves full size.
Manganese
Interveinal chlorosis.
Stunted growth.
Necrotic spots.
Molybdenum
Pale, light green
leaves
Leaves scorched,
rolled or twisted
Zinc
Middle leaves
with interveinal
chlorosis.
Copper
Yellow leaves.
Tips of leaves withered.
Leaf tips
eventually
die.
Chloride
No interveinal chlorosis,
Chlorotic and necrotic
lesions with abrupt
boundary between dead
and living tissue
So how do we really know?
Soil Analysis
N as NH4+
N as NO3-
20 or less (avoid above 40 ppm
160 - 60 ppm
Element
Parts per Million
P
K
Ca
Mg
S
Fe
Mn
Zn
Cu
B
30 - 5 ppm
- lower is better!
200 - 40 ppm
160 - 40 ppm
100 - 60 ppm
75 - 100 ppm
0.3 - 3.0 ppm
0.1 - 3.0 ppm
0.1 - 3.0 ppm
0.1 - 0.3 ppm
0.05 - 0.5 ppm
Foliar Analysis
N
P
K
Zn
Ca
Cu
Mg
Mn
Fe
B
S
Mo
Na
Al
Percentage
2.72 - 6.28
0.28 - 0.64
1.88 - 3.48
30 – 51
0.93 - 1.13
Parts Per Million
6 – 16
0.32 - 0.78
135 – 302
72 – 277
21 – 49
0.22 - 0.50
0.14 - 0.46
0.01 - 0.156
34 - 136
Fixing Deficiencies
Post-planting amendments for common
deficiencies:
Material
Rate
( Oz / 100 gal of water)
Magnesium sulfate
32 oz.
Every 3 weeks
Calcium nitrate
32 oz.
Every 3 weeks
Iron sulfate*
1.0 oz.
1 application *
*Excess can cause leaf spotting and problems
Form Of Nitrogen
Affects Growth of Roots
NO3
20-20-20
NH4
High Temperature Effect
100 ppm
90oF
Thank You !
Nutrient Management Self-Study Course
Lets Take A Test !
2,4-D on Salvia
• 3 d after exposure
• 11 d after exposure
2,4-D on Salvia
• 3 d after exposure
• 11 d after exposure
2,4-D on Salvia
• 3 d after exposure
• 11 d after exposure
Excess Ammonia Nitrogen
Mottle Pansy Syndrome
Some Examples