Using The Plant Disorder Diagnostic Key
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Transcript of Using The Plant Disorder Diagnostic Key
Using The Plant Disorder Diagnostic Key
By Paul A. Thomas, and Bodie V. Pennisi Department of Horticulture,
College Of Agricultural and Environmental Sciences
High Heat, Low Fertility, High IrrigationHigh Light LevelsDry Winds
There’s Always More Than One Problem !
Unopened BudsTemperature
HumidityLight levelsNatural GasInsecticidesManganese
MitesThrips
Fully Opened FlowersTemperature
HumidityLight levelsInsecticidesNatural Gas
BotrytisVirus
Growing Meristem
BoronCalciumEthylene
Natural GasCyclamen mites
Thrips
New / Soft Growth
Trace ElementsNickel
CalciumLight Levels
Cyclamen mitesThrips
PropaneNatural GasHerbicides
Newly Matured Leaves
TemperatureHumidity
Light levelsPotassium
Phosphorus
Mature/Older Leaves
TemperatureHumidity
Light levelsSpacingNitrogen
PhosphorusMagnesiumPotassiumFluoride
Whole PlantDisorderTemperature
HumidityLight levels
SpacingNitrogenSoil pHSloil EC
Below Soil Disorder
TemperatureHumidity
Light LevelsDiseaseDroughtAnoxiaInsects
General Disorders
Using The Plant Diagnostic Key
A diagnostic key is a tool used to differentiatebetween many possible, yet similar looking symptoms.
Diagnostic keys are simple to use, and can significantlyspeed up the diagnosis process.
However, no key can replace actual diagnostic testing.Always test to verify assumptions before implementingany treatments.
Using The Diagnostic KeyThe diagnostician must first decide how to describe the problem.
Several descriptive words should be written down prior to reviewing the many choicesprovided in the key.
Using The Diagnostic Key
Cleared Tissue
Blackening
Dessicated
Wilted
Shiny
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
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 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.
Under each category, there are several choices to choose from.
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.
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.
These additional choices, marked B, and BB, allow us to further refine our choices, and focus in on the problem.
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 Fungicides, Herbicides yellow at the margins, few blooms, small flowers. 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. Herbicides / Sunscald
CCC. Entire plant or most leaves turn dark black-green, semi Surfactant / Soaps transparent to light, wilt, then die within 48 hours. Chlorine, Petroleum
fuels)
Next, we note thebest 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 Fungicides, Herbicides yellow at the margins, few blooms, small flowers. 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. Herbicides / Sunscald
CCC. Entire plant or most leaves turn dark black-green, semi Surfactant / Soaps transparent to light, wilt, then die within 48 hours. Chlorine, Petroleum fuels)
Next, we note thebest fit possibilitiesThat we should look into.
BB. Leaf color over a majority of the leaf surface is abnormal.
C. Entire plant pale green, poor growth with some marginal Fungicides, Herbicides yellow at the margins, few blooms, small flowers. Nutritional Deficiencies
(Also: Check roots for damage.)
CC. Entire plant or most leaves yellow, with central portions of the leaf affected. often dies within 3 to 10 days. Herbicides / Sunscald
CCC. Entire plant or many leaves turn dark black-green, semi Surfactant / Soaps, transparent to light, then die within 48 hours. Oils, Chlorine, Petroleum
Occasionally, the diagnosticianis directed to check additionalareas as many plant problemshave more than one cause.
Nutritional Disorders
http://www.montana.edu/wwwpb/pubs/mt4449.html#9
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An Excellent Publication!
Plant Nutrient Functions, Deficiency and
Toxicity Symptoms
Nitrogen
Entire plant light green or yellow.
No necrotic spotting or striping
Phosphorus
Purple or reddishdiscoloration.
Prominent on undersides.
Leaves slightly smaller, darker green.
Potassium
No interveinal chlorosis,
Chlorotic areas with burnt leaf margins, or spottong along leaf
CalciumYoung 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
BoronNew growth twisted, bunched up.
Leaves thicker, rolled or stiffened, brittle.
Meristem dies back
NickelMouse Ear or dwarf leaves.
Some darkening of the leaf.
Crinkled leaves.
IronSharp 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.
CopperYellow leaves.
Tips of leaves withered.
Leaf tipseventuallydie.
Chloride
No interveinal chlorosis,
Chlorotic and necrotic lesions with abrupt boundary between dead and living tissue
So how do we really know?
Soil AnalysisN as NH4
+ 20 or less (avoid above 40 ppm N as NO3
- 160 - 60 ppm
Element Parts per MillionP 30 - 5 ppm - lower is better!K 200 - 40 ppmCa 160 - 40 ppmMg 100 - 60 ppmS 75 - 100 ppm Fe 0.3 - 3.0 ppmMn 0.1 - 3.0 ppmZn 0.1 - 3.0 ppmCu 0.1 - 0.3 ppmB 0.05 - 0.5 ppm
Foliar AnalysisPercentage
N 2.72 - 6.28P 0.28 - 0.64K 1.88 - 3.48Zn 30 – 51Ca 0.93 - 1.13
Parts Per MillionCu 6 – 16Mg 0.32 - 0.78Mn 135 – 302Fe 72 – 277B 21 – 49S 0.22 - 0.50Mo 0.14 - 0.46Na 0.01 - 0.156Al 34 - 136
Fixing DeficienciesPost-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 NitrogenAffects Growth of Roots
20-20-20NO3 NH4
100 ppm
90oF
High Temperature Effect
Nutrient Management Self-Study CourseNutrient Management Self-Study CourseNutrient Management Self-Study CourseThank You !
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