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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 Irrigation High Light Levels Dry Winds. There’s Always More Than One Problem !. Unopened Buds.

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Using The Plant Disorder Diagnostic Key

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  1. Using The Plant Disorder Diagnostic Key By Paul A. Thomas, and Bodie V. Pennisi Department of Horticulture, College Of Agricultural and Environmental Sciences

  2. High Heat, Low Fertility, High IrrigationHigh Light LevelsDry Winds There’s Always More Than One Problem !

  3. Unopened Buds Temperature Humidity Light levels Natural Gas Insecticides Manganese Mites Thrips

  4. Fully Opened Flowers Temperature Humidity Light levels Insecticides Natural Gas Botrytis Virus

  5. Growing Meristem Boron Calcium Ethylene Natural Gas Cyclamen mites Thrips

  6. New / Soft Growth Trace Elements Nickel Calcium Light Levels Cyclamen mites Thrips Propane Natural Gas Herbicides

  7. Newly Matured Leaves Temperature Humidity Light levels Potassium Phosphorus

  8. Mature/Older Leaves Temperature Humidity Light levels Spacing Nitrogen Phosphorus Magnesium Potassium Fluoride

  9. Whole Plant Disorder Temperature Humidity Light levels Spacing Nitrogen Soil pH Sloil EC

  10. Below Soil Disorder Temperature Humidity Light Levels Disease Drought Anoxia Insects

  11. General Disorders

  12. 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.

  13. 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.

  14. Using The Diagnostic Key Cleared Tissue Blackening Dessicated Wilted Shiny

  15. 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

  16. 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.

  17. 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.

  18. 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 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 / SunscaldCCC. Entire plant or most leaves turn dark black-green, semi Surfactant / Soaps transparent to light, wilt, then die within 48 hours. Chlorine, Petroleum fuels)

  19. 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 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)

  20. 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 / SunscaldCCC. 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 diagnostician is directed to check additional areas as many plant problems have more than one cause.

  21. Nutritional Disorders

  22. Plant Nutrient Functions, Deficiency and Toxicity Symptoms Nutrient Management Self-Study Course Nutrient Management Self-Study Course Nutrient Management Self-Study Course http://www.montana.edu/wwwpb/pubs/mt4449.html#9 An Excellent Publication!

  23. Nitrogen Entire plant light green or yellow. No necrotic spotting or striping

  24. Phosphorus Purple or reddish discoloration. Prominent on undersides. Leaves slightly smaller, darker green.

  25. Potassium No interveinal chlorosis, Chlorotic areas with burnt leaf margins, or spottong along leaf

  26. Calcium Young leaves increasingly smaller, bunched, hooked may turn brown and die back. Buds may or may not be affected

  27. Magnesium General chlorosis with interveinal chlorosis Leaves sometimes have red, yellow or necrotic spots.

  28. Sulfur Young leaves light green. No chlorotic spotting or striping

  29. Boron New growth twisted, bunched up. Leaves thicker, rolled or stiffened, brittle. Meristem dies back

  30. Nickel Mouse Ear or dwarf leaves. Some darkening of the leaf. Crinkled leaves.

  31. Iron Sharp interveinal chlorosis. Leaves full size.

  32. Manganese Interveinal chlorosis. Stunted growth. Necrotic spots.

  33. Molybdenum Pale, light green leaves Leaves scorched, rolled or twisted

  34. Zinc Middle leaves with interveinal chlorosis.

  35. Copper Yellow leaves. Tips of leaves withered. Leaf tips eventually die.

  36. Chloride No interveinal chlorosis, Chlorotic and necrotic lesions with abrupt boundary between dead and living tissue

  37. So how do we really know?

  38. Soil Analysis N as NH4+ 20 or less (avoid above 40 ppm N as NO3- 160 - 60 ppm Element Parts per Million P 30 - 5 ppm - lower is better! K 200 - 40 ppm Ca 160 - 40 ppm Mg 100 - 60 ppm S 75 - 100 ppm Fe 0.3 - 3.0 ppm Mn 0.1 - 3.0 ppm Zn 0.1 - 3.0 ppm Cu 0.1 - 0.3 ppm B 0.05 - 0.5 ppm

  39. Foliar Analysis Percentage N 2.72 - 6.28 P 0.28 - 0.64 K 1.88 - 3.48 Zn 30 – 51 Ca 0.93 - 1.13 Parts Per Million Cu 6 – 16 Mg 0.32 - 0.78 Mn 135 – 302 Fe 72 – 277 B 21 – 49 S 0.22 - 0.50 Mo 0.14 - 0.46 Na 0.01 - 0.156 Al 34 - 136

  40. 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

  41. Form Of Nitrogen Affects Growth of Roots 20-20-20 NO3 NH4

  42. High Temperature Effect 100 ppm 90oF

  43. Thank You ! Nutrient Management Self-Study Course Nutrient Management Self-Study Course Nutrient Management Self-Study Course

  44. Lets Take A Test !

  45. 2,4-D on Salvia • 3 d after exposure • 11 d after exposure

  46. 2,4-D on Salvia • 3 d after exposure • 11 d after exposure

  47. 2,4-D on Salvia • 3 d after exposure • 11 d after exposure

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