2013 Advanced Master Gardener Training Program: Become a Plant Problem Sleuth


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  • Maple, elm, ash, chestnut, and poplar
  • Interveinal necrosis due to herbicide toxicity or to severe manganese deficiency.
  • Pin oak and silver maple are particularly susceptible.
  • Viruses cannot be controlled with pesticides – cannot survive outside of their host, so control is by prevention of their spread.
  • Salt burn on strawberry – client used fresh horse manure on his plants
  • Leaves do not abscise – look for ooze on affected tissues (usually only leaves). Susceptible trees include rose family –especially crabapple, pear, and serviceberry. Avoid over-fertilization. Usually treated with copper sprays to prevent spread (not an eradicant). Also use Streptomycin.
  • Leaves do not abscise – look for ooze on affected tissues (usually only leaves). Susceptible trees include rose family –especially crabapple, pear, and serviceberry. Avoid over-fertilization. Usually treated with copper sprays to prevent spread (not an eradicant). Also use Streptomycin.
  • Left-cytospora canker; right-sunscald
  • 2013 Advanced Master Gardener Training Program: Become a Plant Problem Sleuth

    1. 1. BECOME A PLANTPROBLEM SLEUTHMaster Gardener Advanced Training ProgramMay 30, 2013Heidi Kratsch, University of Nevada CooperativeExtension
    2. 2. LEARNING OBJECTIVESRecognize common plantproblems seen in northernNevada.Learn to use our digital stereomicroscope
    3. 3. C.L.U.E.S.
    4. 4. COLLECT INFORMATION Identify species/cultivar How long have you noticed symptoms? Sun/wind exposure? Recent disturbances? Soil texture (if known)? Watering schedule? Chemicals used?
    6. 6. RECOGNIZE WHAT’SNORMALAcer negundo ‘Flamingo’Variegated juniper
    7. 7. LOOK FOR PATTERNS Sudden or gradual appearance of symptoms? Many plant species affected or only one? Symptoms on one side or area of the plant… orall over the plant?
    8. 8. WILTING (COLLAPSE OFTISSUES)Causes: Under-watering Over-watering Root loss High soil salinity Insects feeding on theconducting tissuesCaused by boring insectCaused by water stress
    9. 9. LEAF NECROSIS (DEATH)Causes: Lack of water Too much sun Frozen soil Drying winds Herbicide toxicity Look for patternsWinter burn on Creeping Oregon Grape
    10. 10. LOOK FOR PATTERNS OFLEAF NECROSIS Note the pattern ofnecrosis on the entireplant.Interveinal necrosisLeaf blotch Marginal necrosis
    11. 11. LEAF CHLOROSIS(YELLOWING) Nutrient deficiency Disease or insects Mechanical damageInterveinal chlorosiscaused by lack of iron.Often a problem inalkaline soils.General chlorosiscaused by nitrogendeficiency
    12. 12. LEAF CHLOROSISRose mosaic virusStippling caused byleafhopper Variegated cultivar of spotted laurelPotassium deficiency
    13. 13. WHAT IS THIS?
    14. 14. BIOTIC VS. ABIOTICPROBLEMSBiotic (caused byliving things) Physical evidence Spreads progressivelythroughout a plant Limited to plants of aparticular species orfamilyAbiotic (caused byenvironmentalstress) No physical evidence May or may notdevelop progressivelythroughout a plant May affect many or allplants in a landscape Affects only the partof the landscapeaffected by the stress
    15. 15. EVIDENCE OF INSECTDAMAGE:Chewed leaves Caterpillars, beetles,sawflies, leaf minersBleached, yellowed, orstippled leavesLeafhoppers, aphids,thrips, mitesDistortion of plant part Thrips, aphidsDieback of twigs/branches Borers, scalesPresence of excrement ordewAphids, whiteflies, thrips
    16. 16. WHAT DO YOU SEE?
    17. 17. BIOTIC OR ABIOTIC?
    18. 18. HOW IS THIS DIFFERENT?Dothistroma Needle BlightAustrian, ponderosa and mugo pines aresusceptible under the right conditions
    19. 19. BIOTIC OR ABIOTIC?Phosphorus deficiencyCaused by planting when soils are too cold
    20. 20. BIOTIC OR ABIOTIC?Marsonnina leaf spot
    21. 21. GUMMING (SAP FLOW) Common stress symptom onPrunus and Pinus sp. Caused by waterdeficit or mechanical injury. If accompanied by foaming orfoul odor, may be biotic(bacterial or fungal).
    22. 22. BIOTIC OR ABIOTIC?
    23. 23. BIOTIC OR ABIOTIC? Bacterial – occurs onplants in the Rosefamily Twigs curl to form a“shepherd’s crook” Conditions:Temperaturesbetween 65 F and 86F and relativehumidity above 65%
    24. 24. FIREBLIGHT?
    25. 25. BIOTIC OR ABIOTIC?Cytospora canker
    26. 26. WHICH IS BIOTIC?
    28. 28. USE REFERENCES www.extension.org www.google.com (look for sites with .edu or .gov) Pests of Landscape Trees and Shrubs, UC-Davis Abiotic Disorders of Landscape Plants, UC-Davis Weeds of the West, U of Wyoming Weeds of California and Other Western States,Volumes 1 &2, UC-Davis Garden Insects, Cranshaw Pest ID cards
    29. 29. MOST PROBLEMS STARTOUT AS WEATHER ORCULTURAL ISSUES.Eliminate the mostobvious causes first: Improper watering(cultural) Winter damage Alkaline and/or salty soil Southern or westernexposure Heavy, clay soils – poordrainage Herbicide damage Insects and diseaseare often asecondary problem.
    30. 30. STATE YOUR TENTATIVEDIAGNOSIS Rarely can say with absolute certainty. Often a choice among a few options. Offer the most reasonable and commondiagnosis. Provide a safe solution – and an alternatestrategy if that doesn’t resolve the problem. Let them know they can call again if theirproblem is not resolved.
    31. 31. C.L.U.E.S.
    33. 33. WHAT IS LIGHTMICROSCOPY? Light passes through or falls on a sample. Lenses focus that light (and the image of thesample that the light carries). The sample seems to be brought nearer our eyesfor our careful examination.
    34. 34. WHAT IS A STEREOMICROSCOPE? Uses two optical pathways (two eyepieces) Provides slightly different viewing angles to theleft and right eyes Produces a 3-dimensional image We have a 4-D microscope! You can focus and show your clients in real time. And you can take a picture and save to a file or print.
    35. 35. THE PARTS OF THEMICROSCOPEStageFocus knobZoom magnification adjustment (8x – 35x)Eyepieces(oculars10x)On/off switch on backCarrying handleLight source(below)Light sourcesIndicator light/button for computer connectionGreen = connectedOrange = not connectedIlumination direction/brightness controlsIntegrated 3.0 megapixel CMOS camera
    36. 36. ADJUST THE OCULARS TO FIT THESPACING OF YOUR EYES When the oculars aretoo far apart, you willsee the sample as twoimages.Bring the ocularstogether until you seeonly one image.
    37. 37. MAGNIFICATION Magnification is making a sample appearlarger.
    39. 39. RESOLUTION Resolution is the minimum distance separatingtwo points which still allows them to be seen astwo distinct points. The better the resolution, the better we seedetails of the image. Poor resolution results in a single blurry blob or“pixelation” when viewing on a computer screen.
    40. 40. MAGNIFYING ABLURRY IMAGEPRODUCES ALARGERBLURRYIMAGE!Magnification ismuch lessimportant tomicroscopythan resolution.
    41. 41. RESOLUTIONAdjust resolution byfocusing with this knob.X Do not focus with this knob!
    42. 42. ILLUMINATION OF OBJECTFROM ABOVE+ –Use +/- controlsto increase ordecreasebrightness
    43. 43. ILLUMINATION OF OBJECT FROMBELOWIlluminationfrom belowallows forviewing thinnerobjects thatallow light topenetrate.
    44. 44. USE TOP-LIGHTING FOR OPAQUEOBJECTS$5 bill magnified to show the striations of Lincoln’s beard
    45. 45. DIM LIGHT BRINGS OUT MOREDETAILPollen covering the stigma and style of a flower
    46. 46. TOP-LIGHT ON A LEAF SHOWS SURFACEDETAILHairs on a Rosemary leaf
    48. 48. FULL LIGHT FROM ABOVE ANDBELOWDracaena plant dead leaf (8x)
    49. 49. DIM LIGHT FROM ABOVE ANDBELOWDracaena plant dead leaf (8x)
    50. 50. DIM LIGHT FROM ABOVEONLYDracaena plant dead leaf (8x)
    51. 51. LIGHT FROM BELOW ONLYDracaena plant dead leaf (8x)
    52. 52. CARE OF THE MICROSCOPE Focus using the black focus knob. Do not use the zoom knob (smaller, upper knob)to focus. Use a petri dish under most samples. Do not use dissecting tools directly on microscopestage. Turn light off as soon as you are done. Cover when not in use to prevent dust and dirtbuild up.