Good Class4 Ornamental Diseases

3,344 views

Published on

Published in: Technology
1 Comment
5 Likes
Statistics
Notes
No Downloads
Views
Total views
3,344
On SlideShare
0
From Embeds
0
Number of Embeds
43
Actions
Shares
0
Downloads
0
Comments
1
Likes
5
Embeds 0
No embeds

No notes for slide

Good Class4 Ornamental Diseases

  1. 1. Ornamental Plant Diseases Commercial Pesticide Applicator Exam Preparation Laura Pottorff, Colorado State University Adams County
  2. 2. Diseases Caused by Fungi • If the cause affects leaves/flowers only – Fungi • Powdery mildew • Botrytis • Rust • Anthracnose • Marsonnina • Apple scab • Septoria leaf spot
  3. 3. Common characteristics of fungi that affect leaves/flowers • Live above ground • Spread via wind, water, insects • Often require a water film on leaf surface to germinate and penetrate plant tissue. • Often overwinter on plant debris.
  4. 4. Powdery mildew on poinsettia
  5. 5. Powdery mildews • Produces talcum powder-like growth on leaf surface. (Sign) • Many, many plants are susceptible (even weeds).
  6. 6. Powdery mildew • Example: – Western sand cherry
  7. 7. Powdery mildew • Fungus overwinters on leaf debris • Favored by – shade, poor air circulation
  8. 8. Powdery mildew management • Clean up leaf debris. • Improve air circulation with selective pruning. • Fungicides – Potassium bicarbonates, Oils, Sulfur, Neem – Cleary’s 3336, Eagle, Bayleton
  9. 9. Botrytis (Gray mold) • Fungus produces gray mold on surface of flowers, fruit, leaves, and stems.
  10. 10. Botrytis • Favored by • Management – high humidity – Clean up debris – Poor air circulation – Good plant culture – Wounded or weakened – Avoid over watering tissue – Avoid over fertilization – Many of the same fungicides as for powdery mildew control *follow label directions.
  11. 11. Rust diseases • Two types – single host • sunflower rust • snapdragon rust • rose rust – two hosts • Juniper - Hawthorn rust
  12. 12. Juniper - Hawthorn Rust • Rocky Mt. Juniper – Galls
  13. 13. Juniper - Hawthorn Rust • Hawthorn – Leaf spots
  14. 14. Cedar/apple rust leaf Cedar/apple rust “spores” on leaf spots on crabapple underside of crabapple June-August August - April April - June Cedar/apple rust gall on juniper Cedar/apple rust “spore horns” on juniper
  15. 15. Juniper Hawthorn Rust Management • Separate hosts • Prune out galls on juniper • Clean up leaves in autumn on hawthorn • Fungicides – Juniper • Bordeaux mixture – Hawthorn • Bayleton, Cleary’s 3336
  16. 16. Day Lily Rust • Native to China, • Main way of spread Japan, Korea, Taiwan, – Airborne spores Russia • Be on the look out – Not yet in Colorado • Heteroecious rust – Day lily – Patrinia (lily family) – Hosta? (lily family) Diagram: M. Hahn and K. Mendgen, Konstanz University
  17. 17. Day Lily Rust • First found in U.S. in December 2000 • Due to nature in which plants are moved about there is concern • We do not know how serious this disease will be
  18. 18. Day Lily Rust
  19. 19. Daylily rust • Symptoms
  20. 20. Day Lily Rust • Not Daylily rust
  21. 21. Day Lily Rust • Signs
  22. 22. Day lily Rust management • Fungicides known to be affective against rust and labeled for day lily – Banner Maxx (propiconazole) • home owner version – Fertilome liquid systemic fungicide – Contrast (flutalonil) – Heritage (azoxystrobin) – Systhane (myclobutanil) – Daconil – Mancozeb
  23. 23. Apple Scab (Venturia inequalis) • Hosts: Apple, Crabpple, Malus spp. • Symptoms
  24. 24. Apple Scab • Favored by • Management – Wet spring – Clean up leaf debris in fall – Poor air circulation – Fungicides normally – Certain varieties more not needed. susceptible • Radiant crabapples
  25. 25. Anthracnose Anthracnose
  26. 26. Anthracnose • Anthracnose is a term • Hosts: oak, sycamore, for a type of leaf spot ash, and many other disease. ornamentals • Blotchy, necrotic lesions. • Normally not serious. • Outbreaks dependent on spring weather conditions.
  27. 27. Anthracnose • Life cycle: – fungus overwinters on leaves that fall to the ground in autumn. – Spores become active in spring and blow up to newly emerging leaves. – Favored by spring moisture.
  28. 28. Anthracnose • Management: – clean up leaf debris – allow for better air movement – fungicides are normally not needed
  29. 29. Marsonnina leaf spot on aspen
  30. 30. Marsonnina leaf spot • Host: Aspen • Damage: Yearly infestations may weaken tree. Causes premature leaf drop. • Normally not a concern in native areas (except for ruining fall color) • In landscaped areas may detract from look of tree.
  31. 31. Marsonnina leaf spot • Symptoms – dark black spots on leaves
  32. 32. Marsonnina leaf spot • Life cycle: – Fungus overwinters on leaf debris – Will spread to newly emerging leaves in the spring. – Symptoms visible in late summer - fall.
  33. 33. Marsonnina leaf spot management • When symptoms are visible (late summer): – Clean up leaf debris – IT IS TOO LATE TO SPRAY • If a fungicide application is warranted – Apply in the spring during bud break • Cleary’s 3336 • 26GT
  34. 34. Septoria leaf spot Photos:Government of British • Hosts: Cottonwood, Columbia- Forest Services maple and dogwood • Round leaf spots with dark margin • Fruiting structures within tan interior of leaf spot Fruiting structures
  35. 35. Integrated Pest Management of Fungal Leaf Spots • Clean up leaf debris (sanitation) • Avoid moisture on leaf surface • Decrease relative humidity • Improve air circulation • Is the plant located in the “right place” • Optional – Funigicides
  36. 36. Examples of Alternative Fungicides Labeled for Most** Leaf Spots • **READ THE LABEL!!! – Copper sulfate (anthracnose, powdery mildew, juniper tip blights) – Neem oil (Triact, Rose Defense) for powdery mildew – Potassium bicarbonate (Kaligreen, First Step) for powdery mildew – Sulfur (powdery mildew, black spot)
  37. 37. How do we get rid of it? (Integrated Pest Management) • If the cause affects leaves/flowers (and stems) only – Bacteria • Fire blight
  38. 38. Spring - Summer Fire blight cycle Shepherd’s crook Canker
  39. 39. Fire blight cycle Summer - Winter
  40. 40. Integrated Pest Management of Fire blight • Prevention • Control – Resistant varieties – Removal of • Crabapples symptomatic branches – Centurion (disinfect tools – David between each cut) – Indian Summer – Molten Lava – Pesticides – Profusion • Streptomycin sulfate – Robinson (for agricultural use – Biological control only) • Blight Ban (Pseudomonas • Copper flourescens)
  41. 41. Bacterial blight (Pseudomonas) • Hosts: Lilac, • Symptoms: blackened stems, petioles, and Cotoneaster leaves. Shepherds crook. • Occurs in spring • Commonly confused with frost injury Photos from Cornell University
  42. 42. Bacterial Blight • Management – Dry spring weather is a natural control – Prune out diseased branches, disinfecting pruning tools between each cut. – Results from chemical control are often unsatisfactory
  43. 43. Bacterial Wetwood • Hosts: Cottonwood, • Callus formation Siberian Elm, Willow retarded • Smelly, ooze running down trunk
  44. 44. Bacterial wetwood • No effective methods exist to eliminate wetwood disease. Preventing damage and stress to a tree's roots and stem is the best way to avoid a serious wetwood problem. Drought conditions increase wetwood problems, so it is important that the tree receives adequate water, especially during spring and summer months.
  45. 45. Crown Gall Agrobacterium tumefaciens • Hosts: Stone and pome fruits, roses, cottonwood, junipers, grapes. • Symptoms: wilting, gall at crown line or on roots.
  46. 46. Crown gall management • Bacterium is soilborne • Remove plant • Replant with nonsusceptible species • Avoid root wounding
  47. 47. How do we get rid of it? (Integrated Pest Management) • If cause (who) only affects stems – Fungi • Cankers Canker caused by bacteria Canker caused by fungus
  48. 48. Dieback caused by?
  49. 49. So What??? Cytospora? Fruiting structures = fungus Thyronectria?
  50. 50. Dieback caused by?
  51. 51. Girdling
  52. 52. Integrated Pest Management for Canker diseases • Remove affected branch. • Remove entire plant if on main stem. • Optional – Improve health of plant • Fungicides are not effective
  53. 53. Vascular wilts • If the cause (who) only affects internal plant tissues – Fungi • Dutch Elm Disease (Vectored) • Verticillium wilt (soilborne)
  54. 54. Vascular wilt disease – Can also move • Dutch elm disease between trees through – Vectored by the elm root graphs bark beetle
  55. 55. Integrated Pest Management for Dutch Elm Disease • Prevention • Control – Resistant varieties – Remove tree – Fungicide injection – Trench potential root graphs • Arbotect (benzimadazole) – Control vector • Alamo (propioconazole) Fungicide injection Photo by Lise Mahnke
  56. 56. Vascular Wilt Disease • Verticillium wilt • Gray to olive brown vascular streaking – Soilborne fungus – Many types of plant hosts • Woody • Herbaceous
  57. 57. Integrated Pest Management of Verticillium Wilt • Prevention • Control – Rotation of host plants – Removal of tree (not mandated) – Resistant tree varieties – Fungicides not • Hawthorn effective • Honey locust • All conifers • Apple/Crabapple/Pear • Sycamore • Oak • Willow • Mt Ash • Linden
  58. 58. • Dieback caused by?
  59. 59. Girdling root
  60. 60. Problems affecting roots • If cause (who) only affects roots • Biotic – Fungi (Pythium, Rhizoctonia) • Abiotic – Root girdling – Oxygen starvation – Etc.
  61. 61. Symptoms of root rot • Soft brown mushy roots – Sloughing of cortex
  62. 62. Integrated Pest Management for Fungal Root Rots • Biotic – Avoid over watering/improve soil drainage – Destroy severely affected plants – Optional • Fungicides
  63. 63. Fungicides Labeled for Most** Root Rot Fungi • **READ LABEL DIRECTIONS – Rhizoctonia or Fusarium • Iprodione (Chipco 26019) • azoxystrobin (Heritage) • Thiophanate methyl (Cleary’s 3336) • Trifloxystrobin (Compass) • Gliocladium virens (Soilguard) - Biological
  64. 64. Fungicides Labeled for Most** Root Rot Fungi • **READ LABEL DIRECTIONS – Pythium or Phytophthora • Metalaxyl (Subdue or Chipco Signature) • azoxystrobin (Heritage)
  65. 65. Abiotic Diseases • environmentally induced disease • the precursors or primary plant problems – lead to plant stress/weakness – lead to invasion of insects and disease
  66. 66. Affecting Roots • Soil condition and drainage is the primary problem
  67. 67. Affecting roots (and leaves) • Abiotic- 80% of all landscape plant problems fall this category
  68. 68. Affecting Roots (and leaves) • oxygen starved roots
  69. 69. Colorado Blue spruce located on south facing slope in urban landscape.
  70. 70. Plant siting • Natives and adapted non natives can be Ginnala maple planted together. – Watch that moisture regimes are similar Yucca
  71. 71. Affecting Roots (leaves symptomatic) • Nutrient deficiency – brought on by • soil condition • excess moisture – oxygen starvation
  72. 72. Affecting roots (leaves symptomatic) • Leaf scorch – an imbalance between water uptake and loss.
  73. 73. Affecting Leaves External “pressures” typically “blow” in.
  74. 74. Leaves affected – Freeze
  75. 75. Affecting leaves • 2,4-D herbicide injury to Ginnala maple
  76. 76. Is a Chemical Necessary? – Is the host plant valuable? – Is the pest/disease properly identified? – Is the disease life- or health-threatening? – Does this plant have a history of disease? – Are effective, legal treatments available? – Will one or two applications suffice? – Have cultural control practices been used?

×