Lecture 16 Turf, Flower and Vegetable Diseases

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Lecture 16Turf, Flower and Vegetable Diseases
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Turf diseases

• Fusarium
  patch, red thread disease,
• fairy rings and thatch are
  common in Seattle

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Flower diseases

• Azalea leaf and flower gall
• Camellia cold damage
• Cherry brown rot, Botrytis
• Geranium Botrytis blight
• Lilac Botrytis flower blight
• Narcissus chocolate spots?
• Pansy Botrytis blightPetunia Botrytis blight
• Rhododendron flower bud damage (frost)
• Rose everything
• Tulip fire Botrytis, virus

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Botrytis (Grey mold)
Rose
Cherry
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Roses have earned the reputation of one of the
most susceptible plants to diseases and pests
chemical fungicides and pesticides are widely
used both by growers and home gardeners Some
growers now raise roses organically without
chemicals, e.g., https//www.ashdownroses.com
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A listing of known diseases that affect roses

• Described Rose Diseases
• Rose Anthracnose
• Rose Bacterial Blight
• Rose Black Spot
• Rose Botrytis Blight
• Rose Cankers
• Rose Crown Gall
• Rose Downy Mildew
• Rose Hairy Root
• Rose Leaf Spots
• Rose Powdery Mildew
• Rose Rust
• Rose Spring Dwarf
• Rose Mosaic Virus

Believe it or not, theres more!!
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Rose Diseases and Common Methods for Control

• Best way to prevent powdery mildew and other
  diseases without using chemicals!
• Clean up fallen leaves, deadheads and other
  debris. DO NOT COMPOST!
• Allow adequate space for plants when planting to
  ensure good air circulation.
• Avoid overwatering, overhead watering, and
  applying too much fertilizer.
• Plant resistant varieties

• Powdery Mildew
• (Sphaerotheca pannosa)
• Overwinters in infected buds, canes and fallen
  leaves and attacks young spring growth.
• Thrives in areas with high relative humidity at
  night when temperatures are around 60 degrees F.
• Also thrives at around 80 degrees F with 40-70
  RH.

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Blackspot (Diplocarpon rosae)

• Infects foliage and stems causing defoliation and
  weakens plant.
• Presence of water on plant surface for 7-8 hours
  is needed for infection.

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Other Diseases
Crown Gall Angrobacterium tumefaciens
Botrytis Blight Botrytis cinerea
Rose Rust Phragmidium ssp.
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Common Diseases of the Home Vegetable Garden
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Carrot - Root Knot NematodeMeliodogyne spp.

• Microscopic, live in soil
• Feed on roots
• Distortion of roots
• Stunted roots, short bushy root hairs
• Yellow or stunted leaves

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CrucifersBlack RotXanthomonas campestris

• Bacteria
• Enters through wounds on leaves
• Leaves yellow and die in V shaped pattern from
  margin to midrib
• Leaf Drop
• Spreads through xylem to other parts of plant

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Blossom End Rot

• Symptoms
• First appears as a brown discoloration at blossom
  end of fruit.
• Spot enlarges and darkens, eventually becoming
  sunken and leathery.
• Soft Rotting may occur if secondary fungi or
  bacteria invade the spot.

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LettuceBacterial Soft Rot Symptoms

• Rotting of the edges of lower leaves
• Leaves of the head finally dissolve into an
  unappetizing, slimy rot.

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White mold Sclerotinia rot

• A fungal disease which may attack the stems,
  leaves, and pods of beans.

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Potatoes Powdery Scab is caused by a fungus,
Spongospora subterranea, that is carried on the
seed and can survive 3 to 10 years in the soil.
Signs Purple to brown scabby areas or warty
lesions on the surface of the tuber. Small galls
and warts may form on roots of some potatoes.
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Corn Smut

• A fungus (basidiomycete),
• Ustilago zeae, overwinters
• in soil as teliospores, that
• may survive 2 or 3 years.
• Spores may be wind blown
• long distances.