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Lecture 16 Turf, Flower and Vegetable Diseases. Turf diseases. Fusarium patch, red thread disease, fairy rings and thatch are common in Seattle. Flower diseases. Azalea – leaf and flower gall Camellia – cold damage
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Turf diseases Fusarium patch, red thread disease, fairy rings and thatch are common in Seattle
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
Botrytis (Grey mold) Rose Cherry
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
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, there’s more!!
Rose Diseases and Common Methods for Control 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. 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
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.
Other Diseases Crown Gall Angrobacterium tumefaciens Botrytis Blight Botrytis cinerea Rose Rust Phragmidium ssp.
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
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
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.
LettuceBacterial Soft Rot Symptoms • Rotting of the edges of lower leaves • Leaves of the head finally dissolve into an unappetizing, slimy rot.
White mold Sclerotinia rot A fungal disease which may attack the stems, leaves, and pods of beans.
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.
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.