Transcript Float Bed Disease

Float Bed Disease
Diseases - Bacterial
Black leg - Erwinia sp.
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Same as hollow stalk &
barn rot (houseburn)
Black area at base of stalk
(often splits stalk)
Ubiquitous
influenced by N fertility
Control
 by monitoring fertility
(not over 150 ppm N)
 Streptomycin
 Limited benefit
Diseases - Bacterial
Angular Leaf Spot Pseudomonas syringae
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Limited by leaf veins
making spots angular
in shape
More prevalent in
outside beds exposed
to rainfall
May be zonal on
windward side of leaf
Control
 Stretomycin
Diseases - Fungal
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Damping-off - Pythium sp.
 Brown to black rot at base of plant
and roots
 Roots are often straw colored and
hang limp down the tray when tray is
held vertical
 Water/soil borne fungi
 Clean water source
Pythium sp.
Pythium sp.
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Control
Terramaster 4EC
0.7 fl oz/100 gal Preventative
1.4 fl oz/100 gal Curative
Possible Root Stimulation
Terramaster 4EC controls growth
of algae
Source: W. Gutierrez & T. Melton, North
Carolina State University, 2000
Terramaster
phytotoxicity
- Shoots
Phytotoxicity Roots &
Recovery
Does Terramaster Cause Premature
Bloom?
Diseases - Fungal
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Target Spot - Rhizoctonia leaf spot Rhizoctonia solani
 Small water-soaked spot initially
 Concentric circles or target
 Favored by
 low fertility
• Rainfall dilution of outside bed
• Reduction of N to slow plants
 Maturity
Target Spot
Target Spot - Control
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- Dithane
 1 tsp/gal using 3 to 12 gals per 1000 sq ft
or 400 trays depending on size of plants.
Start when plants are at least the size of a
dime
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Carbamate
 1.5 to 3 tsp/gal using 3 to 12 gals per 1000
sq ft or 400 trays depending on size of
plants.
 Leaves black residue/easy to see
Sore shin
Rhizoctonia solani
Reddish-brown sunken lesions on stem
of plants
 Can come from target spot infections
 See above
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Collar rot
Sclerotinia sclerotiorum
Small black-brown (straw colored) lesion at
base of plant that may increase in size to
encircle plant, killing plant
 May spread into leaves
 Noticed as softball sized dead area
 White mycelium
 Sclerotia
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Collar rot - Sclerotinia
Anthracnose
Colletotrichum gloeosporoides
Small, light green, water-soaked pinpoint
spots that enlarge to oily circular spots up
to 3 mm in size
 develop into thin, papery, gray-white
 Known to spread from grasses
 Control
 Sanitation
 Same for Target Spot
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Anthracnose
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Contaminated trays
 New trays versus old
Bleach 10%
Steam
 much reach 140o F for
30 min
o
 180 F damages Trays
Methyl Bromide
 Cheap
 Quick
 Dangerous
 Temperature
dependent
 Environmental concerns
Tray
sterilization