1. Float Bed Disease

2. Diseases - Bacterial Black leg - Erwinia sp.
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

3. Diseases - Bacterial Angular Leaf Spot - Pseudomonas syringae
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

4. Diseases - Fungal 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

5. Pythium sp.

6. Pythium sp.
Control Terramaster 4EC 0.7 fl oz/100 gal Preventative 1.4 fl oz/100 gal Curative

7. Possible Root Stimulation
Producers often described the root systems where terramaster had been applied

8. Terramaster 4EC controls growth of algae
Source: W. Gutierrez & T. Melton, North Carolina State University, 2000

9. Terramaster phytotoxicity - Shoots

10. Phytotoxicity -Roots & Recovery

11. Does Terramaster Cause Premature Bloom?

12. Diseases - Fungal
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

13. Target Spot

14. Target Spot - Control - 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
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

15. Sore shin Rhizoctonia solani
Reddish-brown sunken lesions on stem of plants
Can come from target spot infections
See above

16. 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

17. Collar rot - Sclerotinia

18. 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

19. Anthracnose

20. Tray sterilization Contaminated trays New trays versus old Bleach 10%
Steam
much reach 140o F for
30 min
180o F damages Trays
Methyl Bromide
Cheap
Quick
Dangerous
Temperature
dependent
Environmental concerns