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. Control Terramaster 4EC0.7 fl oz/100 gal Preventative1.4 fl oz/100 gal Curative Pythium sp.

7. Possible Root Stimulation

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 Rhizoctoniasolani • 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