Float Bed Disease

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

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

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

Pythium sp.

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

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

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 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 - 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

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

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

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

Anthracnose

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