Status of Seedlings in Greenhouses

Percent seed germination and uniformity of seedling stands in most greenhouses appear to be quite good. Clipping is underway in tray greenhouses and fungicide application for prevention of Rhizoctonia damping-off has occurred.

Only a few isolated problems have been reported to date. These include injury from fertilizer salts (float trays), excessively high temperatures (ventilation failure in a float tray greenhouse), algae on media surface (float trays) and bacterial soft rot (float trays).

Figure 1. shows damage to seedlings caused by Bacterial Soft Rot in a float tray greenhouse. Leaf debris falling back onto the seedlings from the clipper, as shown in Figure 2., is a good food source for the bacteria.  This is an ideal starting point for the disease to become established and have the potential to infect healthy seedlings.

Figure 1. Seedlings infected with Bacterial Soft Rot.

Figure 2. Leaf debris from clipper that has fallen back on to the seedlings.

There are no control agents registered for control of Bacterial Soft Rot in tobacco greenhouses. Removal of trays with the diseased seedlings from the greenhouse and replacing them with blank trays is the best control in this situation.  Other practices for control include trying to keep leaf debris from the clipper out of the beds, not clipping when the leaves are wet, not over-fertilizing, keeping the foliage of the seedlings as dry as possible, and ventilating the greenhouse adequately to keep the humidity level down in the greenhouse.

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