Tobacco float bed management

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By Bryce Roberts

Recent widespread reports of cutworm damage in float beds are a good reminder for tobacco growers to keep a close watch on tobacco float beds and greenhouses to catch and treat small problems before they become big ones.

A few worms can do a lot of damage in a day or two on small plants. Problems can occur on plants beginning at the 2-leaf stage. On small plants, up to dime-size portions of the plant may be missing. Upon closer examination, you often find just the stub of the stem remaining and possibly a few partially consumed plants. Sometimes you may find the culprit under the partially eaten plants, but often they burrow into the soil during the day. To control cutworms, your best bet is to use products that contain acephate at a rate of 1 tablespoon per 3 gallons of water. Spray to cover the plants and the tray surfaces. You may reduce cutworm problems if you control vegetation around the perimeter of the beds and spray acephate around the perimeter of the beds to limit the worms’ entry.

During extended periods of cloudy weather and high relative humidity, growers need to watch for stem rot disease in the float system. The float system provides favorable conditions for the development of these types of diseases. Several types of fungi, and occasionally some bacteria, can cause these rots. Spraying the wrong product can result in unsatisfactory disease control and loss of additional plants. So it pays to take a tray to the local extension office and have the problem identified.

Some general recommendations for reducing rot problems in tobacco greenhouses include:

•Maintaining the fertilizer level in the recommended range of 75 to 125 parts per million nitrogren.

•Manage humidity levels by flushing the air inside the greenhouse several times a day and even during the nighttime hours.

•Maintaining the water levels such that the top of the trays are above the level of boards; this encourages improved air flow at the tray surface.

•Using good clipping practices to improve air flow and light penetration.

•Clipping only when foliage is dry and using a sharp and slow blade to remove the clipped material without grinding. Any material that falls back to the tray has the potential to spread disease to surrounding plants.

•Burying or disposing of clipped material at least 100 yards from the float bed.

You should examine your float beds at least once a day so you can catch any problems early and take appropriate measures to protect young tobacco plants.

Feel free to contact me at your Spencer County Cooperative Extension Service at 477-2217 or you can email me at broberts@uky.edu.  You can visit the Spencer County Extension Services’ website at www.spencerextension.com.

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