Potato Virus Y (PVY) has been identified in several tobacco fields in the past week.  The virus can produce symptoms of leaf mottling (click here for photo), prominent leaf veins and blackening (i.e. necrosis) of the veins especially on the undersides of the leaves (click here for photo).  Plants infected early with PVY appear stunted, while later infected plants may not be and instead have symptoms limited to the upper leaves.  Infected plants or leaves will die, turning brown or yellow.  PVY is transmitted by aphids from plant to plant, so consider early treatment of the crop with an insecticide registered for their control to help limit disease spread.  Unlike Tobacco Mosaic Virus (TMV), PVY does not persist in tobacco crop debris from season to season.

The flue-cured tobacco hybrid CTH8 is now registered for Canadian use.  CTH8 was developed by the Canadian Tobacco Research Foundation.  In field trials, it has proven to produce superior quality with good yield potential.  Seed growers will be producing seed of CTH8 in 2013 so that it can be available commercially for the 2014 crop.

Cultivation is now occurring on most farms.  There does not appear to be any widespread problems at this time.  Transplants are establishing well and showing good growth in recent days.

Several growers have now finished planting.  Those that haven’t will be done soon.  The most significant problem during planting was damage to some of the earlier plantings from frost.  These fields have either been planted-over or replanted.  Currently, there are no significant problems being reported.  Recently, we have had a few calls about plants set out on Monday, June 3 showing some physical damage from environmental stresses.  Some of the plant leaves turned a silvery/white colour and some of the weaker plants did not survive.

Several growers have started planting.  To date, no significant field problems have been encountered.  In greenhouses recently, there was a confirmed case of Rhizoctonia Damping-Off and reports of Target Spot (Rhizoctonia Leaf Spot).  When planting seedlings from greenhouses where these diseases are present, it would be best to check the stem of seedlings to ensure there is no rot showing.  Sore-Shin can occur in the field with seedlings that had rot on the stem from the greenhouse.  Greenhouse seedlings showing rot on the stem should be discarded and not used in the field.

Several growers are reporting chilling injury (click here for photo) to seedlings in their greenhouses.  A large variation in temperature in the greenhouse can cause chilling injury.  Seedlings will grow out of this condition without any ill-effects.

Overall, seedling stands in greenhouses should provide adequate transplants for this year’s crop.  There have been a variety of issues observed in greenhouses, but none of these is widespread.  Some of the issues that have been seen include slow seed germination, uneven seed germination and seedling growth, algae formation on the surface of media interfering with seedling emergence and growth, nutrient deficient seedlings and chilling injury to seedlings.  Routine clipping has started in some float tray greenhouses.

We have received calls from growers regarding optimum temperatures for seed germination and seedling growth. The optimum temperature for germination is 24°C or 75°F. Some growers will maintain at least 21°C or 70°F for the first 14 days to maximize the speed of germination and plant uniformity. It is recommended that at least 15°C or 60°F or higher be maintained during the first 14 days otherwise an uneven plant stand could occur.

CTH8 has been recommended by the Flue-Cured Tobacco Variety Evaluation Committee for registration.  CTH8 is an F1 hybrid developed by the Canadian Tobacco Research Foundation.  In field trials, it has proven to produce superior quality with good yield potential.  The seed growers will be producing seed of CTH8 in 2013 so that it can be available commercially for the 2014 crop.

From now and until the end of this month, growers are starting their greenhouses. Optimum temperatures for germination and seedling growth are needed in plug tray greenhouses to maximize seedling uniformity and yield.