Tuesday, September 2, 2008

Bramble Fungicide Sprays

As a result of the rain last week and the possibility of more rain from Gustav, Hanna and Ike, blackberry and raspberry growers should think about disease control options. Dr. Gina Fernandez of the horticulure department at NCSU was kind enough to pass along some information from Plant Pathologists Dr. Phil Brannen (UGA) and Dr. Turner Sutton (NCSU).

From Phil Brannen big issues for FLORICANE fruiting types:
1. Pruning wounds and cane blight. Dr. Brannen recommends suspending pruning until dry conditions are predicted for several days. Applications of Prisitine or another broad-spectrum fungicide to pruning wounds after each day of pruning is recommended.
2. Leaf spots. Leaf spots will also likely develop and early defoliation due to pathogens like Septoria and others is possible, so a preventative spray ahead of heavy sustained rains may be helpful. A broad-spectrum material, like Prisitine, would be good for control of these pathogens with application 24-h prior to rains being the ideal.
3. Orange cane blotch. Dr. Brannen suggests the consideration of copper application both ahead of and following the storms in order to suppress orange cane blotch. Copper materials are not great, but they are still the best products available for the algal disease.
4. Phytophthora. If winds are severe, tearing of roots and the entry of Phytophthora is possible. Application of ProPhyt or other Phosphonate materials are recommended. Where possible, drip-applied Ridomil Gold either before or after the rain can be used.

From Turner Sutton big issues for PRIMOCANE fruiting raspberries and blackberries:
"Anyone with fruit needs to spray asap if they haven't already. (As soon as it stopped raining would have been an ideal time)."
1. Botrytis and other fruit rots. CaptEvate (a broad-spectrum fungicide with a 3-day phi) may be a good choice than a botrytis-specific fungicide. Alternatively, Captan + a botrytis fungicide can be applied (check the phi).
2. Leaf spots. Monitor leaves of primocanes closely (at least weekly) for leaf spots or rusts. You do not want to lose a lot of leaves before frost to predispose then to winter injury. If rust is not a problem, Captan is okay and is the least expensive.
3. Phytophthora. Phytophthora is typically not a problem until the soils cool in late Sept/Oct, unless you are in very heavy wet soils. Sutton also recommends a phosphite foliar spray at this time.
*Thanks to Dr. Fernandez, Dr. Sutton and Dr. Brannen for this great information. As always, follow manufacturers' guidelines on the fungicide label.*