We have been hearing of reports of uprights exhibiting classic symptoms of frost damage, known as umbrella bloom. In addition to frost injury, umbrella bloom is also associated with insufficient chilling hours; there are also reports of this type of damage from mites or insects, but we have not seen this much in MA. With umbrella bloom, the upright has flowers at the tip but there is no vegetation above the flowers (see photo below). This is due to the injury to the vegetative meristems (growing tissues) that were in the bud at the time of the frost event/injury. Typically, one expects 1-2 or more inches of new growth above the flowers. Despite the number of blooms present, the consequence of having no tissue above the fruit means less food (carbohydrates) to support fruit development. There can be enough reserves for the plant to support some fruit but the reports from growers are mixed about how many fruit will be supported; in general, we (MA) tend to see a yield reduction with umbrella bloom.
We have also been seeing some tip flashing. This is often associated with use of Callisto. It should pass in a week or two. If you haven’t used Callisto and see these symptoms, please let us know.
You should be getting your out of bloom counts so you can schedule your first fruitworm spray. Please see last week’s IPM message for details on how to calculate oob. You can call me at the station, and I am happy to walk you through it.
Second fungicides are going out and many growers are applying early set fertilizers now. Typically, the largest dose goes out at this time. Remember, the super hybrids will need extra nitrogen to support the leaves that will support the fruit. As always, it’s a balance between having enough leaves to support the fruit and too much vegetation that fosters fruit rot.
Please let me know if there are any issues you would like to see address on the IPM message
