This is a follow up to last week’s article “Use of Promalin for Frost Rescue—Updated Recommendations”. I wanted to provide additional guidelines on the use of Promalin, specially after the frost events we have experienced this week, and yesterday in the Door Peninsula.

1. You must assess damage by dissecting flowers even if they have not fully open yet and check for brown coloration in the pistil. Here’s a video on assessing damage. Remember that you don’t need all the flowers in a cluster to be viable to have a full crop. So even if you have some damage to kings, if laterals are still viable there is a very high chance you will have a full crop.
2. If your trees are at the tight cluster or early pink stage, refrain from applying Promalin as it will not yield any benefits. Wait until king flowers open, remember that you have a 5-day window after the frost event to apply Promalin and still have good results.
3. Promalin will not protect flowers from getting cold damage, or repair flower damage. Promalin works by stimulating the retention of fruit with unviable seeds that otherwise would have dropped, that’s why applications at tight clusters or early pink are not very effective.

This article was posted in Apples and tagged Amaya Atucha, Apples, frost rescue, Promalin.