Throughout California growers have seen significant drop within their Monterey variety. Discussions this past week within our in-service farm advisor tour concluded that this drop is most likely due to cold damage.Cold temperatures, in the low 30’s, were experienced (and confirmed) in April throughout the Sacramento and San Joaquin Valleys.
Although we are not certain, the damage observed appears to be an abiotic (non-disease) issue due to the following evidence:
1. Drop has been observed in multiple regions of California,
2. Drop was observed in multiple orchards with varying cultural practices,
3. Damage in some orchards appears to be in the lower spots,
4. Nuts are without disease symptoms of any kind,
5. The problem appears physiological.
Through the process of elimination, Joe Connell (Butte Co Farm Advisor) began to consider cold damage. Upon looking back at the records, he noted that cold temperatures were experienced for several nights. Since varieties differ in their cold sensitivity, not all varieties were affected. Information regarding the sensitivity of Monterey to cold has not been researched, which leaves the possibility of this variety being more sensitive to other commonly planted varieties (i.e. Nonpareil, Butte, etc.). Connell’s thoughts were supported by observations from Roger Duncan (Stanislaus Co. Farm Advisor).
If you are concerned about the drop you are experiencing within your almond orchard, please call your local farm advisor to discuss the various reasons in order to reduce the possibility of re-occurrence.