UC Cooperative Extension Orchard Systems Advisor, Kat Jarvis-Shean has been working on solutions for growers dealing with chill shortages. Historically, discussions surrounding chill accumulation have often concluded with limited recourse for growers. However, research is showing that nut producers have some options available to them to help with a lack of chill hours.
“UC has been diligently engaged, and several chemical companies have endeavored to provide tools for walnut growers,” Jarvis-Shean noted. “Resources traditionally available to fruit cultivators but historically lacking for those involved in nut crop cultivation.”
Collaborating with the Walnut Board, the California Department of Food and Agriculture, and manufacturers, researchers have been testing viable solutions for chill shortages. “Our research indicates a robust response in advancing bud break timing. Dormex, in particular, has demonstrated a remarkable ability to compensate for the deficiency in chill, effectively influencing bud break timing,” Jarvis-Shean explained.
The introduction of these tools into the grower’s toolbox signifies a crucial step toward addressing an age-old problem. While the research is still evolving and undergoing thorough checks for data quality, the implications are significant for walnut growers facing chill challenges. Jarvis-Shean said that initial data has shown that Dormex specifically has been able to help increase overall bud break, not exclusively move bud break timing. “All of that is still rapidly evolving and working towards publication and data quality checking and getting it out there,” said Jarvis-Shean.
Information from the UC Davis Chill Calculator shows that as of December 26, the Shafter CIMIS station has logged 23.9 portions under the dynamic model, with 440 hours below 45°F. The station in Five Points has registered 25.4 portions, with 475 hours. There have been 594 hours in Merced, with 26.5 cumulative portions. In Manteca, there have been 463 chill hours, equating to 28.3 portions. Finally, the CIMIS station in Durham has registered 30.8 portions, with 527 hours.
Listen to the segment below.