In a multi-year study, Masood Khezri, Research Director at MARI Agricultural Research Institute, highlighted the importance of timing Dormex applications based on chill conditions for maximum effectiveness. So far, the material has been shown to benefit pistachio trees in both adequate and low-chill scenarios. “We plan to continue our research over more years to gain a better understanding of the details regarding the right timing and pistachio tree response under variable conditions,” Khezri explained.
Multiple years of research under different environmental conditions will allow the researchers more opportunity for more comprehensive understanding of tree response. This winter has thus far been somewhat behind last year in terms of chill accumulation. Khezri emphasized the importance of using field weather stations or CIMIS stations to monitor chill portions, to know when applications would be most beneficial. The calendar date should also be taken into account when considering chill conditions.
For growers considering Dormex, Khezri recommended applying it to different rows at different locations within the orchard. “I also suggest harvesting those particular rows separately recording the numbers and conducting a comparison. This helps them determine if this chemical is a suitable option for their fields, especially in marginal or low-chill years or low-chill locations,” said Khezri.
Information from the UC Davis Chill Calculator shows that as of February 13, the Durham CIMIS station has logged 63.6 portions under the dynamic model, with 871 hours below 45°F. The station in Manteca has registered 59.9 portions, with 713 hours. There have been 929 hours in Merced, with 58.3 cumulative portions. In Five Points, there have been 763 chill hours, equating to 56.9 portions. Finally, the CIMIS station in Shafter has registered 53 portions, with 751 hours.
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