Safety and efficacy of potential herbicides for use in date palm

Authors: MAUK, P - University Of California, Riverside; Krueger, Robert; LI, R - University Of California, Riverside

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 9/1/2023
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: In the United States, date palms, Phoenix dactylifera, are only produced California and Arizona. In 2021, the acreage of date palms in California was 12,200 acres and in Arizona was 4,000 acres. Currently, there are 3 herbicide active ingredients registered for use on date palm, caprylic/capric acid, pendimethalin and glyphosate. Pendimethalin is registered for non-bearing date palms. Glyphosate is registered for bearing date palms and is under increasing political scrutiny in California. To determine if there are other herbicides that are effective and do not cause crop injury, we conducted studies evaluating the phytotoxicity and efficacy of several herbicides. The herbicides selected for testing were based on input from growers and registrants. Pre-emergent treatments included 2 rates of flumioxazin, oxyfluorfen+penoxsulam, pendimethalin, rimsulfuron, and indaziflam. Post-emergent treatments included 2 rates of glufosinate, 2,4-D choline, florpyrauxifen and saflufenacil. Glyphosate was used as the grower standard. Evaluations included weed density, weed diversity, and plant phytotoxicity from simulated spray drift. Pre-emergent herbicides were applied at 3-month intervals for a total of 3 applications/year and evaluations were conducted on 15-, 45-, and 90-day intervals. Post-emergent treatments were applied every 30 days for a total of 3 applications/year with evaluations conducted at 7-, 14- and 30-day intervals. Results for selected pre- and post-emergent herbicides are encouraging, there are several products that show potential.