Luke Milliron, UCCE Orchard Systems Advisor; Butter, Glenn, and Tehama Counties
Franz Niederholzer, UCCE Farm Advisor, Colusa, and Sutter/Yuba Counties
Katherine Jarvis-Shean, UCCE Orchard Advisor, Sacramento, Solano, and Yolo Counties
Please note that the following are general recommendations intended to help you keep track of regular practices in a busy time; the optimal timing for management practices may vary based on specific location and conditions.
- Drought: This will be a tough irrigation season for many growers. For a review of drought management strategies, download the free UC publication Drought Management for Almond Orchards.
- Irrigation: Monitor stem water potential using the pressure chamber and soil moisture sensors for irrigation timing (when and how long). Information on pressure chamber use is available in the ‘Manuals’ section of this site. Information on soil moisture monitoring can be found in this PDF from UC ANR. The pressure chamber is a more accurate measure of water status under saline soil/water conditions than soil moisture or ET.
- Water Quality: Do you know what is in your irrigation water? Overall salinity, chloride, sodium, and boron can change with source (canal vs. well) and time of the year. Consider taking a water quality sample (see our article on irrigating with low quality water).
- Spring Diseases: For diseases such as rust, anthracnose, shot hole, scab and alternaria you can learn more about efficacy, timing, and mode of action (MOA) rotation options in the fungicide and bactericide efficacy and timing tables included in this newsletter. For the best disease control, spray before rain. Alternate fungicide chemistry (FRAC groups) to reduce resistance. You can learn more about these diseases on the UC IPM website.
- Gophers kill almond trees. Also, the combination of gopher mounds and close mowing produce more dust-induced spider mite pressure. Manage gophers early on, before their March through May reproductive pulse boosts populations. The best time to look for fresh mounding activity for implementing control measures is approximately 48-72 hours after rainfall or irrigation. See more on gopher control in our article about Options for Gopher Management. Trapping is an excellent means of controlling gophers. Better trapping results have been measured when employees are trained to find tunnels and set traps. See video showing steps to gopher trapping with Dr. Roger Baldwin, UC Extension Specialist.
- NOW monitoring: Continue monitoring traps, checking egg traps twice weekly to determine biofix. Many experienced practitioners in the Sacramento Valley use the first NOW eggs found in traps as the biofix. This differs from common practices in the San Joaquin Valley because our population pressure is often lower. Pheromone and bait-bag traps can be used to track male and female flights and relative abundance. Additional details on NOW management on the UC IPM Website.
- Shoot Strikes: We have been seeing lots of shoot strikes caused by Peach twig borer or Oriental fruit moth. These shoot strikes are primarily a problem in first leaf orchards, where you’re encouraging shoot elongation to establish tree structure. Cut open shoots to see which pest is responsible. See pictures and management info on the UC IPM Website. Use pheromone traps to time control sprays, where needed.
- Nitrogen: If you are worried your orchard may be nitrogen deficient, consider taking early season leaf samples once leaves have reached full size, which is roughly 35-50 days after full bloom. Careful following of leaf sampling protocol will provide a good estimate of how summer leaf levels will look. Sampling protocol on page 14 of the Nitrogen Best Management Practices Handbook. April is also a key time for assessing how large the crop is, and adjusting the nitrogen fertilizer budget according. Excess N in the tree (measured by leaf samples) contributes to increasing hull rot incidence.
- Large Bugs: Monitor for large bugs (leaffooted bugs in March-April, stink bugs in May). Distinguish between the many causes of gummy nuts with the helpful guide in our article on the subject.