2018 Almond Bloom Considerations

An almond tree nearing bloom taken on February 6th, 2018.

2018 almond bloom is around the corner. This year will probably be one of the earliest almond blooms we have had in Merced County. This accelerated bloom is due to the warmer, sunny weather experienced through January. Depending on conditions following flowering, hull-split and harvest should also be earlier.

Weather for the coming bloom period looks to be favorable for the San Joaquin Valley. Warm conditions (temperatures in the 70’s) and no rain in the forecast provides the conditions that are conducive for rapid flower development. Thankfully, these conditions will not favor disease. Early bloom sprays may not be needed for many tolerant varieties (e.g. Nonpareil), unless heavy dew and susceptible varieties (i.e. Butte) are present.

Regardless of weather, a fungicide spray made at full bloom/petal fall should be considered. This fungicide should provide protection for brown rot, shot-hole and jacket rot. Of these three, jacket rot is one of the harder fungi to control with the modern fungicide chemistries as the strobilurins (FRAC 11) and DMIs (FRAC 3) are not effective. This spray timing will provide protection for any rain events that would occur within two weeks of application. Successive in-season sprays may be needed if the weather turns wet. Further information reagrding fungicide timing and efficacy can be found here: http://ipm.ucanr.edu/PDF/PMG/fungicideefficacytiming.pdf .

Fungicide applications should be made at a time of day to reduce bee exposure. Applications later in the day will reduce exposure as bee foraging is decreased in the afternoon. If applying at night, allow enough time for the fungicide dry before bee foraging begins the next day. Also, avoid any addition of surfactants with the fungicide unless directed by the fungicide label. Many more management practices for bees can be found at The Almond Board of California’s website: http://www.almonds.com/pollination .

The first irrigation will be tricky to time in 2018. The lack of winter rainfall has reduced the amount of moisture in the soil profile. This will be further compounded by the earlier development of the tree, leading to an increase in early season water use in comparison to previous years. Use of the pressure chamber or soil moisture probes should be utilized to determine when to begin irrigation. Irrigating now to attempt to refill the soil profile is not advised as it may create anaerobic conditions within the root-zone during the critical time of bloom.

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