TIME TO CONSIDER
34
Almond Facts
JULY | AUGUST 2016
Time To Consider
DAVID DOLL, UCCE Nut Crop Pomology Farm Advisor, Merced County
Harvest has arrived earlier than “normal”
this year, albeit not as early as expected. This
shortened season is due to the early bloom,
warmer than normal temperatures following
bloom, and, in some cases, reduced water
applications.
Irrigation Management
With the exception of drying down the orchard for
harvest practices, irrigation during the period of hull-split
to harvest should be as close to full evapotranspiration
(ET
c
) as possible. Kernel weight is still accumulating and
continues until the abscission layer between the peduncle
and hull forms. Adequate (but not excessive) moisture must
be available through hull-split, as hulls must be turgid
to properly split. Water stress can change the onset of
hull-split and ripening, cause stick-tights, reduce kernel
weights, and cause shriveling or “texturing.” Excessive
moisture, however, can delay harvest and increase the
incidence of hull rot.
Harvest Timing
Timing of harvest is always tricky. Growers must balance
between harvesting early and having a longer dry time
on the ground, or harvesting later and having a greater
chance of navel orangeworm infestation (NOW). Growers
wanting to produce inshell Nonpareil must allow the crop
to dry longer in the tree in order to produce the greatest
proportion of inshell product. However, in years in which
NOW pressure is greater than normal- such as this year
- an earlier timed harvest should be considered. Trees
should be shaken as soon as a few test trees shake clean.
Be careful on shaking too green, as longer shaking time
per tree can damage tree trunks. This “barking” of trees
often creates wounds that are susceptible to fungal wood
pathogens such as Ceratocystis. Once the nuts are on the
ground, windrowing and pickup should occur in a timely
process to reduce ant damage.
Harvest Sample
Taking a harvest sample is simple, but time consuming.
Nevertheless, it should be considered because the amount
of insect damage can be masked by the handling that
occurs during sweeping, pickup, and processing. Our trial
data has found that as much as 4 percent more damage
can be found in harvest samples than what was indicated
in the processor report. In other words, when we found
an estimated 5 percent damage/reject level in the harvest
sample, the processor indicated a 1 percent rejection level.
The 4 percent discrepancy is most likely due to damaged
nuts lost during the harvesting process (i.e. sweeping, pick-
up, and removed during hulling and/or shelling). This is
still lost crop even though it isn’t detected.
Another reason for performing a harvest sample is to
identify the type of damage that does occur in the field.
For example, ant damage often does not show up in the
final grade because the chewed kernels are often blown
out the back of the pick-up machine and are not present
in the delivery sample taken at the receiving station.
Gummy nuts due to nutrient deficiencies, feeding damage,
or other conditions are also lumped together as rejects on
grower statements. Growers should consider requesting
a breakdown of the causes of the reject damage in their
deliveries by contacting their huller/sheller or
Blue Diamond
Field Supervisor. That information will then be printed
Severe water stress between hull-split and harvest can cause a
reduction in kernel weights and “textured” almonds.
