IN YOUR ORCHARD
TIME TO CONSIDER
As with every year, harvest will be challenging in 2018. The long bloom period experience in February and March of
this year will lead to prolonged period of hull-split and ripening, creating issues with shake timing and insect infestation.
Initiation of hull-split was closer to “normal” this year. If temperatures stay hot, the rate of navel orangeworm (NOW)
development will increase, leading to another year with high mid-to-late season NOW populations.
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 (ETc) 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.
Excessive moisture, however, can delay harvest and
increase the incidence of hull rot. As the shake timing
approaches, reduce the duration of the irrigation to
reach the desired stress level. Time the last irrigation
to be a few days prior to shaking. Once the trees are
shaken, do what is possible to apply full irrigation so
trees are not stressed during the postharvest period.
Harvest Timing
Timing of harvest is always tricky. Trees should be
shaken as soon as a few test trees shake clean. Be
careful of 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.
Growers must balance between harvesting early
and having a longer dry time on the ground and a
greater chance of ant damage or harvesting later
and having a greater chance of NOW. In years in
which NOW pressure is greater than normal — such
as this year — an earlier timed harvest should be
considered. An earlier harvest reduces exposure time
to NOW and depending on flight timing, may be more
effective than insecticide sprays. Work to manage
any fire ant or pavement ant populations prior to
harvest that may feed on the nuts so that trees can
be shaken as soon as possible. If baiting wasn’t done
in June, then consider baiting in July with Methoprene
(Extinguish
®
) or as close to harvest as possible with
Metaflumizone (Altrevin
®
). Once the nuts are on the
ground, windrowing and pickup should occur in a
timely process to reduce both NOW and ant damage.
Harvest Sample
Taking a harvest sample is simple, but time consuming.
It should be considered because the amount of insect
Shaker damage can lead to Ceratocystis infections of the
damaged area of the tree. As this fungus grows, it can girdle
trunks or scaffolds, leading to limb or tree loss. Proper shake
timing and irrigation management can reduce the occurrence of
bark damage, adding years of life to the orchard.
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A L M O N D F A C T S
