TIME TO CONSIDER
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Almond Facts
MAY | JUNE 2016
Treatment for other diseases such as anthracnose and
scab are not effective at this time. These applications
should have occurred earlier in the season to reduce
populations. Applying material now for these diseases
may help with sleep, but will provide no reduction of
crop loss or leaf drop.
Keep an eye out for bacterial spot. This relatively new
disease has been affecting almond orchards. Symptoms
include amber gumming from nuts, with a lesion about
one-quarter inch in diameter that could extend to the
shell, and small, pinhole sized lesions on leaves with a
yellow halo. It severely affects ‘Fritz’ and ‘Padre’ with
infections on other varieties found. Treatments will have to
be planned for the dormant and spring of 2017 to manage
this disease.
Hull-Rot Management
Hull rot is a fungal infection of the splitting hull by either
Rhizopus stolonifer or Monilinia spp. Toxins produced
by these fungi move into the tree, killing spurs and
wood within the canopy, impacting future production.
Trees that are over-fertilized and over-irrigated tend to
have increased hull-rot. Nitrogen applications should be
minimized after kernel fill and, if possible, RDI should
be applied. Fungicides have been shown to be effective in
reducing strikes by Rhizopus, but must be timed to the
initial splitting of the almond hull. This usually coincides
with NOW sprays. Hull split fungicide sprays do not
reduce hull rot by Monilinia spp. Data indicates that
fungicides for Monilinia need to be applied in early- to
mid-June to reduce latent infections of the hull. Fungicides
when used without RDI and nitrogen management
practices have generally shown a reduction of 10 to 25
percent of hull rot infections, and highlights the value of
an integrated program.
Managing Navel
Orangeworm
If navel orangeworm (NOW) populations are high,
hull-split sprays should be made to protect the crop
from infestation. Sprays should be made at the onset of
hull-split (e.g. 1 to 5 percent). Often at this time, blanks
