36 Almond Facts
SEPTEMBER | OCTOBER 2014
WM-AlmondFacts1/2v.indd 1
8/28/13 5:44 AM
nematodes (usually ring) and PRD
are severely stunted and fail to
be highly productive. These soils
should be fumigated with either
a broadcast Telone-II treatment
or a rowstripped Telone-II C35.
These treatments are expensive,
but multiple trials have found that
fumigated trees have produced
nearly double the non-fumigated
control within the frst three years
of harvest (third through ffth leaf),
which more than compensates for
the upfront fumigant expenses.
Considerations
for Established
Orchards
Within established orchards, the
options for managing nematode
and PRD are more limited.
Dr. Michael McKenry, UC
Nematologist emeritus, has found
that Spirotetramat (Movento®) can
reduce populations of nematodes in
almonds and walnuts. Observations
from within the feld have been
favorable. Bayer CropScience, the
manufacturer, suggests applying
this product as a foliar spray in the
spring and fall on blocks severely
impacted by nematodes.
Because the product is applied
to the leaves but operates against
pests in the roots, it is critical to
mix Movento® with a penetrating
adjuvant so that it is absorbed
by the leaves, where it will be
translocated via the phloem down
to the roots. Similarly, spring and
fall sprays should be applied when
there is adequate canopy cover.
Other products are also available or
in development, and feld tests are
underway. Hopefully, we will have
more products in the near future.
For PRD, there aren't any chemical
options for control. Proper irrigation
management and spoon-feeding
of nutrients may be of beneft.
Work by Dr. Bruce Lampinen and
colleagues found that trees within
PRD-affected felds are often over-
irrigated, which stunts growth.
Trees need to be irrigated to match the water demand, which means smaller trees
will require less water than larger trees. Since the root system is affected, very small
amounts of fertilizer applied frequently may help increase growth. Studies have
shown that small trees require less nitrogen than what is usually applied (~25-30
pounds per acre) for the growing season, if applied to the root system of the tree.
PRD and nematodes are best managed with pre-plant actions. Schedule and take
the proper amount of time to remove and prepare the orchard prior to fumigation.
If the timing of harvest or other factors prevents the ability to properly prepare the
orchard as I’ve described, it may be best to delay planting considering that a new
orchard is a 25-year investment and commitment.