44 Almond Facts
JANUARY | FEBRUARY 2015
Time To Consider
David Doll
Delayed Dormant Pest Control
The dormant period provides an opportunity to control various insects and
diseases. If increased scale and mite populations are seen on a sampling of spurs
or were observed in 2014, a treatment may be warranted. Low to moderate
populations of these pests can be controlled by an application of 6 to 8 gallons
of dormant oil, while moderate to high populations will need a combination
of oil and an insecticide. If tree defoliation occurred in 2014 from fungal
scab, the addition of either copper or chlorothalonil will reduce scale and mite
populations, and will delay or prevent the disease from occurring in 2015. Please
note that chlorothalonil and oil are phytotoxic to fowers and green tissues. If
peach twig borer has been observed, the addition of
Bacillus thuringiensis
(Bt) as
well as many other insecticides may be used for control in combination with the
I hope you all had a wonderful holiday season and a great start to the New Year. Although we like to think
this is a "quiet" time of year, I often fnd operations busy trying to wrap up many of the dormant season
activities in preparation for bloom.
oil. More information on these pests
and control can be found at ucipm.
ucdavis.edu.
Protecting the Crop
from Bloom and
Spring Diseases
Almond blossoms and newly emerged
leaves are sensitive to several different
diseases. These diseases include brown
rot, shot-hole, anthracnose, jacket
rot/green fruit rot and leaf blight. All
are more severe in wet weather when
long periods of leaf-wetness occur.
Although we tend to focus on diseases
at bloom, infections can occur in mild
and wet conditions after bloom. Dew
may also create conditions conducive
for disease.
To prevent these diseases from
occurring, most make use of
fungicides. Fungicides work best as
protectants, and need to be applied
prior to infection. Coverage from a
fungicide spray will last around two
weeks, unless signifcant rainfall occurs.
In dry weather, a single application at
full bloom or petal fall will usually be
effective (i.e. full bloom 'Aldrich,' petal
fall 'Nonpareil'). If applying prior to a
rain event, applications will need a few
hours to dry to prevent "run-off." In
rainy weather, follow-up sprays will be
needed every 7-10 days. Some varieties
— such as 'Butte' and 'Carmel' — are
more susceptible to disease and may
require a spray even in dry weather,
while others, such as 'Nonpareil,' are
quite tolerant and may not need a
bloom spray. Orchard history, weather
and your comfort level should be the
guidance in determining your bloom
and springtime disease control strategy.
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