WCN Dec e

Many growers like to wait for dew,
dense fog or some rain before they
shake mummies in the winter (photo by
V. Boyd.)
At least a few growers in the northern Sacramento Valley have put tracks on their
shakers so they can remove mummies even in wet orchards (photo by F. Niederholzer)
who also is manager of the Nickels Soil
Lab.
“Over the past two years at Nickels,
we’ve had some of the best control measures
of the last 10 years,” he said.
Hung in orchards in the spring,
pheromone dispensers emit chemicals
throughout the season that imitate those
produced by female NOW. This confuses
male moths, preventing them from
finding females with which to mate. The
system works best on large, contiguous
blocks, but Haviland said even smaller-scale
growers have seen benefits.
“We know it works on 40 acres in
almonds,” he said. “We know it works
better on 100 acres, and anything over
100 is just bonus.”
While not a silver bullet, mating disruption
can help eliminate at least one
in-season NOW treatment, according to
UCCE.
Hull Split Sprays
Although insecticides are part of
NOW IPM, they alone may only be 50%
effective, and in many cases, less, Rijal
said.
“Every time I do a trial with insecticides,
I never reduce damage to zero
even though I dip the nuts in a solution,”
he said. In other words, insecticides at
hull split are critical, but they cannot
solve all of the problems and need to be
combined with other control measures.
Insecticide choice also has grown
more challenging as NOW has become
less sensitive to the pyrethroid class of
chemistries, Haviland said.
“Generally, pyrethroids are not
working as well as they used to; there’s
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