Mar_Apr_PCC_2017_Web

MATING DISRUPTION
Photo Credit: Kathy Keatley Garvey
how mating disruption effects the
ability to monitor pests in orchards
under MD as well as in orchards in
proximity to MD blocks. In orchards
where MD tactics are being used,
pheromone-only monitoring methods
will certainly be impacted. It
is becoming increasingly apparent
that traps in orchards near but not
within MD blocks can be effected as
well. In most cases, this is occurring
without the added benefit of substantial
disruption, and thus population
and damage reduction. Researchers
are currently investigating just how
far-reaching the impacts of mating
disruption are to nearby non-MD
blocks.
Disruption of sexual communication
in moths is thought to function
by the following broad types of
behavioral mechanisms:
• Competitive attraction
(false-plume-following), in
which males are diverted from
orienting to females because they
are attracted to competing ‘false’
trails emitted by synthetic pheromone
dispensers.
• Non-competitive mechanisms,
whereby exposure to synthetic
pheromone inhibits or blocks the
ability of males to sense and/or
respond normally to pheromone
emitted from females. These include
camouflage, desensitization
(i.e., adaptation and habituation),
and sensory imbalance.
• Combinations of these mechanisms.
Navel orangeworm larva.
Trapping In and Near Mating
Disruption Orchards
Emily J. Symmes
UCCE IPM Advisor,
Sacramento Valley
Mating disruption options have
improved in recent years,
and orchards under mating disruption
(MD) for certain key pests are
becoming increasingly common. In
particular, this article focuses on the
effects of MD on trap-based monitoring
of codling moth (CM) and
navel orangeworm (NOW). With
regard to codling moth, this can
apply to walnuts, apples, and other
pome fruits. For NOW, this information
largely applies to almonds and
pistachios.
It is important to understand
Page 32 Progressive Crop Consultant March/April 2017
While understanding the mechanism(s)
underlying successful mating
disruption is important to the development
of products and best practices
to maximize the effectiveness of
this technology, one thing becomes
clear in a practical sense—the presence
of synthetic pheromone in and
around the orchard environment,
if effectively impacting mate location/mating
success, will necessarily
impact our surveillance methods. In
particular, our ability to track population
abundance and activity using
pheromone lures. Fortunately, there
are solutions to this problem in the
form of alternative lures for trapping,
albeit many pest control and crop advisers
have less experience with these
than the historical pheromone-only
lure standards.
For the two pests this article is
focused on, CM and NOW, sex pheromones
are emitted by females and
elicit responses from males of the
species. That means, with the exception
of very low to negligible random
catches of females, pheromone traps
will predominantly track only male
activity. One of the goals and indicators
of successful MD for NOW and
CM is trap shutdown (zero to very
low male catches in pheromone traps
relative to non-MD environments).
If you are working in a MD environment,
you certainly want to monitor
pheromone-only traps so that