Spudman April 2023 - 29

against the Colorado potato beetle.
Fitness of the insect was measured
in relationship of its biological
characteristics of weight, developmental
time and general fitness.
Three products were tested: SA-type
(Actigard 50WG), JA-type (Blush 2x),
and an elicitor with both SA and JA
activity (Regalia); water was used as a
control. Plants were sprayed at either
the leaf development or flowering stage
to assess how plant phenology affects
plant-insect responses.
One day after treatment application,
plants were infested with five Colorado
potato beetle larvae. Preliminary data
suggest that elicitors, particularly those
that induce a JA-dependent response,
can lower larval fitness, and therefore a
reduction in defoliation was observed.
This study only used a single potato
variety but could potentially be
expanded into including other varieties,
because each may respond differently
to insect feeding based on chemical
composition, trichomes and other
factors that we plan to investigate.
The student is also looking into
evaluating the force which an insect
like the Colorado potato beetle uses to
shear leaves. This is a study developed
to reinforce the plants' constitutive
defenses against this pest.
This article intends to briefly
Figure 3: Damage
caused by the Colorado
potato beetle.
introduce the reader to a new concept:
elicitors and how these chemical
Figure 2: The Colorado potato beetle.
plants or can be synthesized for optimal
configuration and applied as sort of a
" vaccination " to a plant.
Synthetic elicitors have been studied
with mixed results in many cultivated
crops including cranberries and other
small fruits. To our knowledge, they have
not been well documented in potatoes,
especially from the applied perspective.
The challenge for applied studies
of elicitors is the complex interaction
between the signal that the plant receives
from the elicitor and all the other signals
the plant receives from external outputs.
In general terms, the JA and ethylene
pathways are associated with chewing
insects and necrotrophic pathogens,
while the SA pathway is associated with
piercing/sucking insects.
In field conditions where the plant
is exposed to both pathogen as well
as effectors from the insect and their
microbial endosymbionts, the action and
efficacy of a synthetic elicitor is highly
variable. An understanding of this " cross
talk " is needed (meaning more research)
among all components of the system.
BASELINE INFORMATION
In 2021 and 2022, as part of a student
research project, we conducted a series
of bioassays and greenhouse trials
to evaluate the efficacy of synthetic
elicitors to protect Russet Burbank
components could help protect crops
while reducing the development of
pesticide resistance. Elicitors could also
provide some evidence of their efficacy
while highlighting the challenges
associated with incorporating elicitors
into an integrated pest management
program. It is our hope that this
article will pique curiosity and foster
more investigation that could
provide research-based information
into another tool in our current
management programs for potatoes.
Silvia I. Rondon is a professor and
the director of the Oregon IPM Center,
Crop and Soil Sciences at Oregon State
University, silvia.rondon@oregonstate.edu.
Alexander Butcher is a master student at
the Oregon State University, Oregon IPM
Center, Crop and Soil Sciences, alexander.
butcher@oregonstate.edu.
Spudman.com 29
http://www.Spudman.com
Spudman April 2023

Table of Contents for the Digital Edition of Spudman April 2023
