April 2022 - 23

tank mix conditions can influence the
performance of several newer active
ingredients, and please pay special
attention to these details stated on the
product label. Successful incorporation
of these newer RR compounds into
more
diverse
insecticide
rotations
will benefit neonicotinoid resistance
management, but also emphasize
the importance of scouting for other
common pests which may influence
your choice of product to
achieve
control of both pests.
Flexible resistance
management
strategies that rotate chemistries in time
and space are critical to maintain the
efficacy of each individual pesticide used
in a production sequence - Insecticide
Resistance Action Committee (www.
irac-online.org). When successful,
growers can prolong the longevity
(duration of effective control) of useful
insecticides which, in turn, improves
profitability and minimizes the need
for additional insecticide inputs to
manage problematic populations.
Currently, potato growers have access
to many MoA groups, delivery methods
and formulations of insecticides to
control CPB; but continue to use atplant
neonicotinoids for the control of
other sucking insect pests in addition to
the CPB. Incorporation of newer MoA
groups into a long-term, CPB resistance
management program will reduce
selection pressure for resistance to any
one of these new MoA groups.
The following suggestions assume a
two-generation, CPB lifecycle common
to many potato production regions of the
temperate Midwestern U.S. (Figure 1).
The growing season has been subdivided
into three specific treatment windows,
early generation, late generation,
and spring trap crop (i.e., reducing
populations of colonizing adults).
In regions where only a single
generation occurs each year, growers
may only need to use one MoA group
applied early in the season for adequate
control of larvae. Remember, nearly all
of the compounds included have the
greatest activity on small larvae (first
and second instars). However, one
compound - novaluron, IRAC group
15, benzoylureas - has effects on several
life stages including molting disruption
Spudman * April 2022
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in small larvae, reduced female fertility
and reduced viability of eggs that have
not hatched. Growers will achieve the
greatest control using novaluron during
the early generation window when
synchronous egg deposition occurs and
larval life stages are the most uniform in
the crop.
Multiple-season, CPB management
plans are designed to limit exposure
to MoA groups over consecutive
generations (Figure 2). Here, populations
are exposed to a given MoA group once
every three to six generations.
Decisions on specific programs
should be based on a reasonable
estimate of neonicotinoid insensitivity
observed or measured in commercial
fields. Presented are several different
scenarios that are adapted to potato
maturity, choice of application
approach and the degree of field-level
neonicotinoid insensitivity.
- Russell L. Groves, Ph.D., is a professor,
Extension specialist and department chair
of the University of Wisconsin-Madison's
Department of Entomology.
http://www.irac-online.org
April 2022

Table of Contents for the Digital Edition of April 2022
