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GRASSHOPPER
ECOLOGY & MANAGEMENT
Rationale: Grasshoppers play an important role in North American
grassland ecosystems, serving as food for wildlife and contributing to
nutrient cycling. However, periodic grasshopper outbreaks on rangeland
can result in competition with other herbivores for vegetation and lead
to grasshopper dispersal into crops. Of the 400 species of grasshoppers
in the Western United States, fewer than 2 dozen are capable of causing
significant economic damage to crops and forage. In the past, pesticide
application has been the main tool used to combat grasshopper outbreaks
on rangeland. Due to increased environmental concerns and economic costs
associated with pesticide use, we are currently investigating
ecologically-based approaches to grasshopper management. Very little
research has examined preventative strategies that reduce the likelihood
or intensity of grasshopper outbreaks. Developing ways to prevent
grasshopper outbreaks requires that we understand the ecological
interactions underlying these outbreaks and can manipulate them
accordingly. Certain types of grazing or habitat management may create
unfavorable habitats for grasshoppers or spur increases in naturally
occurring grasshopper diseases and predators. In addition, microbial
products may provide environmentally-benign management options when
warranted.
 
Contributing Scientists:
David Branson,
Stephan Jaronski &
Greg Sword
Goal:
 To understand the
ecological processes underlying grasshopper outbreaks.
To develop sustainable and affordable grasshopper management that
incorporates ecological processes to reduce grasshopper outbreaks, while
improving or maintaining the condition of rangeland.
To evaluate new
microbial controls and new technologies for existing microbial agents to
manage grasshopper outbreaks.
For more information:
 Grasshoppers:
Their Biology, Identification and Management (Comprehensive web site)
Homing In on Hopper Hordes
Grasshopper
Management CD Request Form
U.S.
Rangeland Grasshopper Collection
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MORMON CRICKET
ECOLOGY
Rationale: Outbreaks of the Mormon cricket, Anabrus simplex
(Orthoptera; Tettigoniidae), once again threaten large parts of the
western US. Mormon cricket outbreaks originate on rangeland and can lead
to the formation of huge migratory bands that move into and damage crop
systems. At NPARL scientists are working as part of an international
collaborative effort to examine Mormon cricket migratory behavior as a
means to ultimately predict migratory band movement patterns. Predictive
models of migratory band movement will help to
 fine-tune
existing management practices, thereby reducing the cost, manpower, and
undesirable non-target effects associated with chemical control
operations. This work also serves as an important component of a broader
research endeavor to understand the generality of behavioral mechanisms
underlying collective movement in other animal groups such as migratory
locusts.
Mormon cricket movement is being investigated at three different spatial
scales using a combination of laboratory and field experiments. The
results of multiple analyses conducted across spatial scales will be
integrated to generate models of group movement patterns at the
landscape scale. Laboratory analyses are being conducted using a
computer-based video tracking system to quantify individual movement
behaviors and their interactions with other insects. Intermediate scale
analyses are planned using a related video analysis technique to
simultaneously quantify the movement and social interactions of hundreds
of individuals simultaneously as they march in naturally-occurring
bands. At the landscape scale, radiotelemetry is being employed to track
the long distance movements of individual Mormon crickets as they travel
in within bands. Movement data from the field are then correlated with
local topographic and weather variables to identify environmental cues
that affect the direction, distance and speed of migratory band
movement. These results, in conjunction with knowledge of the behavioral
mechanisms underlying band formation and movement, will be used to
develop models of band movement.
Contributing Scientists:
Greg Sword
Collaborators: Pat Lorch
(University of North Carolina, Chapel Hill), Darryl Gwynne (University
of Toronto at Mississauga), Stephen Simpson (University of Oxford), Iain
Couzin (University of Oxford/Princeton) and David Sumpter (University of
Oxford).
Goals:
To determine if Mormon crickets expresses locust-like density-dependent
phase polyphenism.
To understand the environmental cues that mediate Mormon cricket
migratory band formation and movement patterns.
To develop predictive models of Mormon cricket migratory band movement.
For more information:
Grasshoppers: Mormon Cricket
Radio
Tracks Crickets
Dinosaur
Monument Study May Help Stop Mormon Cricket
Scourge
BBC News: Utah hopping mad over crickets
Plague of crickets does $25M Damage to Utah crops
Tiny
Transmitters Guage Cricket Movements
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WHEAT STEM SAWFLY BIOLOGICAL CONTROL
Rationale: The wheat stem sawfly, Cephus cinctus (Hym.:
Cephidae), has been the most important and consistent pest of wheat in
the northern Great Plains since large-scale cereal crop cultivation began more than 100 years ago.
Field infestations of
 70
to 80% have been recorded at several locations and in several years.
Yield losses are the result of larval feeding which can reduce grain
weight by more than 20%, and fallen grain due to stem cutting. Yield
losses of up to 35% have been reported in some locations, and across the
region, annual losses to wheat and other cereal crops can exceed US $100
million.
Current management practices are limited to
using resistant wheat cultivars or various tillage operations to destroy
sawfly larvae or pupae in the stubble. Several resistant cultivars have
been developed and released over the past 10 years. These cultivars have
solid stems filled with pith, and suffer less damage when sawfly numbers
are high. Unfortunately they often yield less or have lower protein
content than hollow-stemmed cultivars. Spring or fall tillage may also
reduce populations of wheat stem sawfly, though this management practice
requires additional field operations, increases production costs, and
may increase soil erosion rates. Pesticides are generally too costly and
largely ineffective because the larvae are protected within the stem..
Another important approach to managing pests is biological control.
Several native parasites attack the wheat stem sawfly in the Great
Plains, though they are usually not effective in preventing damage. At
the Northern Plains Agricultural Research Laboratory in Sidney, the
possibility of finding and utilizing natural enemies of the wheat stem
sawfly is currently being investigated.
Contributing Scientist:
Tom Shanower
Goals:
To find, import, evaluate and release safe and effective natural enemies
for the control of the wheat stem sawfly in North America.
Use molecular and conventional morphological characteristics to
understand relationships among sawfly species.
Characterize the impact of endemic natural enemies on sawfly population
dynamics.
Provide information to producers and other customers on sawflies and
other emerging pests in the northern Great Plains.
For more information:
Cutting through Wheat Stem Sawfly Dilemmas
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SUGAR BEET ROOT
MAGGOT BIOLOGICAL CONTROL
Rationale:
The Sugar beet Root
Maggot (Tetanops myopaeformis) is considered the most important
 insect
pest of sugar beets in the U.S., affecting production on more than
1,250,000 acres. Yield losses of 20-40% are common where insecticides
are not used for control. The primary control method for these insects are
planting-time insecticides. Most are highly toxic, restricted-use
compounds; continued use of these few insecticides is also likely to
lead to resistance. Alternative, biologically based and environmentally
benign strategies are needed. Entomopathogenic fungi such as
Beauveria bassiana and Metarhizium anisopliae have
been developed as microbial insecticides for other insect in the U.S.
and other countries. Isolates of either of these two fungi could serve
as the insect control component of a broader IPM system that also
incorporates microorganisms to control sugar beet pathogens, biorational
materials, such as Tagetes biomass, resistant/tolerant beet hybrids, and
induced systemic response.
Contributing Scientists:
Stefan
Jaronski
Goal:
Select at
least three candidate Beauveria bassiana or Metarhizium
anisopliae for further development using the commercial criteria of
spore production, shelf-life, and infectivity / virulence for the target
insect as well as secondary pests, such as wireworm.
Assess
persistence and efficacy of the candidate fungi in a range of soil types
representative of sugar beet growing areas, as affected by moisture, pH,
cation exchange capacity, nitrogen levels, organic matter, microbial
flora, sugar beet fungicide and herbicide residues. Determine the effects
of Montana State University microbial agents, under development for
plant pathogen control, on efficacy and persistence of the insect
pathogenic fungi.
Determine if
Induced Systemic Response impacts sugar beet root maggot damage and/or
has an adverse effect on the insect. Evaluate the tri-trophic
interaction among the sugar beet ISR, the insect and entomopathogenic
fungi.
Implement and
test a biologically based IPM system under commercial field conditions
to control SBRM, seedling diseases, Rhizoctonia Crown Rot and Cercospora
Leaf Spot, in cooperation with plant pathologists at Montana State
University and entomologists at North Dakota State University.
For more information:
Sugar beets
and Beet Sugar
Sugar beet
Root Maggot Management
Sugar beet
Research and Educational Board Homepage
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elcome to the Pest Management Research
Unit. Listed below are the unit's two research emphases including Weed
Biological Control and Insect Management. Simply click on the
research topics under each emphasis for additional information.
lso,
below is a list of the scientists and their technicians for Pest
Management Research Unit. By clicking on a name you can view their
information about that individual's current research, education
and experience. 
Biological Science Technician
impact the American farmer and rancher through
reduced profitability and increased input costs due to increased use of chemical controls. These costs reduce producer profits
and US competitiveness in national and international markets. Noxious
weeds can reduce biodiversity and quality of wildlife habitat on range and
in natural resource areas. A study of leafy spurge
estimated the total economic impact of this weed in North Dakota, South Dakota,
Montana and Wyoming at $144 million in 1995. The total impact of another
exotic, spotted knapweed, was estimated at $40 million in Montana alone.
The USDI-Bureau of Land Management estimates 19 million acres of land
under their management will be infested with weeds by the year 2000.
Biological control—an ecologically sensitive strategy using insects,
mites, plant pathogens and nematodes—is the foundation of integrated
exotic weed management. In addition to the ecological benefits,
biological control will reduce producer expenditures on chemicals. ARS
research in biological control is critical because of the widespread
ecological and economic impact these weeds have on American agriculture.
