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Vera A. Krischik
Associate Professor |
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Mailing Address:
219 Hodson Hall, 1980 Folwell Ave.
University of Minnesota
St. Paul, MN 55108
Phone: 612-625-7044
E-mail: krisc001@umn.edu
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Education:
M.S. Department of Zoology, University of Maryland, College
Park, MD.
Ph.D. Department of Entomology, University of Maryland, College
Park, MD.
Academic Experience:
1994-present Assistant Professor, Department of Entomology,
University of Minnesota, St. Paul, MN.
1993-1994 Assistant Professor, Department of Biology, University
of Delaware, Newark, DE.
1991-1993 NSF Visiting Professor, Instit. of Ecosystem Studies,
NY Botanical Garden, Millbrook, NY.
1987-1991 USDA, IPM administrator for grain marketing.
1985-1991 Post Doc, Department of Entomology, University of
Maryland, College Park, MD. |
Research Interests:
My interests are to increase the use of IPM tactics, including
the use of scouting programs and the application of biorationals,
to reduce insect problems in the Twin Cities. Collaborations
with the Departments of Forest Resources, Horticulture, and
Landscape Architecture give me access to practitioners in the
field. Training of Master Gardeners, Urban Foresters, and involvement
in PAT (Pesticide Applicator Programs) provides needed educational
information on the methods and success of IPM programs. This
year I hosted an IPM workshop which was attended by over 85
interested landscapers, growers, consumers, and green industry
managers. I plan to continue the IPM workshop in Spring of 1998.
Plant stress and decline are a major problem for plant health
care in urban areas. My research identifies factors that make
plants susceptible to stress and cause increased insect damage.
One of my research projects is to compare the resistance of
street trees and trees in forests. It is not known whether changes
in plant resistance as a result of stress, or changes in predation
and parasitism rates, are responsible for insect outbreaks in
urban areas. It has been suggested that increased number of
predators and parasitoids in native habitats regulate insect
populations where as decreased natural enemies and increased
plant stress and mobilization of nitrogen, increase pest outbreaks
in urban areas.
My research evaluates the role of predation by generalist predators
in controlling elm leaf beetle populations in forested habitats
compared to shade trees. There are greater numbers of beetles
found on shade trees compared to forest trees. There are fewer
active ant colonies near shade trees. Elm leaf beetle is not
controlled by any parasitic insects, although some imported
parasitoids exist. Also, studied will be the effects of leaf
quality and suitability on insect populations. Leaf quality
is measured through nitrogen and defense chemical analysis.
Leaf suitability to insects is measured through bioassays. This
research will determine whether plant stress or fewer predators
and parasites in urban landscapes are responsible for insect
outbreaks in shade trees.
We began a research program on the control of elm leaf beetle
using Beauveria sprayed under the dripline of the tree
in the mulch. Most elm leaf beetle larvae fall from the canopy
and pupate as exopterate pupae in the mulch and grass under
the tree. Control on the mulch is sustaining and offers an easier
alternative to canopy spraying. Also studied, will be the level
of defoliation associated with reduction in shoot growth; effects
of applying control agents to the mulch on reducing beetle populations
below damaging thresholds (shoot elongation); levels of defoliation
associated with aesthetic threshold; and aesthetic threshold
modification before and after educational IPM programs.
Another research program is concerned with the effects of multiple
stresses on resistance to Populus deltoides (Eastern
cottonwood). By studying multiple stresses, it can be identified
what factors alter plant resistance. With this information,
hopefully new plant cultivars could be developed that are more
stress resistant. Resistance can be related to chemical factors
preventing herbivory, or alterations in shoot/root ratios. For
instance, greater investment by a plant in roots, rather than
shoots, can make the plant more resistant to herbivory since
reserves stored in roots can be mobilized to produce new leaves.
Young saplings of Eastern cottonwood were damaged in a number
of ways: mechanically (by cutting the leaves), natural insect
damage, pathogen damage, UVB damage, and ozone damage. The ability
of the cottonwood to induce or increase levels of defense chemicals
was studied. The results demonstrate that different types of
damage produce different chemical changes in the plants, which
shifts the palatability of the plants to insects. Most interestingly,
UVB dosages at 20% ozone depletion, induce (= increase) a different
set of chemicals than herbivory. These induced chemicals are
flavonoids. Flavonoids are nontoxic and are responsible for
some flower colors in plants. This shows that plants aren't
the simple creatures that we often think. They can clearly change
their chemical defense based on the type of damage. Upcoming
research with Cottonwood will investigate the effects of drought,
and root damage as plant stresses, on plant chemistry and insect
resistance.
Another project on controlling insects on woody ornamentals
is with the Como Conservatory evaluating the use of oils and
soaps on controlling 5 species of scale insects. We also evaluated
the effects of oils, soaps, and the fungus Beauveria bassiana
(two formulations) on natural enemies augmented for control
of scale insects and mealy bugs. We began an IPM program with
the Minnesota Zoo for their insect problems.
I also have been writing a manual for Minnesota on insects
associated with shade trees and turf. This is being accomplished
by scouting, trapping, and working with the landscapers and
growers. The book contains over 180 of the insects found in
urban landscapes in Minnesota. The manual contains pests of
trees and turf, their identification, scouting technique, management
tactics, and control options.
Research Projects:
- Effects of biorationals on scales and nontarget biological
control agents in conservatories.
- Effects of formulations of Beauveria on controlling
elm leaf beetle on foliage and in the mulch.
- Evaluation of population dynamics of herbivorous insects
in shade trees and forests.
Extension Projects:
- CUES resource center educational material production.
- Development of 15 educational videos into IPM scout training
course.
- Completion of "Manual on identification and IPM of
landscape plants and turf".
- IPM workshop.
Teaching Interests:
I plan to develop an IPM course for woody plants. Presently,
I provide lecutres on IPM for urban ecosystems for courses in
the Horticulture and Entomology Deparments. I teach in numerous
outreach activities. |
Selected Publications:
Krischik, V. A. and R. F. Denno. 1997. Population differences
in larval and adult adaptation of Trirhabda beetles to
composite hosts. Evolution. Submitted and under revision.
Findlay, S., M. Carreiro, V. Krischik, and C. G. Jones. 1996.
leaf damage affects leaf litter quality. Ecological Applications.
6(1):269-275.
Krischik, V. A. 1996. Sustainability in urban ecosystems. MES,
25 minute video.
Krischik, V. A. and K. Bevaqua. 1996. Sustainability in urban
ecosystems. MES bulletin.
Krischik, V. A. 1996. Butterfly gardening in Minnesota. MES
slide set and bulletin.
Krischik, V. A. 1995. What is IPM? Overstory. Minnesota
Bulletin of Community Forests.
Jones, C. G., R. F. Hopper, J. S. Coleman, and V. A. Krischik.
1993. Plant vascular architecture controls the distribution
of a systematically induced defense. Oecologia 93: 452-456.
Coleman, J. S., C. G. Jones, and V. A. Krischik. 1992. Phytocentric
and exploiter perspective on phytopathology. Advances in
Plant Pathology 8: 149-195.
Krischik, V. A., R. Goth and P. Barbosa. 1991. Generalized
plant defense: Effects on multiple species. Oecologia
85:562-571.
Krischik, V. A. 1991. Developments in grain insect policy and
detection. J. of Operative Millers. March: 5839-5842.
Books:
Krischik, V. A. and J. Davidson. 1997. IPM manual for landscape
plant pests, turf, and biological control agents. In progress.
Krischik, V. A. 1995. Women in Science: Career Trajectories
and Management Tactics for Women Scientists. Special Publication,
IES, NY Botanical Garden, Millbrook, NY.
Krischik, V. A., G. Cuperus, and D. Galliart (eds.). 1995 and
1992. Stored Product Management. Oklahoma State University
204 pp. 1st and 2nd editions.
Barbosa, P., V. A. Krischik, and C. G. Jones (eds.). 1991.
Microbial mediation of plant-herbivore interactions.
John Wiley and Sons, Inc. 530 pp.
Recent Presentations:
Krischik, V. A. 1996. Comparison of UVB and ozone effects on
plant induction and insect feeding. International Conference
of Entomology, Florence, Italy. |
Graduate Students:
Current:
Emory Matts, MS
Emily Tenzcar, MS
Former:
Scott Smith, MS
Marcus Zbinden MLS
Barbara Gregerson, MAG
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