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CENTER FOR ECONOMIC ENTOMOLOGY

Public Service

Illinois is constantly threatened by the appearance of new insect pests as well as changes in the behavior of existing pests that produce new and different problems. Center entomologists often are required to address these issues in a timely manner. The Center provides many educational programs and opportunities, in cooperation with the University's Experiment Station and Cooperative Extension Service, to give the public up-to-date information on the management of insect pests of agricultural, horticultural, forest, and urban environments, and on the control of mosquitoes and other medically important arthropods. One major component of the Center's programs is finding novel ways to combat pest problems while reducing environmental and health risks associated with the use of insecticides.

Center extension affiliates, in cooperation with Survey entomologists and other university specialists, produce newsletters that provide the agricultural community with information related to current and emerging crop and livestock pests. Also, these affiliates give homeowners and landscape professionals up-to-date management techniques for home and garden pests.

Another important service of the Center is its series of educational programs. Insect Theatre is an innovative, audience-participation series of plays and skits that teach young audiences about insects and biodiversity. For more mature audiences, Center staff teach a variety of workshops and short courses, and make numerous presentations to the public at museums, public and private organizations, Insect Expo, and the Open House and Agronomy Day of the College of Agricultural, Consumer and Environmental Sciences. In addition, Center staff present their research findings at professional scientific meetings.

Center scientists and affiliates continue to provide national leadership in entomology. Center members have been appointed to editorial boards of prestigious scientific journals, hold elected positions within the Entomological Society of America and the American Mosquito Control Association, and serve as representatives to numerous North Central Regional Research Committees and U. S. Department of Agriculture planning committees at the national level. Staff expertise is often called upon for manuscript and grant review for the National Science Foundation, U.S. Department of Agriculture, U.S. Forest Service, and the Cooperative States Research, Extension and Education Service.

Each year, Center scientists and extension specialists, cooperating with scientists in the Center for Biodiversity, perform a time-consuming but much needed public service--the identification of insects and other arthropods for individuals and for a variety of entomological projects. Economically important insect pests and potential pests must, for obvious reasons, be identified accurately. The Survey has one of the largest and most important insect collections in the U.S. These collections--and the Survey's scientists who identify and classify insects--are invaluable. Center scientists also coordinate statewide surveys for the occurrence and distribution of new exotic pests.

Special Recognition

Members of the Center for Economic Entomology strive for excellence in all aspects of their work. Recognition for special professional achievement is often granted by peers. Dr. Robert Novak served as President of the American Mosquito Control Association, Dr. Kevin Steffey is currently President of the North Central Branch of the Entomological Society of America, and Drs. Michael Gray and Richard Weinzierl are members of that branch's Executive Committee. Expertise is often recognized by appointed or elected positions on special committees. Drs. Cathy Eastman, Michael Irwin, Eli Levine, William Ruesink, Joel Siegel, Leellen Solter, Richard Weinzierl, Robert Wiedenmann, and many of the Center's support staff hold appointments in various national organizations.

Excellence in research is often recognized by successfully obtaining competitive grants from external funding agencies. Center staff have been awarded grants from the National Science Foundation, Consortium for Food and Agricultural Research, Illinois Soybean Program Operating Board, U.S. Army Corps of Engineers, and various agencies within the U.S. Department of Agriculture. Several state, county, and municipal agencies and the agribusiness community have provided resources to support our programs. Support of this nature is vital to the continuation of the Center's research and outreach activities in fundamental and applied entomology.

Pest Management

Activity of soy oils on nontarget organisms
P. Lewis, R. Novak, R. Lampman
Formulations of methylated soy oil have potential use as control agents for mosquito larvae and greenhouse pests. The potential impact of these products on nontarget organisms (both plants and animals) needs assessment. Laboratory tests determined toxicity of methylated soy oil on plants (tomato, squash, corn, turnips, and soybeans) and to water fleas (Daphnia pulex) and aphids. Methylated soy oil applied to plant leaves in amounts comparable to recommended rates of commercial products revealed no toxicity. Slight toxicity was seen in water fleas exposed to methylated soy oil and aphids reproduced at reduced rates on host plants treated with a methylated soy oil spray.

Strip tillage in cover crop mulches
C. Eastman, J. Masiunas, H. Bottenberg (University of Illinois)
In 1996, strip tillage was evaluated to improve performance of vegetables grown in cover crop mulches. Snap beans planted in spring-tilled strips created in rye mulch were compared with those grown in solid rye mulch or with conventional tillage. Crop growth and yield, as well as populations of pests such as potato leafhoppers, were monitored. Bean yields were higher in strip tillage than in solid rye mulch but were not equal to those with conventional tillage. Insecticide use and extra nitrogen did not improve yields, indicating that additional research is needed to improve crop performance in mulch systems.

Host plant resistance in soybeans
C. Helm, R. Nelson (U.S. Department of Agriculture), G. Brown-Guedira (University of Illinois)
Scientists from the Survey, University of Illinois, and U.S. Department of Agriculture Soybean Germplasm Collection are evaluating recently acquired soybean lines from China for a variety of traits that could be used directly to improve midwestern soybean varieties. The emphasis of the research is identifying new sources of resistance to leaf-feeding insects and incorporating this trait into high-yielding varieties suitable for use by Illinois growers. Another goal of this research is to develop a system of genetic markers that could dramatically streamline the time-consuming field and laboratory assays employed to detect usable levels of insect resistance.

Insecticide evaluation of crops
J. Shaw, M. Gray, K. Steffey, R. Weinzierl
Field trials were conducted to provide an impartial evaluation of chemical and biological pesticides applied against the major insect pests. These pesticides were applied to a variety of field, forage, and vegetable crops at several locations in Illinois. Resistant or tolerant crop varieties and genetically engineered corn varieties were assessed for efficacy of major insect pests of their respective crops. All trials generated meaningful data to support current integrated pest management (IPM) recommendations and the development of new IPM approaches.

Cropping impact on diamondback moth
A. Gonzalez-Rodriguez, C.Eastman
In a three-year study, intercrops of cabbage plus companion crops (tomato, sweet alyssum, safflower, sweet corn, and soybean) or trap crops (sweet alyssum, mustard) were evaluated for their effect on the diamondback moth, a major pest of crucifers, and its natural enemies. Corn reduced pest numbers on cabbage in one year but not the next. Tomato also reduced pest numbers. Sweet alyssum increased diamondback moth populations on cabbage when used as a companion planting and, along with mustard, was effective as a trap crop in reducing pest densities. Diadegma insulare was the most abundant parasitoid of diamondback moth.

Aphid preference for virus-infected plants
A. Fereres (Visiting Scientist, Spain), G. Kampmeier, M. Irwin
The progress of nonpersistently transmitted virus epidemics can be substantially altered by the degree of aphid attraction and preference for virus-infected plants. Scientists are investigating the degree of attraction/preference of winged aphids to soybean or pepper plants that have been previously infected with nonpersistently transmitted viruses, such as soybean mosaic virus or potato virus Y. Visual cues, such as color or changing patterns of infected versus uninfected leaves, may change aphid landing choices. Results of preliminary experiments using different-colored ceramic tiles indicate that the green-peach aphid prefers landing on yellow versus green or brown tiles.

Plant-based insecticides
U. Eckenbach, D. Seigler and R. Metcalf (University of Illinois), R. Lampman, R. Novak
The evolutionary interaction between plants and herbivores has led to the production of a vast array of secondary plant compounds that often exhibit considerable activity against insects, including acute toxicity and growth inhibition. Secondary plant compounds may provide novel approaches for controlling insects. This research screens plant extracts and pure botanical products for activity against mosquitoes and greenhouse pests. Several plant species have already yielded extracts with a high level of larvicidal activity (less than 50 parts per million). Ongoing studies include the identification and analysis of active compounds and bioassays with a wide range of mosquito species.

Persistence of microbial insecticides
J. Siegel, A. Smith (University of Illinois), R. Novak
Cellular fatty acid profiles have been created for microbial insecticides used in vector control and in agriculture, specifically Bacillus thuringiensis serovars aizawai, kurstaki, and israelensis, as well as a new mosquito larvicide, Bacillus sphaericus. These profiles are an essential tool for determining whether bacteria with mosquito activity that INHS researchers discover are indigenous or commercially produced. This technique was used during summer 1996 and this past summer to evaluate the persistence of commercial microbial insecticides in tires. Researchers have also identified Illinois strains of Bacillus sphaericus and Bacillus thuringiensis serovar israelensis.

Efficacy of a new microbial larvicide
J. Siegel, R. Novak
A primary concern in mosquito control has been the loss of insecticides. As current insecticides are phased out, a few products are under development to replace them. One of the few new mosquito larvicides is a microbial product, VectoLex, manufactured by Abbott Laboratories. In 1997, Survey scientists evaluated the ability of VectoLex to control Culex restuans and Culex pipiens (vectors of St. Louis encephalitis) as well as Aedes triseriatus (vector of LaCrosse encephalitis) in waste tires. VectoLex was effective and controlled mosquitoes for > 70 days. VectoLex also was effective for control of Culex restuans and Culex pipiens in catch basins.

Management of corn rootworms in Illinois
M. Gray, K. Steffey
In 1997 INHS researchers will cooperate with a private consulting firm (Midwest Consulting Services) and Purdue University entomologists in an effort to manage densities of corn rootworms in a 16-square-mile area. The primary management strategy will be to prevent corn rootworm adults from laying eggs in soybeans and eliminate the need for a soil insecticide at planting in rotated corn. By targeting insecticide applications at the egg-laying beetles, researchers predict that the overall density of corn rootworms in the 16- square-mile area can eventually be lowered to a noneconomic level.

Hybrid compensation to rootworm injury
M. Gray, K. Steffey, J. Shaw
Producers are very interested in how well corn hybrids compensate for corn rootworm larval injury. In response to this interest, a long-term investigation was conducted from 1993 to 1996 in DeKalb and Urbana that explored the manner in which corn plants compensate for larval injury. Large root systems in July and August were generally positive factors in contributing to yield; however, compensatory root regrowth, particularly when soil moisture was adequate, negatively affected yield. Root regrowth typically had a positive effect on yield following larval injury under conditions of inadequate soil moisture.

Study on rootworm economic threshold
M. O'Neal, M. Gray, K. Steffey, E. Levine, J. Spencer
In 1996, researchers began on-farm investigations with 24 producers in east-central Illinois. The goal of this research was to develop an economic threshold for western corn rootworm adults in soybean fields. The development of an economic threshold is critical for the development of pest management programs for the western corn rootworm. Growers in east-central Illinois have increased their use of soil insecticides on rotated corn from 13% (prior to 1996) to over 75%. At the completion of this research, a sampling protocol and an economic threshold will be provided to growers and crop consultants. These tools should decrease the overuse of soil insecticides.

Effect of rootworms on soybean yield
E. Levine, J. Spencer
Western corn rootworm (WCR) beetles readily feed on soybean blossoms in the field. To determine if this could have a negative impact on yield, flowering plants were covered with mesh bags and half the plants were infested with western corn rootworm beetles from east-central Illinois, where WCR densities in soybeans are unusually high. At harvest, pods from infested plants weighed on average 6.1% less than those from uninfested plants. Although not significant in this preliminary study, the results are provocative enough to warrant repeating the study with even greater replication.

Microbial control agents of the gypsy moth
J. Maddox, L. Solter, D. Onstad, M. Jeffords, M. McManus (U.S. Forest Service)
The gypsy moth is a very serious nonindigenous pest of hardwood forests in the U.S. Typical for nonindigenous pests, the gypsy moth in North America does not have many natural enemies that are important control agents in its native range. Researchers have isolated at least seven species of microsporidia from gypsy moths collected in Austria, Bulgaria, the Czech Republic, Germany, Romania, and the Slovak Republic. Ultimately, the goal is to introduce the most appropriate of these microsporidia into North American gypsy moth populations as classical biological control agents. The host specificity and biological characteristics of these microsporidia are being examined.

Biological control of purple loosestrife
R. Wiedenmann, D. Voegtlin, S. Post
Survey researchers are rearing and releasing leaf-feeding beetles to help solve problems with purple loosestrife in northern Illinois wetlands. Beetles are grown throughout winter and early spring, then adult beetles overwinter in a refrigerator. After this "overwintering," beetles are placed onto plants to produce a new generation for release directly into the wetlands. In 1996, researchers released 167,000 beetles at 34 natural-area sites throughout northern Illinois. In early 1997, scientists added on-site rearing by county and state partners to our rearing and release program.

European corn borer management
D. Onstad, E. Brewer
INHS researchers created a model for predicting induction of diapause in European corn borer populations during the summer. Diapause, which is the insect's resting state, allows the pest to overwinter. The fraction of corn borers entering diapause during the summer determines the magnitude of future generations and the level of subsequent damage to corn. We are also modeling the development of resistance to genetically engineered corn by the European corn borer. New varieties of corn contain the Bacillus thuringiensis toxin that can kill many larvae, but this strong pressure on the insect population can also lead to resistance in the pest.

Alfalfa weevil management
E. Armbrust, S. Roberts
A three-year study, initiated in 1995 to determine the best alfalfa weevil management practices, continues. The site was a heifer farm in Clinton County near Centralia. The management practices include a spring spray for alfalfa weevil control, fall grazing of alfalfa, early spring alfalfa harvest, spring grazing of alfalfa, late winter/early spring burning of alfalfa, early spring pyrethroid treatment, fall harvest of alfalfa after the first killing frost, and an untreated check. Alfalfa weevil life stages, predators, parasites, and pathogens are being studied. This study should help optimize alfalfa weevil control and integrate alternative control practices.

Systematics of the Chamaemyiidae
S. Gaimari, M. Irwin
Chamaemyiid larvae (Diptera: Chamaemyiidae) are predators on a wide range of soft-bodied homopterans including aphids, scales, and mealybugs. Despite their potential importance as predators of these insects, chamaemyiid larvae are poorly known taxonomically. Survey researchers are studying several aspects of this predaceous family, including nomenclatural status, revisions of several poorly understood and understudied genera, biological studies, and descriptions of several new genera and species. Survey researchers are also considering the systematic relationships within the family, using adult and immature morphological characters, life history information, and molecular techniques.

Revision of the genus Thereva
K. Holston, M. Irwin
As part of the worldwide revision of Therevidae, the type genus Thereva Latreille is currently being revised. Thereva is a widespread genus, including species from the Nearctic, Palaearctic, Afrotropical, and Neotropical regions. A systematic database of species names associated with Thereva has been initiated, and morphological studies to both define the groups within Thereva and examine the monophyly of Thereva are under way. Subsequent phylogenetic analyses of Thereva will be conducted using morphological, molecular, and natural history information. A short-term behavioral study of low-altitude, dune-associated Californian species of Thereva and other therevids in the same community is planned for 1997.

Revision of the genus Ozodiceromyia
S. Gaimari, M. Irwin
The genus Ozodiceromyia (Diptera: Therevidae) contains 115 Nearctic and northern Neotropical species, of which 80 are new to science. As larvae, these flies are subterranean predators of larval insects, such as beetle grubs. These important predators may be useful in assessing health of dry, friable soil habitats. Despite its abundance in agricultural habitats, Ozodiceromyia is poorly understood taxonomically. Survey researchers are seeking a better understanding of the genus and relationships with other therevid genera as well as relationships within the genus. A full phylogenetic and biogeographic revision is near completion, using traditional adult taxonomy, life history information, and molecular systematic techniques.

Revision of the genus Brachylinga
M. Metz, M. Irwin
Work continues on the revision of the New World genus Brachylinga (Diptera: Therevidae), which are predators of immature insects in loose, sandy soils. Specimens from major North American collections have been borrowed and placed in 40 sort groups. Researchers expect to resolve approximately 60 species, although only 16 names currently exist. Despite their impact on soil-inhabiting larvae, little is known about the ecological impact of Brachylinga, but collections from the southwestern U.S., southern Texas, and Guatemala have added significantly to our understanding of the group, as will future collections from the southwestern U.S. and Chile.

Revision of the Genus Lindneria
M. Metz, M. Irwin
The Neotropical fly genus Lindneria (Diptera: Therevidae) is known from only a few specimens and is rarely collected. A specimen in Dominican amber has prompted a revision of this small, poorly known genus. The one extant holotype is currently in hand, while 12 species have been resolved from specimens from major collections. The information gained from the phylogenetic relation of the amber specimen to extant species should have some impact on the relations of other genera in the family.

Collection of viable microsporidian spores
J. Maddox, L. Solter
In 1966 Survey scientists began preserving living spores of microsporidia in liquid nitrogen. Spores placed in liquid nitrogen in 1966 are still infectious to their hosts, but spores stored in 50% glycerol/water are more infectious than spores stored in water. The INHS collection of viable spores has grown tremendously since 1966 and now contains more than 1,000 samples of microsporidian spores representing many species, both described and undescribed. The collection is a source of many potentially important biological control agents, and it is important because it allows us to examine previously described microsporidia using modern molecular and biochemical techniques.

Spore-forming bacteria in amber
J. Siegel, A. Smith (University of Illinois), R. Novak
The movie Jurassic Park captured the public imagination with its vision of the resurrection of dinosaurs from DNA preserved in amber. One year after the release of the movie, California researchers claimed to have revived 20-million-year-old bacteria in amber. Survey scientists and University of Illinois researchers are interested in replicating that work, with an emphasis on identifying mosquito pathogens. To date, three cultures have been recovered. One of the cultures, Bacillus sphaericus, is indeed a mosquito pathogen; the second species recovered, Bacillus licheniformis, is not. We have not yet identified the third isolate.

Body and genitalia size in Ozodiceromyia
M. Metz, M. Irwin
Dipterists depend heavily on genitalic characters for species designations. This study investigated the morphological variation of genitalic characters in relation to body size using morphometric analysis and comments on the application of these characters in taxonomy and systematics. A genitalic character that did not covary with body size was found in females, while all male genitalic characters measured covaried with body size. The differential variation found in the genitalia of males and females suggests a limit for quantitative characters in species designations as well as a possible sexual selective character in females.

Systematics of the Phylum Microsporida
J. Maddox, L. Solter
The Phylum Microsporida, formerly a Class within the Phylum Protozoa, is a group of unicellular obligate pathogens. Most animal phyla are infected by microsporidia, but microsporidia are primarily pathogens of arthropods and are often very important natural control agents of insects. Only a small number of existing microsporidian species have been described, the phylogenetic relationships between genera are poorly known, and the phylogenetic significance of traditional morphological and ultrastructural characters is undetermined. We regularly describe new species of microsporidia and use both molecular and morphological information to evaluate the taxonomic importance of traditional morphological and ultrastructural characters.

Rootworm beetle movement into soybeans
E. Levine, J. Spencer
Western corn rootworm (WCR) injury to corn planted after soybeans in east-central Illinois has been increasing in severity for several years. Lab and field studies confirm that root injury was a consequence of WCR egg-laying in soybean fields during the previous summer. Movement of WCR beetles into soybean fields in the "problem area" was monitored with transects of vial traps extending from corn into adjacent soybeans. Beetles were captured in soybeans just one week after first capture in corn. The number captured in soybean fields greatly surpassed that captured in cornfields for most of the summer.

Wind tunnel analysis of rootworm flights
J. Spencer, S. Isard, E. Levine
Responsiveness to soybean foliar cues is hypothesized to account for movement of western corn rootworm beetles from corn into soybeans. In this study, beetles were allowed to fly freely and land within an array of corn and soybean plants maintained in a large wind tunnel. Initially, corn seemed more attractive than soybeans as landing targets; however, elevation of soybean plants by one meter made them as attractive as corn. Beetles from locations in and outside the region where egg-laying in soybeans leads to problems in first-year corn exhibited no significant preference to associate with corn or soybean plants.

Feeding behavior and rootworm color
J. Spencer, E. Levine
While observing western corn rootworms in regions where egg-laying in soybeans is a problem, researchers noted beetles moving between adjacent corn and soybean fields and that beetles collected in soybeans were significantly greener in color than those from cornfields. The percentage of green individuals was greatest (89%) where soybeans grew far from cornfields and least (26%) in continuous cornfields. In adjacent fields, percent green insects was similar across the corn-soybean interface (42%). Gut content analysis corroborated a diet-color relationship and revealed that 14% of insects had recently fed on both crops. Color may indicate past behavior.

Earthworms in Illinois agroecosystems
E. Zaborski, S. Roberts
Earthworms have profound effects on the ecosystem maintenance functions performed by soils, such as nutrient recycling and retention, water infiltration, and carbon storage. Soil management practices affect the abundance and species composition of earthworm communities. To better understand how earthworms respond to soil management practices, INHS researchers are sampling populations in farm fields around the state that differ in tillage and crop rotation. Also, by relating our measurements of earthworm populations to measurements of soil physical/chemical characteristics and soil processes, researchers are evaluating the potential of using earthworms as an indicator of soil quality.

Soy oil derivatives as mosquito larvicides
R. Lampman, U. Eckenbach and D. Seigler (University of Illinois), R. Novak
In the past 30 years, the arsenal of insecticides for controlling public health pests in Illinois has declined. Unfortunately, we are not immune from outbreaks of mosquito-borne diseases or the invasion of new species in Illinois, such as the Asian tiger mosquito. The goal of this research is to develop environmentally safe alternatives for mosquito control. Laboratory tests demonstrated that formulations of methylated soy oil with a small amount of surfactant are effective agents against mosquito larvae. The suitability of these soy oil products in wetland areas, catchbasins, and tires is being examined.

Soybean feeding by rootworm beetles
J. Spencer, E. Levine
The western corn rootworm beetle, whose egg-laying in soybeans threatens crop rotation, has inexplicably begun to feed on soybean foliage. Initial experiments conducted to assess consequences of a soybean diet indicated soybean-fed beetles were less vigorous than those fed corn diets, but that vigor could be rescued if soybean-fed individuals were given corn. Beetles fed only soybean foliage failed to mature eggs, weighed significantly less, and died weeks earlier than others given corn foliage or artificial diet. Beetle movement back into corn after feeding and egg-laying in soybeans may be necessary to compensate for a poor diet.

Nematode parasite of earthworms
E. Zaborski
Earthworms are thought to be free of important nematode parasites. During the winter of 1996-1997, Survey researchers discovered a nightcrawler, Lumbricus terrestris, that was parasitized by a nematode. Within days, the earthworm died and released several tens of thousands of nematodes. These nematodes were able to infect and kill healthy nightcrawlers. This may be the first reported instance of an parasitic nematode attacking earthworms. Further studies are being conducted in the laboratory to identify this nematode, describe its biology, and understand its importance as a mortality factor for earthworms.

Effects of global change on mosquitoes
R. Novak, N. Krasavin, E. Kennedy
Global warming and an increase in biologically destructive ultraviolet (UV) radiation are two predicted consequences of the accumulation of greenhouse gases and depletion of the stratospheric ozone layer by photoreactive compounds. A growing concern is that these factors will indirectly threaten the health and welfare of humans and other animals due to an increase in the distribution and abundance of insects and their associated pathogens. Researchers will determine how increased temperature and UV-B radiation affect the survivorship, developmental rate, biochemistry, and fitness of three mosquito species, including vectors of malaria, dengue virus, and St. Louis encephalitis virus.

Surrogate assay for ovipositing rootworms
M. Vodkin, K. Ramsdell, E. Levine, R. Novak
Within the last three years increasing numbers of farmers in east-central Illinois who annually rotate corn have been experiencing problems with injury from the western corn rootworms (WCR). Circumstantial evidence suggests that the WCR has overcome rotational strategy by ovipositing in soybeans fields. In order to monitor the scope of the problem prior to planting and identify fields or areas at risk, a surrogate assay has been developed. An oligonucleotide has been identified that distinguishes WCR found only in problem areas. Further tests are ongoing to determine whether this particular assay will be predictive.

Host specificity of insect pathogens
L. Solter, J. Maddox
The most important concern relative to the safety of pathogens used as biological control agents of insects is host specificity. This is especially true for nonindigenous insect pathogens intended for introduction into the U.S. as classical biological control agents. Host specificity experiments must be conducted in the laboratory before a nonindigenous pathogen is released into the environment. It is, therefore, essential that laboratory estimates of host specificity reflect the host specificity in the field. Survey scientists are examining the basic factors that influence host specificity and comparing laboratory results (physiological host specificity) with host specificity under field conditions (ecological host specificity).

Algorithm for sequence databases
M. Vodkin, R. Novak
Public and commercial programs are available to search for sequences in the nucleic acid or protein databases that are homologous to a query. However, the popular programs are ill-suited to manipulate discontinuous data that are frequently encountered with RAPD analysis (oligonucleotides) or N-terminal analysis of a partial proteolytic digestion (oligopeptides). A strategy was designed using an extant program, FindPatterns in the University of Wisconsin GCG package, to manipulate such data. The program was successful in identifying a previously unidentified protein from a dataset. Its utility has also been confirmed for the nucleic acid databases.

Spatial dynamics of leafhopper in alfalfa
S. Roberts, E. Armbrust
Interhabitat movement of the potato leafhopper was monitored in St. Clair County at the Southern Illinois University Belleville Research Center. This study monitors the movement of potato leafhoppers in habitats other than alfalfa. Sticky traps were used in six sites. Traps were placed on wooden stakes five feet from ground level. Traps were operated from May through October. Peak counts occurred during June 18-26. This study may help to predict when and from what habitats damaging populations of potato leafhoppers may occur.

Death march behavior in caterpillars
D. Guyot, W. Ruesink
Many caterpillars, when infected with baculoviruses, show increased locomotor activity, often climbing to the top of a plant just before dying. INHS research into the mechanism underlying this behavior is currently focusing on blood-borne factors associated with infection. A better understanding of how pathogens affect host behavior may lead to improving the efficacy of microbial pesticides.

Habitat selection by braconid stemborers
R. Wiedenmann, C. Rutledge
Researchers are determining how to use novel-association parasitic insects safely and effectively for biological control of stemborer pests. Using an olfactometer in the laboratory, researchers assessed responses of three congeneric parasites to volatile plant chemicals from various grasses (corn, big blue stem, sorghum) and nongrasses (tomato, cabbage). Each species prefers--and avoids--cues from different plant species. Next, stemborers were allowed to feed on plants to determine if damaged plants differ in attractiveness. The results show that these parasites select only certain habitats, meaning there is less potential for them to find, attack, and harm nontarget species.

Electronic light trapping of leafhoppers
S. Roberts, E. Armbrust
Potato leafhopper movement was monitored by using a modified electronic light trap. An incandescent yellow light bulb for bugs was used in place of the UV light. The trap was set to operate one hour before and after sunset and sunrise. Light trap catches were compared to those of sticky traps from May 31 to September 24. Leafhoppers were detected earlier in the light trap than on sticky traps. Peak numbers in the light trap occurred on July 6 (total of 507) while peak counts on the sticky traps did not occur until July 19-25 with a mean of 85/trap.

Potential gypsy moth defoliation in Chicago
D. Onstad, M. Jeffords
A model for defoliation, refoliation, and tree mortality in Chicago was developed based on the number of trees and leaf biomass for each tree species, classified according to its attractiveness to gypsy moth. The highest percentages of preferred tree species and defoliation are predicted to occur on vacant lands, golf courses and parks, and residential areas, respectively. Overall, the defoliation potential is modest--from 14% in Chicago and suburban Cook County to 26% in DuPage County--but localized defoliation can be higher. Less than 0.1% of Chicago-area trees are predicted to die because of gypsy moth defoliation.

Interactions between parasites and hosts
R. Wiedenmann, M. Alleyne
An important aspect of using novel parasites for biological control is the array of physiological host-parasite interactions. INHS scientists found that physiological compatibility of three related braconid parasites differs among parasite species, depending on which stemborer species is attacked. Cotesia flavipes is encapsulated frequently by the stemborers Diatraea grandiosella and D. saccharalis, whereas Cotesia chilonis is never encapsulated. In contrast, the European corn borer is totally unsuitable for any of these three parasites. Biochemical and immunological mechanisms are being explored to explain the patterns of compatibility. Results also indicate the narrow specificity--and therefore, safe use--of these novel stemborer parasites.

Insect pathogen databases on the Web
D. Onstad, D. Dockter (University of Illinois), E. Brewer
The Ecological Database of the World's Insect Pathogens (EDWIP) and the Viral Diseases of Insects in the Literature (VIDIL) database were placed on a new INHS Web server located at http://insectweb.inhs.uiuc.edu/ so that scientists and government regulators could access them. VIDIL contains over 3,000 references up to 1980. EDWIP contains over 5,000 records of associations between nonvirus pathogen species and insect species. The virus database has over 1,500 records. The complete database has records for 3,500 insect species. The nonvirus pathogens include over 50 species of bacteria, over 300 species of fungi, and 1,200 protozoa.

Fingerprinting virus strains
M. Vodkin, G. McLaughlin, R. Novak
Strain variation has been associated in some cases with altered virulence in a variety of microorganisms. In a model system of the amoeba, Acanthamoeba spp., closely related species have been isolated that are pathogenic or nonpathogenic to humans. A polymerase chain reaction assay was established to distinguish between the two phenotypes. A similar philosophy is envisioned for arboviral systems to test the hypothesis of whether there are genetic markers that correlate among viruses that are enzootic, epizootic, or epidemic.

Statewide monitoring of rootworm beetles
E. Levine, J. Spencer
Collecting trips across the mid-section of Illinois were made in mid-August 1996 to sample population densities of western corn rootworm (WCR) beetles in soybean fields. Trips originated in east-central Illinois, where severe injury to first-year corn following soybeans has been reported, and terminated in west-central Illinois, where there are no reported WCR problems. Locations in east-central Illinois had the highest WCR densities in soybeans while west-central Illinois locations had the lowest densities. In central Illinois, intermediate densities were found, reminiscent of population levels in east-central Illinois before first-year corn problems were recognized.

Soybean Insect Research Information Center
M. Irwin, L. Hanson, E. Brewer
The Soybean Insect Research Information Center (SIRIC) is a reference center for the study of arthropods associated with soybeans and is intended to serve as a first line of defense against outbreaks of new soybean pests. The center produces an electronic database that contains the world's scientific and research literature on soybean-related arthropods, and collects and stores printed copies of 99% of the papers found in the database. First established in 1969, SIRIC was closed in 1990 and re-opened with a new librarian in January 1997. The database is now being converted to a current computer platform and updated with information from 1990 to 1997.

Cellular fatty acid identification of E. coli
J. Siegel, A. Smith (University of Illinois), R. Novak
The medical entomology laboratory is interested in emerging diseases. Although the primary interest is in vector-borne disease, researchers are interested in applying laboratory techniques developed to address health concerns of Illinois citizens. Escherichia coli O157:H7 is an emerging foodborne pathogen that can be fatal; toxins from this bacterium have caused the death of children. In collaboration with the Department of Veterinary Pathobiology, researchers are using fatty acid fingerprinting techniques to identify bacterial strains that are currently circulating in the U.S. These profiles will enable researchers to identify cases caused by Escherichia coli O157:H7 in Illinois and trace the source.

Exotic pest detection surveys
C. Helm, E. Brewer
In spite of the best efforts of federal Plant Protection and Quarantine officials, foreign plant pests continue to be introduced and established within the borders of the U.S. and Illinois. Through the U.S. Department of Agriculture's Cooperative Agricultural Pest Survey program, Survey scientists are actively involved in detection and monitoring programs and database management designed to meet the unique challenges presented by these accidentally introduced pests. Trapping efforts are currently directed at documenting the distribution and status of the pine shoot beetle within commercial Christmas tree plantations and established stands of pines.

Threshold level of detection of virus
M. Vodkin, K. Ramsdell, C. Mitchell, R. Novak
A viral stock of western equine encaphalitis virus (WEEV) was prepared and assayed by tissue culture. Dilutions were made from the stock and provided as coded samples to two independent laboratories, INHS and the Centers for Disease Control, to assay by polymerase chain reaction. Both laboratories were able to detect the same levels of virus, about 4.7 log -10 infectious units/ml.

Organic matter and nitrogen cycling
E. Zaborski
In soils, organic matter dynamics and biological processes govern nitrogen availability and retention. In agricultural soils, short- and long-term nitrogen cycling might be optimized through management of soil organic matter. Younger soil organic matter fractions respond most rapidly to changes in management, and are most active in nutrient transformations and biological activity. Researchers are studying younger organic matter fractions under different management systems, and relating them to soil biological activity and nitrogen cycling. The long-range goal is to optimize the nitrogen supplying capacity of managed soils and reduce the impact of nitrogen losses on off-site resources.