1) Project Title: Assessment of soybean aphid parasitoids, predatory flies, and pathogens in cultivated habitats in soybean production areas

Investigators: Michael J. Brewer and Takuji Noma, IPM Program, Michigan State University

Contact: Michael J. Brewer (brewerm@msu.edu)

Project Description: Since its invasion, the soybean aphid, Aphis glycines, has been a major economic threat for soybean production in Michigan and surrounding regions. We have been monitoring preexisting parasitoids, predatory flies and pathogens in lower Michigan that are adapting to utilize this new invasive species. We are currently assessing diversity, seasonal occurrence, and abundance of these enemies in soybean and surrounding habitats (alfalfa, corn, and wheat-clover) to understand aphid-enemy-habitat interactions. Two methods were used to sample aphid enemies from June through September. First, we exposed potted soybean plants infested with A. glycines to detect parasitoids and predatory flies attacking A. glycines in soybean and surrounding habitats. Second, we inspected individual plants of alfalfa, corn, soybean, wheat, and clover for aphids and aphid enemies. Early assessment indicated that each crop was associated with a distinctive aphid fauna and parasitoid community, although some parasitoids detected in non-soybean crops were relevant in A. glycines control. The seasonal populations of A. glycines were low in 2004, never reaching the economic threshold. Five parasitoid species, which were also found in 2003, were detected preying upon A. glycines in 2004. The most common A. glycines parasitoid was Lysiphlebus testaceipes, which became abundant when A. glycines populations peaked in August. The exotic parasitoid, Aphelinus albipodus was rarely detected from A. glycines but readily detected from Rhopalosiphum padi on corn. The related preexisting species, Aphelinus asychis, was recovered more frequently from A. glycines. Predatory flies as a whole were more abundant attacking A. glycines than parasitoids. The cecidomyiid, Aphidoletes aphidimyza, was particularly abundant. Predatory flies were less habitat and host specific compared with parasitoids, although selected syrphid species appeared to have considerable aphid host preference. Fungal pathogens were most commonly detected infecting pea aphids in alfalfa and clover, but disease was rarely observed in sparse populations of A. glycines.

2) Project Title: Intraguild predation of soybean aphid.

Investigators: Alejandro C. Costamagna and Douglas A. Landis, Michigan State University

Contact: Doug Landis (landis@msu.edu)

Project Description: Our goal was to evaluate the joint impact of predators and parasitoids on A. glycines populations and to examine the role of predators in limiting parasitoid impacts via intraguild predation (IGP).

During 2004 we conducted two experiments. In the first field experiment we combined controlled releases of the native soybean aphid parasitoid, Lysiphlebus testaceipes (Hymenoptera: Braconidae) with exclusion of predators in 1 m3 cages at East Lansing, Michigan. Treatments included: 1) total exclusion cages without aphids or natural enemies (plant damage control), 2) total exclusion with aphids (aphid population growth control), 3) partial exclusion with aphids and parasitoids (parasitoid treatment), 4) sham cage with aphids (predator treatment), 5) sham cage with aphids and parasitoids (predator + parasitoid treatment), and 6) no-cage area with aphids alone (open control treatment). Treatments 2 to 5 used cages with window of 2 mm mesh that allowed free movement of parasitoids and aphids in and out of the cage. Cages in treatment 1 were made using < 1 mm mesh that prevented parasitoid and aphid movement. All the treatments initially received the same level of aphids (100 aphids/m2) on June 21, 2004. Following the July 5th sample, windows were adjusted to allow a larger area for predators to enter. Our preliminary results show that open cages and treatments open to predators contained significantly reduced soybean aphid numbers but that parasitoids alone were not effective in controlling aphid populations (Fig. 1). The presence of predators also increased soybean biomass (August) in comparison with plants with aphids and no predators. Yield data is not yet available.

We conducted a similar experiment using natural parasitoid populations in the KBS-LTER site, Hickory Corners, Michigan. Using tomato cage frames we differentially excluded all natural enemies (< 1 mm mesh, Aphid treatment) or only large predators (2 mm mesh, Mesh treatment), thus allowing natural parasitism to occur. We also included un-caged plants with and without aphid manipulation (Open and Field treatments), plants enclosed with a sham cage (Sham treatment) as a cage control, and plants caged without aphids (Plant treatment). Our preliminary results again showed strong impacts from predators (mainly Coccinellidae) but no control achieved by extant parasitoid populations (Fig. 2). Although we observed direct evidence of intraguild predation (mummies being consumed), IGP alone does not explain the failure of parasitoids to control soybean aphid in these two experiments.

Figure 1. Results of the experiment of a multiple enemy assemblage on A. glycines control, East Lansing, Michigan 2004. Legend: paras = + parasitoid treatment, pred = + predator treatment, PP= predator + parasitoid treatment.

Figure 2. Results of the experiment of a multiple enemy assemblage on A. glycines control, without parasitoid manipulation, at the KBS-LTER Biodiversity plots.

3) Project Title: A Comparison of Native Michigan and Nonnative Plants to Provide Resources to Natural Enemies

Investigators: Anna K. Fiedler, Douglas A. Landis, Department of Entomology, 204 Center for Integrated Plant Systems, Michigan State University, East Lansing, Michigan 48824-1311

Contact: Doug Landis (landis@msu.edu)

Project Description: The use of plants to provide nectar and pollen resources to natural enemies via habitat management is a growing focus of conservation biological control. While most guidelines recommend plants not native to the area of study, there is no reason to suspect that plants native to an area cannot perform as well as non-natives. Use of native plants for habitat management has several benefits. Many of the natural enemy species affected by conservation biological control are native insect species, which may be better adapted to feed on native plants. In addition, native plants are pre-adapted to the environment and its natural enemies. Use of them enhances native biodiversity and may aid in restoring native communities.

We compared of a set of forty-six native Michigan and five non-native plants for their effectiveness as resource plants for natural enemies. Insect abundance and diversity were measured at flowering plants in peak bloom during the 2004 growing season. A set of plant and flower characteristics: plant height, minimum and maximum flower height, flower color, flower apparency (floral display) and nectar accessibility, were measured to determine which are best correlated with natural enemy visitation. Preliminary results indicate that the number of insects found at flowers is strongly related to plant nectar accessibility and floral apparency, indicating that insects are actually visiting the plant to access floral resources. In addition, plants with a large number of total insects frequently have a larger number of natural enemies visiting them. This process of comparing plant characteristics and insect visitation allows rapid plant screening to maximize resource plant effectiveness before larger-scale plantings in the field or in on-farm trials.

4) Project Title: Control of Asparagus Miner, (Ophiomya simplex) in Michigan asparagus.

Investigators: Beth A. Bishop, Edward J. Grafius and Walter L. Pett. Department of Entomology, Michigan State University

Contact: Edward J. Grafius (grafius@msu.edu)

Project Description: The Asparagus miner (Ophiomya simplex) is a small fly that lays eggs under the epidermis at or near soil level of asparagus during the fern stage. Larvae mine the cortex and pupate within. Asparagus miner may harbor Fusarium and passively vector it. Pupae may be an overwintering source of Fusarium. Young fields may be especially vulnerable, since early in the season they (and volunteer asparagus plants) are the only source of fern, which adult flies require for oviposition.

For the past several years we have studied the biology and control of asparagus miner in Michigan asparagus fields. In late 2003 we found several parasitized asparagus miner pupae in asparagus plants from Oceana County, These were solitary parasitoids and were identified as follows: Hymentoptera: Eulophidae: Neochrysocharis sp. (Miichael Gates, Systematic Entomology Laboratory, Agriculture Research Service, US Department of Agriculture). In 2004 we found several asparagus miner pupae that were parasitized with a multiple parasitoid (Hymenoptera: Braconidae, possibly Ophius sp). At present there are no reports of asparagus miner parasitoids in the US literature.

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5) Project Title: The effect of a reduced-risk insect management program on natural enemies of the grape berry moth Endopiza viteana Clemens (Lepidoptera: Tortricidae).

Investigators: Paul E. Jenkins and Rufus Isaacs, Department of Entomology, Michigan State University.

Contact: Rufus Isaacs (isaacsr@msu.edu)

Project Description: The grape berry moth (GBM), Endopiza viteana Clemens, is a primary pest of grapes in the eastern U.S. Recent registration of the insect growth regulator methoxyfenozide for use in grapes provides an opportunity for selective control of this key insect pest without disruption of biocontrol agents. The current project compares levels of GBM parasitism and predator abundance in vineyards managed using methoxyfenozide for berry moth control to vineyards managed using conventional broad-spectrum insecticides. Two similarly sized vineyards (3.5-10 acres) at each of five commercial ‘Concord’ grape (Vitis labrusca) farms in southwest Michigan were selected for this study. Flight of male GBM was monitored in each treatment all season using pheromone traps to assess pest phenology. Unbaited yellow sticky traps were deployed in each vineyard all season to monitor generalist natural enemies at each vineyard interior, border, and adjacent habitat border. Methoxyfenozide applications were based on weekly scouting and comparisons between programs were targeted at second and third GBM generations, when GBM pressure is highest. GBM infested berries were collected from both treatments to measure GBM larval parasitism. In the first year of this study (2003), the parasitism rate of GBM was found to be greater in GBM infested berries collected from the methoxyfenozide program than in the conventional program. No significant difference in the abundance or community of natural enemies from yellow sticky trap collections was detected between treatments. Data from the second year of this study (2004) are still being analyzed.

6) Project Title: The effect of agroecosystem modification on biological control agents of the grape berry moth Endopiza viteana Clemens (Lepidoptera: Tortricidae).

Investigators: Paul E. Jenkins and Rufus Isaacs, Department of Entomology, Michigan State University.

Contact: Rufus Isaacs (isaacsr@msu.edu)

Project Description: The grape berry moth (GBM), Endopiza viteana Clemens, is a primary pest in eastern U.S. juice grape production. The ancestral host of this pest is wild grape (Vitis spp.). Recent research at MSU and grower experience suggests that removal of wild grape hosts in woodlots adjacent to vineyards can reduce GBM pressure. We are measuring the long-term effect of this cultural control practice on the GBM parasitoid community and generalist natural enemy abundance within cultivated vineyards. One to ten acre paired-vineyards at five farms in southwest Michigan were used for this study. Wild grape in the woods adjacent to one of the vineyards was cut (to prevent vine fruiting), thereby removing a possible refuge for both GBM and their specialist parasitoids. Adult flight of male GBM was monitored in each treatment all season using pheromone traps to assess GBM phenology. Unbaited yellow sticky traps were deployed in each treatment season-long to monitor generalist natural enemies at each vineyard interior and border, and at each adjacent wood border and interior. Infested berries were collected from both treatments to measure GBM larval parasitism. As expected, in the first year of this study (2003) no significant difference was found in the number of parasitoids emerging from GBM infested berries collected in vineyards next to woods with or without wild grape. Additionally, there was not a significant treatment difference in the abundance or community of natural enemies from yellow sticky trap collections. Data from the second year of this multi-year study are currently being analyzed.

7) Project Title: Response of Natural Enemies to Reduced Broad Spectrum Insecticide Use in Michigan Blueberry

Investigators: K.S. Mason, M.E. O’Neal, C. Garcia-Salazar, J.C. Wise, and R. Isaacs. Department of Entomology, Michigan State University

Contact: Rufus Isaacs (isaacsr@msu.edu)

Project Description: As part of a 4-year, USDA-RAMP funded project comparing pest management programs that employ either broad spectrum or reduced-risk (RR) insecticides, we measured abundance of natural enemies in the Michigan highbush blueberry agroecosystem. Two fields were chosen at each of six blueberry farms in southwest Michigan, one field received a grower standard broad spectrum pest management program (GSTD) while the second received reduced-risk insecticides. All insecticide applications were made in response to weekly scouting. Yellow sticky traps, pitfall traps, tuna-baited test tubes, fruit and foliage collections and periodic natural enemy scouting were used in each field to test whether reduction in the use of broad-spectrum insecticides can increase abundance of generalist arboreal predators (coccinellid, syrphid and lacewing), terrestrial arthropod predators (carabid and formicid), or parasitoids in RR fields. Results from this second year of the study, suggest the rate of parasitism of blueberry aphid is higher in RR fields compared to GSTD fields. Although data for this season is still being collected and analyzed, we observed greater ground foraging ant activity (number of bait stations per field with ants) in RR as compared to GSTD fields. Coccinellid, syrphid and lacewing data are not yet analyzed, but early season data indicates little or no difference in abundance of these generalist predators among management programs. Collections of infested fruit to quantify parasitism of cranberry and cherry fruitworm were made, but no parasitoids emerged from these samples. From this research, we hope to better understand the potential contribution of natural enemy populations to the control of major insect pests in blueberry.

8) Project Title: Soybean Aphid in the North Central US: Implementing IPM at the Landscape Scale

Investigators: Douglas A. Landis, Christina D. Difonzo, Michael J. Brewer, Scott M. Swinton, Mary M. Gardiner, David Ragsdale, Robert Venette, George Heimpel, Kent Olson, Matthew O’Neal, Claudio Gratton, Craig Grau, and Tom German.

Contact: Douglas A. Landis (landisd@msu.edu)

Project Description: The soybean aphid is a major new invasive pest of soybean in North America. In 2003, over 42 million acres of soybean in the North Central US were infested and over 7 million acres were treated with insecticides to control soybean aphid. Producers, industry and university research/Extension personnel have identified the soybean aphid as one of the greatest threats to the US soybean industry. Understanding and predicting the biology of soybean aphid at landscape scales is critical to effective management of multiple crops within agroecosystems.

The overall goal of this USDA RAMP funded project is to help transition the North Central US soybean industry to a sustainable and ecologically-based IPM system for soybean aphid that is compatible with the multi-pest and multi-crop ecosystems that occur in the region. Our multidisciplinary team represents expertise in entomology, plant pathology, invasive species, vector biology and agricultural economics. Our specific objectives are to: 1) conduct regional research/demonstration trials comparing IPM practices for soybean aphid, 2) understand soybean aphid biology at the landscape scale, 3) integrate soybean aphid IPM into multi-pest, multi-crop systems, and 4) develop and implement systems for delivery and measurement of soybean aphid IPM implementation and adoption.

In its native range the soybean aphid is attacked by more than 30 species of predators, 8 species of aphidiine and aphelinid parasitoids, and several fungal pathogens. Screening potential natural enemies for classical biological control of the soybean aphid is a priority. Also, biological control of the soybean aphid by the existing community of natural enemies present in the North-Central US will continue to be evaluated. Specifically, how the structure and complexity of the agricultural landscape affects the population dynamics and species richness of these natural enemies and influences herbivore-natural enemy interactions will be investigated.

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9) Project Title: Impact of Galerucella calmariensis L. on Purple Loosestrife (Lythrum salicaria L.) in Michigan

Investigators: Doug Landis, Donald C. Sebolt, Michael Haas, Michael Klepinger

Contact: Doug Landis (landisd@msu.edu)

Project Description: Purple loosestrife, Lythrum salicaria L. (Lythraceae) is an invasive wetland perennial plant that is widely established in North America and is considered a threat to native wetland flora and fauna. Two European beetles, Galerucella calmariensis L. and G. pusilla Duft. (Coleoptera: Chrysomelidae) have been introduced and distributed throughout North America for biological control of L. salicaria. Experimental releases of Galerucella spp. beetles were first made by the Michigan Department of Natural Resources in three Michigan coastal locations in 1994. In 1997 we initiated a project to rear, redistribute and evaluate the impacts of Galerucella spp. beetles. From 1997-1999 we released these beetles at additional sites throughout Michigan. Galerucella calmariensis became established at 100% of the 24 release locations monitored in these studies and persists at all sites while G. pusilla apparently failed to establish. Large populations of G. calmariensis developed from each of the 1994 releases resulting in 100% defoliation of L. salicaria. Of the 14 additional sites monitored for four to six years post-release (thru 2004), 57% (4/7) of the 1997 releases have developed large G. calmariensis populations resulting in severe damage to L. salicaria. One hundred percent (4/4) of the 1998 releases have generated developed large Galerucella populations and show moderate impacts. Sixty-six percent of sampled 1999 releases (2/3) have moderate to high Galerucella populations and show moderate impacts. While most sites show an increase in plant species richness as a result of effective biological control, other sites are showing signs of L. salicaria recovery as beetles disperse away from the defoliated release area. We expect this to be a short-term recovery by L. salicaria as beetles recolonize the release site in future years. However, this indicates the critical need for additional research on the role of Galerucella spp. in the restoration of desirable plant communities in areas formerly dominated by L. salicaria.

10) Project Title: Evaluating the Potential for Biological Control of Garlic Mustard in Michigan

Investigators: Douglas A. Landis¹, Douglas W. Schemske², Adam S. Davis³) Jeffrey A. Evans¹

¹Department of Entomology, Michigan State University, East Lansing, MI 48824
²Department of Plant Biology, Michigan State University, East Lansing, MI 48824
³USDA ARS N-319 Turner Hall, 1102 S. Goodwin Ave., Urbana, IL 61801

Contact: Doug Landis (landisd@msu.edu)

Project Description: Garlic Mustard, Alliaria petiolata (Brassicaceae) (M. Bieb) Cavara and Grande, is an obligate biennial forb that is native to Europe, the Mediterranean region, and parts of Western Asia. It is highly invasive in North America and is now present and spreading in at least 34 U.S. States and 4 Canadian provinces. Alliaria petiolata is shade adapted and a highly aggressive competitor in forest understories, edge habitats, and disturbed areas. Established populations of A. petiolata set high numbers of seeds, and seeds can remain viable in the seed bank for up to five years. Conventional control methods have proven ineffective on all but the smallest infestations. Potential biological control organisms are currently under testing in Europe and in quarantine in the United States for host specificity and effectiveness.

We began taking baseline species composition data at eight A. petiolata infested sites representing a variety of forest types in the Lower Peninsula of Michigan and will document the effects of changes in garlic mustard abundance on the existing community. Two parallel transects of ten 1m x 1m plots spaced 10m apart were established in April 2003 at each site and percent garlic mustard coverage, species percent composition, percent coverage of plant, rock, and soil were recorded. All measurements have been repeated annually during fall and spring of 2003 and 2004 and will be taken again in 2005.

A study was initiated in 2003 at one site on the MSU campus and at Ft. Custer Military Training Center, near Battle Creek, MI, to estimate the effect of herbivore damage on A. petiolata populations. 25 randomized plots each containing 32 A. petiolata plants/m2 were divided into five treatment groups with five replicates each and were thinned using glyphosate (1.5%) during the spring. Plant densities in the five treatment groups were 0, 8, 16, 24, and 32 A. petiolata plants/ m2. Control plots (with 32 plants/m2) were treated with distilled water. Treatments were repeated in 2004 and will be repeated again in 2005. Thinning is meant to mimic the effect of severe herbivore damage on populations of A. petiolata. This will allow us to estimate the percent damage required by biocontrol agents to effectively control this invasive weed.

A study of variability in Alliaria petiolata demography was initiated in June 2004. The first objective of this effort is to characterize spatial variability in A. petiolata demography. The second objective is to model the effects of potential biocontrol agents on A. petiolata populations across Michigan and determine whether single or multiple agent biocontrol will be necessary. Demographic parameters are being measured for A. petiolata populations at eight locations in southern Michigan representing a latitudinal and longitudinal gradient as well as both high and low levels of A. petiolata infestation. A model of A. petiolata demography will allow us to test the effectiveness of single and multiple biological control agents on A. petiolata across its Michigan range by applying varied levels of mortality at different stages in A. petiolata’s life cycle. If the modeling effort predicts that single agent control will be effective, multiple introductions and their associated risks may be avoided.

In May 2004, we established a factorial study to determine the joint effects of herbivore browsing and A. petiolata on native plants in forest understories. Plots with and with out deer and turkey access and with our without A. petiolata were used to test the hypothesis that herbivores and A. petiolata negatively impact native plant communities, both separately and in concert. We marked 96 1 m2 permanent sampling quadrats in a high quality hardwood forest at the Edward Lowe Foundation’s Big Rock Valley in Cassopolis, MI. 64 of the plots were set out in discrete patches of A. petiolata, and 32 plots were set out in areas completely free of A. petiolata (GM 0). Half of the plots containing A. petiolata plants were randomly assigned to have GM clipped at the root crown, bagged, and removed from the site (GM-) and half were left undisturbed (GM+). 16 randomly selected plots from each A. petiolata treatment were enclosed by a 1.5 m diameter, 1.5 m high wire mesh fence to exclude deer and turkeys (Deer-). Half of the remaining plots in each treatment were randomly assigned to receive a semicircle of the same material as a sham fence (Deer+) or no fencing (Deer0) as a cage control. Number of A. petiolata seedlings and adults and percent coverage of all other vegetation by species were recorded in each plot in June 2004. Changes in vegetation over time are expected to indicate effects of herbivore disturbance and/or A. petiolata invasion.

11) Project Title: Survey of natural enemies of emerald ash borer, Agrilus planipennis (Coleoptera: Buprestidae) in Michigan and China

Investigators: Leah S Bauer^1,2, Houping Liu², Deborah L. Miller¹, Ruitong Gao^3
1 USDA Forest Service, North Central Research Station, E. Lansing, MI 48823
² Michigan State University, Department of Entomology, E. Lansing, MI 48824
³ Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, China

Contact: Houping Liu (liuho@msu.edu)

Project Description: The emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), a wood-boring insect indigenous to China, Japan, Korea, Mongolia, Russian Far East, and Taiwan, was identified as the cause of extensive ash (Fraxinus spp.) mortality throughout southeastern Michigan and southwestern Ontario in June 2002. Feeding of EAB larvae within the cambial region of ash trees disrupts the flow of nutritients, resulting in host tree death within 2-4 years. In 2002, regulatory agencies in the United States and Canada adopted a strategy of eradication for the emerald ash borer (EAB), Agrilus planipennis, in an effort to protect New World ash. Should eradication fail, however, conventional biological control will be needed to suppress the populations of this invasive buprestid. To this end, we are studying the natural enemies of EAB in Michigan and in China. In China, EAB is a periodic pest of their native ash, as well as two locally planted New World ash species: F. velutina and F. pennsylvanica.

We surveyed EAB natural enemies in a woodlot in Livonia, Michigan by sampling infested ash trees every two weeks from August 2002 to July 2003. Log sections from those trees were either dissected or incubated under laboratory conditions for insect natural enemies and entomopathogenic fungi. The most prevalent natural enemies found were five species of fungi, including Beauveria bassiana, Paecilomyces farinosus, Paecilomyces fumosoroseus, Verticillium lecanii, and Metarhizium anisopliae, with less than 2% individuals being infected. One egg parasitoid, Pediobius sp. (Eulophidae), was reared from 0.3% of EAB eggs collected in early July 2003. Seven potential larval parasitoids included Heterospilus sp. (Braconidae); Phasgonophora sulcata (Chalcidae); Balcha sp. and Eupelmus sp. (both in Eupelmidae). The most prevalent parasitoid was Balcha sp., a solitary ectoparasitoid of EAB larvae. Coleopteran predators include Enoclerus sp. (Cleridae), Catogenus rufus (Passandridae), and Tenebroides sp. (Trogossitidae); these predaceous beetles consume EAB during both larval and adult stages.

In north and northeastern China, ash trees in woodlots, cities, roadsides, and nurseries were surveyed for EAB and its natural enemies in Heilongjiang, Jilin, Liaoning, Hebei, Tianjin, and Shandong Provinces from late October and early November 2003. The previously reported Spathius sp. (Braconidae) was collected at two locations, with 1 to 50% of EAB parasitized. We also discovered an unknown gregarious endoparasitoid of EAB larvae in Changchun city of Jilin Province, and Benxi county of Liaoning Province, with a parasitism rate of 2.7 to 50% (H. Liu). Mature larvae, pupae, and adults were collected and later identified as Tetrastichus sp. (Eulophidae) (M. Gates, USDA ARS SEL and Dawei Huang, Institute of Zoology, Chinese Academy of Sciences, Beijing, China).

In 2004, we expanded our study of EAB natural enemies to include 14 diverse habitats throughout the infestation in southeastern Michigan. In cooperation with local foresters in China, we established research plots in Jilin and Liaoning Provinces to determine the species composition and seasonal abundance of natural enemies attacking EAB where it is native. The results of our 2004 studies are still pending.

12) Project Title: Studies on microbial insecticides for suppression of emerald ash borer

Investigators: Leah S Bauer^1,2, Houping Liu², Deborah L. Miller^1
1 USDA Forest Service, North Central Research Station, E. Lansing, MI 48823
² Michigan State University, Department of Entomology, E. Lansing, MI 48824

Contact: Houping Liu (liuho@msu.edu)

Project Description: The emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), native to northeastern Asia, was first found attacking various species of ash (Fraxinus spp.) in Michigan and Ontario in 2002. Infestations were then discovered in Ohio, Indiana, Maryland, Virginia due to the transport of infested nursery stock, firewood, timber, and natural spread. Larvae of EAB feed under the bark of ash trees, causing tree death within three to four years. Millions ash trees in southeastern Michigan and Ontario are dead and dying due to this invasive buprestid, and billions more ash trees throughout North America are at risk. Programs designed by regulatory agencies to eradicate localized infestations of EAB involve detection and removal of infested ash trees (Fraxinus spp.) and creation of an ash-free zone surrounding the epicenter. Conventional insecticides are being tested to aid in the eradication effort and to protect landscape ash trees, however, the use of such products is not an option in Michigan due to the extensive area infested by EAB, legal issues, and lack of public support. Due to the difficulty in identifying infested trees and the high rate of EAB movement, this invasive buprestid is likely to continue spreading in forests and parks throughout Michigan and surrounding areas. Clearly, methods are needed to manage EAB in North America. To this end, we are studying the efficacy of biopesticides formulated with isolates of Bacillus thuringiensis (Bt) and a product formulated with Beauveria bassiana var. GHA (Bb). Public acceptance remains high for the use of biopesticides due to good safety records and compatibility with other management strategies including biological control.

In 2003, we screened EAB adults with four registered Bt biopesticides, each with different Bt strains and host ranges. Mortality was observed for each product, but only at concentrations exceeding the maximum labeled rate. We are now cooperating with other Bt researchers to screen isolates and fractions of Bt for activity against EAB with the long term goal of developing a new Bt-based insecticide targeting EAB.

Beauveria bassiana var. GHA is the active ingredient of the biopesticide, BotaniGard®, registered for control of insect pests of forest and shade trees in 1999. We are evaluating the potential use of BotaniGard for suppression of EAB populations by homeowners and land managers. The two formulations of this product, BotaniGard ES (petroleum based) and BotaniGard O (vegetable oil) were equally virulent against EAB adults with LC50s of 4.9 and 4.7 spores/cm2, respectively; LT50s ranged from 4 to 10 days, depending on spore concentration. Laboratory and greenhouse studies showed that pre-emergent trunk sprays of BotaniGard were a promising method for control of EAB. In spring 2003, we applied BotaniGard to EAB-infested tree trunks prior to beetle emergence at the rate of 2 and 20 qts BotaniGard/acre in a plantation of 20-yr old ash trees in Ann Arbor. The trunks of treated and control trees were then caged, enclosing some epicormic shoots, and EAB were allowed to complete their life cycle within the cage. After death, EAB were cultured for fungal infection; at 0, 2, and 20 qts/acre, prevalence of B. bassiana infection among adults was 0%, 58.5%, and 83.0%, respectively. The maximum-labeled rate for BotaniGard is 17 qts/acre. In Oct 2003, we sprayed EAB-infested ash trees with 14 qts BotaniGard/acre to evaluate the impact on larvae inside infested ash tree trunks. These trees had visible cracks in the bark over EAB galleries, and we presumed BotaniGard may penetrate into the larval galleries via these bark cracks. In the winter, after tree dissection, we determined 10-20% of the larvae were infected with B. bassiana; no EAB larvae were infected in the controls. It is possible that higher levels of infection might be achieved if BotaniGard is applied to cracked tree trunks earlier in the fall, prior to EAB entering the sapwood to overwinter.

In 2004, we evaluated field persistence of B. bassiana GHA spores and the efficacy of Bt and B. bassiana GHA against EAB adults and larvae. Results of persistence study showed that B. bassiana GHA spores survived well under field conditions without significant decrease in pathogenicity, with a mortality of 78 to 100% observed for adults exposed to sprayed ash leaves 0 to 11 d after treatment. Log dissection and efficacy evaluation for Bt and B. bassiana GHA treatments in infested and un-infested ash plots are still ongoing.

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2003-04 Michigan Publications

Brewer, M. J. and N. C. Elliott. 2004. Biological control of cereal aphids and mediating effects of host plant and habitat manipulations. Ann. Rev. Entomol. 49: 219-242.

NCR-125. Relative impacts of natural enemy taxa on soybean aphid population regulation.

Costamanga, A.C., and D.A. Landis. 2004. Effect of Food Resources on Adult Glyptapanteles militaris and Meteorus communis (Hymenoptera: Braconidae), Parasitoids of Pseudaletia unipuncta (Lepidoptera: Noctuidae). Environ. Entomol. 128-137.

Isaacs, R., O'Neal, M.E., Szendrei, Z., and Tuell, J. (2004) Potential of ground covers for manipulating pest, predator, and pollinator populations in highbush blueberry. IOBC/wprs Bulletin 27: 17-24.

Landis, D.A., D.C. Sebolt, M.J. Haas, and M. Klepinger. 2003. Establishment and Impact of Galerucella calmariensis L. (Coleoptera: Chrysomelidae) on Lythrum salicaria L. and associated plant communities in Michigan. Biological Control. 28:78-91.

Landis. D.A., T.B. Fox, A.C. Costamagna. 2004. Impact of multicolored Asian lady beetle as a biological control agent. The American Entomologist. 50: 153-54.

Liu, H-P., L. S. Bauer, R-T. Gao, T-H. Zhao, T. R. Petrice, and R. A. Haack. 2003. Exploratory survey for the emerald ash borer, Agrilus planipennis (Coleoptera: Buprestidae), and its natural enemies in China. The Great Lakes Entomologist. 36(3&4): 191-204 (published in 2004).

Menalled, F.D., A.C. Costamagna, P.C. Marino, and D.A. Landis. 2003. Temporal variation in the response of parasitoids to agricultural landscape structure. Agric. Ecosyst. Environ. 96: 29-35.

Menalled, F.D., D.A. Landis, and L.E. Dyer. 2004. Research and extension supporting ecologically based IPM systems. Journal of Crop Improvement 12 (1/2): 153-174.

Noma, T., M. J. Brewer, K. S. Pike, and S. D. Gaimari. Hymenopteran parasitoids and dipteran predators of Diuraphis noxia in the west-central Great Plains of North America: species records and geographic range. Biocontrol: in press.

O'Neal, M.E., C.D. DiFonzo, D. A. Landis, and D. Meek. 2002 (appeared fall 2003). Monitoring Diabrotica virgifera virgifera (LeConte) in Michigan soybean fields and subsequent adult emergence in rotated and continuous cornfields. Great Lakes Entomologist. 35: 173-181.

O'Neal, M.E., D.A. Landis, J.R. Miller, and C.D. DiFonzo. 2004. Corn phenology influences Diabrotica virgifera virgifera (LeConte) emigration and visitation to soybean. Environ. Entomol. 33: 35-44.

O'Neal, M.E., Mason, K.S., and Isaacs, R. (in press) Seasonal abundance of ground beetles in highbush blueberry (Vaccinium corymbosum) fields and response to a reduced-risk insecticide program. Environ. Entomol.

O'Neal, M.E., Zontek, E.L., Szendrei, Z., Landis, D.A., and Isaacs, R. (in press) Ground predator abundance affects prey removal in highbush blueberry (Vaccinium corymbosum) fields and can be altered by aisle ground covers. Biocontrol.

Rutledge, C.E., R.J. O’Neil, T.B. Fox, and D.A. Landis. 2004. Soybean aphid predators and their use in IPM. Annals Ent. Soc. Am. 97: 240-248.

Sebolt, D.C., and D. A. Landis. 2004. Arthropod Predators of Galerucella calmariensis L. (Coleoptera: Chrysomelidae): An assessment of biotic interference. Environ. Entomol. 356-361.

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