Pawpaws: Ohio’s State Fruit

Dr. Don Cipollini takes us on a walk through the Wright State University Woods and his own backyard to talk about Ohio\u27s state fruit, the Pawpaw and the trees that grow it. He discusses how to grow pawpaw, the biology of the tree, and how you can use and eat the fruit it produces

The Persistence of Blue Ash in the Aftermath of Emerald Ash Borer May Be Due to Adult Oviposition Preferences and Reduced Larval Performance

We examined the health of mature blue ash, Fraxinus quadrangulata, in two forests in southwestern Ohio in relation to that of mature white ash, F. americana, and examined the potential importance of oviposition preferences and larval resistance in the persistence of blue ash. Both blue ash and white ash were largely unaffected by emerald ash borer in 2012. By 2018, nearly 90% of the blue ash trees observed in these forests had full or nearly full canopies, as opposed to less than 20% of the white ash encountered in our studies. In 2021, blue ash maintained a similar degree of canopy health as in 2018, but no standing live mature white ashes remained. Bark removals revealed no current or past larval feeding attempts in blue ash in 2018 or 2021, except for one attacked and killed tree in 2018. All white ash trees examined were attacked. In a laboratory bioassay with cut stems, emerald ash borer larvae fed less and grew significantly more slowly on blue ash than on white ash. Both reduced larval performance and reduced adult oviposition likely contribute to the persistence of blue ash in forests devastated by emerald ash borer

Biogeographic Variation in Resistance of the Invasive Plant, Alliaria Petiolata, to a Powdery Mildew Fungus and Effect of Resistance on Competitive Dynamics

Garlic mustard is an invasive Eurasian biennial that has spread throughout the eastern United States and southern Canada. Populations of this plant vary in their susceptibility to Erysiphe cruciferarum, a causal agent of powdery mildew disease in Brassicaceous plants. We examined whether there were biogeographic patterns in the distribution of resistance in invasive North American and native European populations of this plant. We grew plants from 78 invasive and 20 native populations and screened them for powdery mildew resistance in the greenhouse. We found that populations were mostly monomorphic for either resistance or susceptibility but that some polymorphic populations were found from both continents. The proportion of populations showing resistance versus susceptibility was similar in both Europe and North America. Within continents, the spatial distribution of resistant and susceptible populations did not deviate significantly from random. We also examined whether the possession of the resistance trait alter intraspecific competitive dynamics. In two trials, we competed plants from resistant and susceptible populations in a target-neighbor design in the presence and absence of powdery mildew inoculum and examined the growth of the target plant. Target plants from resistant populations were overall larger than target plants from susceptible populations. Target plants were overall larger when grown in competition with susceptible neighbors. Further, resistant target plants showed a greater degree of release from competition when grown with a susceptible neighbor versus a resistant neighbor than the degree of release shown by susceptible target plants. This suggests a benefit of possessing the resistance trait with little apparent costs which should promote selection for this trait within plant populations

White Fringetree, Chionanthus virginicus, As a Novel Larval Host for Emerald Ash Boer

Emerald ash borer is an invasive Asian pest of ash species in North America. All North American species of ash tested so far are susceptible to it, but there are no published reports of this insect developing fully in non-ash hosts in the field in North America. I report here evidence that EAB can attack and complete development in white fringetree, Chionanthus virginicus L., a species native to the southeastern U.S. that is also planted ornamentally

Chemical Defenses in Garlic Mustard (Alliaria petiolata) and their Potential Role in Species Interactions in Forest Understories

Garlic mustard [Alliaria petiolata [(M. Bieb) Cavara & Grande; Brassicaceae] is a European native biennial herb, first recorded on Long Island, NY in the 1860s, and is expanding rapidly in northeastern and midwestern forests in the U.S. and in southern Canada. Garlic mustard flourishes in moist woodlands with moderate exposure to light, but it can grow in a diversity of other habitats. It is found in natural areas, woodlots, and along edges of agricultural fields and lawns throughout North America. Several life history traits likely contribute to the invasiveness of this species. It has a high inbreeding rate and can produce numerous seeds. It exhibits remarkable morphological plasticity to local environmental conditions. It can exude allelopathic chemicals (glucosinolates and their hydrolysis products) that can reduce seed germination and growth of some species, and that can affect mycorrhizal potential of soils. Garlic mustard has been shown to outcompete some ecologically and commercially important hardwoods in short-term experiments, and its presence in natural areas is associated with reduced native herb abundance and diversity. Garlic mustard can also negatively impact salamander populations that rely on litter dwelling animals for food, and it can endanger populations of the rare butterfly Pieris virginiensis by serving as an oviposition site by adults on which larvae can not survive. Because of its known or potential negative impacts in natural and agricultural ecosystems, garlic mustard is an important target for chemical and biological control efforts

The Sign and Strength of Plant-Soil Feedback for the Invasive Shrub, Lonicera maackii, Varies in Different Soils

Plants alter soil characteristics causing changes in their subsequent growth resulting in positive or negative feedback on both their own fitness and that of other plants. In a greenhouse study, we investigated whether the sign and strength of feedback changed across two distinct soil types, and whether effects were due to shifts in biotic or abiotic soil traits. Using soils from two different locations, we examined growth of the exotic invasive shrub, Lonicera maackii and the related native shrub, Diervilla lonicera, in unconditioned soils and in soils conditioned by previous growth of L. maackii, D. lonicera, and Fraxinus pennsylvanica. In a sandy acidic soil, L. maackii showed positive feedback in unsterilized soils, but its growth decreased and positive feedback became negative with sterilization in this soil. In a loamy circumneutral soil, L. maackii displayed neutral to negative feedback in unsterilized soils, but sterilization significantly increased growth in all conditioning treatments and caused feedback to become strongly negative. Native D. lonicera displayed negative feedback in unsterilized soil of both the sandy and loamy types, but sterilization either eliminated or reversed feedback relationships. Soil conditioning by L. maackii and F. pennsylvanica had very similar feedbacks on L. maackiiand D. lonicera. While some abiotic soil traits varied across soil types and were affected by conditioning, soil biota sensitive to sterilization were apparently important mediators of both positive and negative feedback effect

Habitat Assessment and Conservation Status of Endangered Northeastern Bulrush

Scirpus ancistrochaetus (Northeastern Bulrush) is a federally endangered sedge that grows in temporary wetlands. We performed surveys of 90 wetlands in Pennsylvania, Maryland, West Virginia, and Virginia, measuring areal extent, stem density, and number of flowering stems of Northeastern Bulrush. We also measured percentage of tree canopy closure, presence of threats, and size of wetland. Percentage of tree canopy closure was negatively correlated with wetland area, percentage of wetland area occupied by North-eastern Bulrush, total number of stems, stem density, and percentage of flowering stems. Wetland area was positively related to percentage of flowering stems and had a tendency to be positively related to stem density, likely in part due to larger wetlands having lower tree canopy closure. Invasive Phalaris arundinacea (Reed Canarygrass) and Microstegium vimineum(Japanese Stiltgrass) were present at 7% and 21% of the wetlands, respectively. Odocoileus virginianus (White-tailed Deer) and Ursus americanus (Black Bear) damage were present in 38% and 17% of wetlands, respectively. Modification of habitat was noted at 27% of wetlands. For wetlands with previous data on population size, 14% had increased, 34% were stable, 25% had decreased, and 27% were absent or had severely decreased. Our recommendations for management include reducing tree canopy closure with control of invasive species and White-tailed Deer where needed

A Review of Garlic Mustard (Alliaria petiolata) as an Allelopathic Plant

Alliaria petiolata is a widespread biennial herb from Eurasia that is one of the most recognizable invasive plants of forests in the eastern United States and southern Canada. After two decades of intensive study on its physiology, ecology, and impacts, this plant has come to be known in both the scientific and gray literature as an allelopathic plant capable of exerting negative, chemically mediated effects on plants and microbes in its environment. A critical review of the literature reveals that there is evidence both supporting and failing to support this assertion, and that conclusions can be affected greatly by the experimental approaches taken, the target species examined, the sources of allelopathic inputs, and environmental factors. The objective of this review is to provide a history of allelopathy research in A. petiolata, describing the various approaches that have been taken and conclusions drawn, and to summarize the current standing of A. petiolata as an allelopathic plant using the most ecologically relevant data on this phenomenon. Finally, we discuss the degree to which allelopathy, versus other mechanisms, may contribute to the invasive success of this plant

Habitat Assessment and Conservation Status of Endangered Northeastern Bulrush

Scirpus ancistrochaetus (Northeastern Bulrush) is a federally endangered sedge that grows in temporary wetlands. We performed surveys of 90 wetlands in Pennsylvania, Maryland, West Virginia, and Virginia, measuring areal extent, stem density, and number of flowering stems of Northeastern Bulrush. We also measured percentage of tree canopy closure, presence of threats, and size of wetland. Percentage of tree canopy closure was negatively correlated with wetland area, percentage of wetland area occupied by North-eastern Bulrush, total number of stems, stem density, and percentage of flowering stems. Wetland area was positively related to percentage of flowering stems and had a tendency to be positively related to stem density, likely in part due to larger wetlands having lower tree canopy closure. Invasive Phalaris arundinacea (Reed Canarygrass) and Microstegium vimineum(Japanese Stiltgrass) were present at 7% and 21% of the wetlands, respectively. Odocoileus virginianus (White-tailed Deer) and Ursus americanus (Black Bear) damage were present in 38% and 17% of wetlands, respectively. Modification of habitat was noted at 27% of wetlands. For wetlands with previous data on population size, 14% had increased, 34% were stable, 25% had decreased, and 27% were absent or had severely decreased. Our recommendations for management include reducing tree canopy closure with control of invasive species and White-tailed Deer where needed

A Review of Garlic Mustard (Alliaria petiolata) as an Allelopathic Plant

Alliaria petiolata is a widespread biennial herb from Eurasia that is one of the most recognizable invasive plants of forests in the eastern United States and southern Canada. After two decades of intensive study on its physiology, ecology, and impacts, this plant has come to be known in both the scientific and gray literature as an allelopathic plant capable of exerting negative, chemically mediated effects on plants and microbes in its environment. A critical review of the literature reveals that there is evidence both supporting and failing to support this assertion, and that conclusions can be affected greatly by the experimental approaches taken, the target species examined, the sources of allelopathic inputs, and environmental factors. The objective of this review is to provide a history of allelopathy research in A. petiolata, describing the various approaches that have been taken and conclusions drawn, and to summarize the current standing of A. petiolata as an allelopathic plant using the most ecologically relevant data on this phenomenon. Finally, we discuss the degree to which allelopathy, versus other mechanisms, may contribute to the invasive success of this plant