Response of Chinese Tallow (Triadica sebifera) and Coexisting Natives to Competition, Shade, and Flooding

A greenhouse experiment was designed to determine the interactive effect of light, flooding, and competition on the growth and performance of Chinese tallow (Triadica sebifera [L.] Roxb.) and three tree species native to the southeastern United States: water tupelo (Nyssa aquatica L.), sugarberry (Celtis occidentalis L.), and green ash (Fraxinus pennsylvanica Marshall). The experiment used a factorial design that received two treatments: light (low irradiance or high irradiance) and flood (nonflooded and flooded) regimes. In the nonflooded and high irradiance treatment, changes in the growth (ground diameter, number of leaves, and total biomass) indicated that growth metrics of tallow were highest when growing with sugarberry and water tupelo but decreased when tallow was in competition with green ash. In contrast, competition with tallow reduced the height, net photosynthetic rate, stomatal conductance, and transpiration rate of water tupelo. The results showed that tallow had lower growth metrics when in competition with green ash at no apparent decrease in the growth of green ash except for growth rate. Our results suggest that tallow may be less competitive with certain native species and underplanting may be a possible opportunity for improving the success rates of native trees species establishment in areas prone to tallow invasion. Study Implications: Chinese tallow is a highly invasive tree species in the southeastern coastal states and in this study, we examined the growth and survival of tallow in competition with tree species native to the southeastern coastal states, USA. The growth of tallow differed greatly among native species in well-drained environments lacking forest overstory with lower growth metrics when grown with green ash but higher growth metrics when grown with water tupelo and sugarberry. Following density reduction treatments, we recommend management actions that promote the regeneration of native tree species to occupy the open vegetation canopy and suppress reestablishment of tallow.

Fungi from Galleries of the Emerald Ash Borer Produce Cankers in Ash Trees

The emerald ash borer (EAB, Agrilus planipennis) is a devastating invasive pest that has killed millions of ash trees in the United States and Canada. EAB was discovered in the US in 2002 and first reported in Minnesota in 2009. It attacks ash trees that are native to the United States, including Fraxinus americana (white ash), F. nigra (black ash) and F. pennsylvanica (green ash). It also attacks Chionanthus virginicus (white fringe tree). Seven species of fungi isolated and identified only from EAB-infested trees in a previous study as having the potential to cause cankers were used to test their pathogenicity in F. americana (white ash). The fungi used were Cytospora pruinosa, Diplodia mutila, Diplodia seriata, Paraconiothyrium brasiliense, Phaeoacremonium minimum, Phaeoacremonium scolyti, and Thyronectria aurigera. Two field experiments that used F. americana used two inoculation methods: woodchip and agar plug inoculations. Results indicated that all of the fungi tested caused cankers in varying amounts, as compared to the controls. The largest cankers were caused by D. mutila (270 mm2), C. pruinosa (169 mm2), and D. seriata (69 mm2). All fungi except for T. aurigera were re-isolated and sequenced to confirm Kochs’ postulates. Canker-causing fungi found in association with EAB galleries have the potential to contribute to tree dieback and mortality.

FOREST RECLAMATION COMPLEXES OF THE ROSSOSHANSKY DISTRICT OF THE VORONEZH REGION

Forest reclamation complexes in the Rossoshan district of the Voronezh region are mainly represented with the participation of white acacia, silver birch, green ash, common elm and Tatar maple. The area occupied by them in the agricultural landscape is 2009 hectares. In cultures of hanging birch at the age of 19 years with a change in width from 6.0 m to 15.0 m, there is a decrease in the preservation of species by 8.8% and a decrease in wind protection height by 16.5% with a plant density of 3334 pcs / ha and placement of 3 , 0 x 1.0 m. According to the growth of plantings, they are estimated as Ia class of bonitet. In mixed crops aged 34 years, consisting of fast-growing and accompanying species with a planting width of 16.0 m, the highest height is for drooping birch (20.1 m), the lowest for green ash (14.3 m). The safety of such breeds is 46.8% and 60.6%, respectively. Forest belts, represented by white acacia, drooping birch, Tatar maple at the age of 36 years, have a preservation of species of 38.3-55.2%. The drooping birch has the highest height (22.4 m). In artificial linear plantations, consisting of common elm, drooping birch, Tatar maple and green ash at the age of 38 years, the greatest preservation is observed in the Tatar maple (54.7%), the lowest in green ash (32.7%). The drooping birch has the greatest windproof height (20.6 m) and is estimated in growth according to the Ia class of bonitet. Each breed has certain ecological and biological properties.

Field Response of Green Ash (Fraxinus pennsylvanica) and Honey Locust (Gleditsia triacanthos) to Aminocyclopyrachlor1

Field trials were conducted to assess the impact of aminocyclopyrachlor on green ash (Fraxinus pennsylvanica Marshall) and honey locust (Gleditsia triacanthos L.) trees in an urban environment. Aminocyclopyrachlor is a relatively new, selective, plant-growth-regulator herbicide in the pyrimidine carboxylic acid family. Treatments were applied to Kentucky bluegrass (Poa pratensis L.) sod growing with and without trees present. Evaluations included determination of a safe spraying distance from target trees and the effect of application timing on tree response. This multi-year study showed that green ash was highly tolerant to aminocyclopyrachlor while honey locust developed severe injury in trees closest to applications. Honey locust trees up to 7 m (23 ft) from the tree trunk to the edge of the application displayed moderate to severe injury symptoms and fall treatment in October and November had the lowest tree injury compared to all other application timings. Honey locust trees exhibiting moderate to severe cosmetic injury would not be acceptable to landowners; recovery over time was minimal. Trees located 13 m (43 ft) away displayed no injury for any treatment timing. Soil analysis demonstrated that aminocyclopyrachlor dissipation was the same underneath green ash and honey locust trees, and that dissipation was faster in the presence of growing trees. Taken together, these results provide a basic groundwork necessary for improving aminocyclopyrachlor labels, and a better understanding of this herbicide's effect on certain woody species. Index words: Herbicide injury, aminocyclopyrachlor, herbicide fate, tree safety. Species used in this study: Green ash, Fraxinus pennsylvanica Marshall, honey locust, Gleditsia triacanthos L. Chemicals used in this study: Aminocyclopyrachlor.

Emerald Ash Borer Approaches the Borders of the European Union and Kazakhstan and Is Confirmed to Infest European Ash

Emerald ash borer (EAB), Agrilus planipennis, native to East Asia, is an invasive pest of ash in North America and European Russia. This quarantine species is a threat to ash trees all over Europe. Survey in ten provinces of European Russia in 2019–2020 showed that EAB had spread faster and farther than was previously thought. The new infested sites were first detected in St. Petersburg (110–120 km from the EU border: Estonia, Finland) and Astrakhan Province (50 km from the Kazakhstan border). The current range of EAB in Europe includes Luhansk Province of Ukraine and 18 provinces of Russia: Astrakhan, Belgorod, Bryansk, Kaluga, Kursk, Lipetsk, Moscow, Orel, Ryazan, Smolensk, St. Petersburg, Tambov, Tula, Tver, Vladimir, Volgograd, Voronezh, and Yaroslavl. Within these, only seven quarantine phytosanitary zones in five provinces are declared by the National Plant Protection Organization of Russia. EAB was not found in the regions along the Middle Volga: Mari El, Chuvash and Tatarstan republics, Nizhny Novgorod, Samara and Saratov provinces. The infested sites in St. Petersburg and in the Lower Volga basin are range enclaves separated from the core invasion range by 470 and 370 km, correspondingly. It is possible that new enclaves can appear in the cities of Eastern Europe and Kazakhstan far from the current known range. All previously known infestations in European Russia were in green ash (Fraxinus pennsylvanica), which was introduced from North America, and individual trees of European ash (F. excelsior). A first confirmed case of mass decline of several thousand of EAB-infested European ash trees in Moscow province is provided. Therefore, there is no more doubt that under certain conditions EAB can seriously damage native ash trees in European forests.

Another Look at Systemic Neonicotinoid Applications for Emerald Ash Borer Suppression

Emerald ash borer (EAB, Agrilus planipennis) is an invasive phloem feeder from East Asia that has killed millions of ash trees in North America. Currently, effective options for individual tree protection are limited to systemic insecticides, in particular neonicotinoids, which have come under increased scrutiny for their nontarget effects. In this study, green ash (Fraxinus pennsylvanica) trees were treated with two neonicotinoid insecticides, imidacloprid and dinotefuran, at full and half label rates based on trunk diameter to evaluate residues and efficacy. Analyzing the leaf, stem, and root tissues, there was no difference in insecticide residues between application rates within each tissue type. However, there were significantly higher residues of imidacloprid in root tissue compared to other plant tissues, and dinotefuran applied at the full label rate resulted in lower residues in stem phloem tissue. Additionally, insecticide-treated stems were artificially infested with EAB eggs to measure larval success (survival and growth). EAB larvae consumed less phloem in treated trees compared to untreated controls. These findings suggest that, in small-diameter ash, lower than label-recommended doses may be a viable component of an integrated management plan for EAB.

First Occurrence and Re-description of Aculus epiphyllus (Nalepa) (Acariformes: Eriophyoidea) from Fraxinus pennsylvanica in Europe

Aculus epiphyllus (Nalepa, 1892) is reported from green ash in Europe for the first time. Ash rust mite has never been found on green ash, and we therefore re-describe and illustrate the female and male, and describe the nymph. The species was collected from the underside of the leaflets of the introduced ash species, Fraxinus pennsylvanica Marshall (Oleaceae) in Hungary.