Silver Maple Research Articles

Survival and development of Lycorma delicatula (Hemiptera: Fulgoridae) on common secondary host plants differ by life stage under controlled conditions.

Host range assessment for emerging invasive insects is a vital step toward fully defining the issues the insect may pose. Spotted lanternfly (SLF) is an invasive species that is rapidly expanding its presence in the United States. The primary hosts facilitating this spread are tree of heaven, a plant from SLF's native range, and the economically important winegrape. Black walnut is also implicated as an important and common host plant. This study investigated the survival and development of SLF on diets that included a variety of crop host plants in the presence or absence of tree of heaven. The following plant species, 'Honeycrisp' apple, 'Reliance' peach, silver maple, and tree of heaven were paired with winegrape or black walnut throughout the study. SLF had strong development and high survival on a diet of winegrape alone, and winegrape or black walnut paired with tree of heaven. Survival parameters were reduced with all other plant pairings. In particular, SLF in the winegrape and peach diet treatment did not develop past the third nymphal instar. A second experiment evaluated the survival of early and late instar nymphs and adult SLF life stages on three specialty crops - 'Cascade' hops, muscadine grapes, and kiwifruit over a two-week period. Nymphs survived longer than adults, with survival of first and second instar nymphs on hops not differing from the control tree of heaven treatment. The adult stage survived best on kiwi and muscadine grape. Our results show tree of heaven and winegrape were the only single plant diets evaluated that are sufficient for complete SLF development, while other host plants may require additional host or hosts of sufficient nutritional quality for SLF survival.

Corrigendum for PM 7/149 (1) Anoplophora glabripennis and Anoplophora chinensis

Corrigendum for <scp>PM</scp> 7/149 (1) <i>Anoplophora glabripennis</i> and <i>Anoplophora chinensis</i>

МОНІТОРИНГ ПОСУХОСТІЙКОСТІ ІНТРОДУКОВАНИХ ВИДІВ ВИСОКОРОСЛИХ ДЕРЕВПІСЛЯ ЗМІНИ КЛІМАТИЧНИХ УМОВ УРБОПРОСТОРІВ

Background. Landscaping of urban environments significantly mitigates the negative effects of "urban heat islands", which in turn has a positive effect on many aspects of human life. Therefore, the purpose of our research was to identify droughttolerant rare and decorative species of woody plants with further recommendation for their inclusion in the ecosystems of the urban environment. Methods. For research, we selected from the collections of the Botanical Garden named after acad. O.V. Fomina 25 highly decorative species of trees with a height from 10 to 50 m, which come from temperate and continental climate zones. Among them, 14 species are uncommon and 11 species are widespread in mass culture in the Polissia and Forest-Steppe zone of Ukraine. The drought resistance test was conducted twice: in early June and also in early September. Relative drought resistance was assessed by following parameters: tissue hydration and water loss per unit time. Results. According to the results of the study, most of the 25 species of tall trees showed a high or average level of drought resistance. The most drought-resistant light-loving and shade-tolerant species were recommended. Species that may require additional care during cultivation (Phelodendron amurense and Styphnolobium japonicum) have been identified, which must be taken into account when landscaping urban areas. Conclusions. Among shade-tolerant trees, the following species can be recommended for cultivation in urban conditions as highly drought-resistant: Acer mandshuricum, Acer velutinum, Corylus colurna and Prunus padus. The following light-loving plants turned out to be the most drought-resistant: Liriodendron chinense, Ginkgo biloba, Acer saccharinum, Catalpa bignonioides, Catalpa fargesii and Tilia europea.

Javori (Acer L.) u ulicama centralnog dela Beograda - stanje i funkcionalnost

This research investigated the existing conditions and functionality of rows of maple trees (Acer L.) (which are traditionally used in our country for urban greening) in the streets that are the most frequent in terms of traffic intensity, ways of use and measures to maintain greenery (streets of the I and II order) on the territory of the municipality of Stari grad (Belgrade). In the investigated area a total of 39 streets of these categories were surveyed. Rows of maple trees are represented in 2 out of 15 streets of the I order and in 10 out of 24 streets of the II order. It was determined that the total number of trees belonging to the species of this genus is 735. Maple species recorded are: Acer pseudoplatanus L, Acer platanoides L, Acer campestre L. and Acer saccharinum L. The most represented species here is A. pseudoplatanus with a total of 442 (60.13%) trees, and an average vitality score of 3.6. They are followed by: A. platanoides with 213 (28.98%) recorded trees and an average vitality score of 3.5, A. campestre with 72 (9.80%) recorded trees and a rating of 3.1 and A. saccharinum with 8 (1.09%) trees and a rating of 2.3. One of the main factors in reducing the functionality of maple tree street rows in the study area was the application of the tree topping care measure.

Some characteristics of woody plants inhabited by Viscum album (Santalaceae) in the city of Kyiv

As a result of the study, a wide range of tree species parasitized by white mistletoe (Vіscum album) in the city of Kyiv, Ukraine, was identified. Some species, such as Quercus robur, Ulmus pumila, and Alnus glutinosa, remained uninfested even in the case of a high degree of infestation of surrounding trees. It has been found that among the infested plants only 4.34% of deciduous species and 5.05% of conifers demonstrated a severe damage caused by the hemiparasite (more than 20 plants of V. album in one crown). The largest number of trees and the highest level of damage were observed for Acer saccharinum, A. platanoides, Salix alba, Robinia pseudoacacia, Populus nigra, Tilia cordata, and Betula pendula aged in average 45–50 years. In the study of genetic characteristics of affected and unaffected by V. album trees of Pinus sylvestris at the molecular level by TBP markers, no differences have been revealed.

Impacts of short-term feeding by spotted lanternfly (Lycorma delicatula) on ecophysiology of young hardwood trees in a common garden.

Spotted lanternfly (SLF; Lycorma delicatula White; Hemiptera: Fulgoridae) invaded the US from Asia and was first detected in 2014; currently, populations have established in 14 states primarily in the Northeast and Mid-Atlantic. It feeds voraciously on phloem sap from a broad range of host plants, with a preference for tree of heaven (Ailanthus altissima [Sapindales: Simaroubaceae]), grapevines (Vitis spp. [Vitales: Vitaceae]), and several common hardwood tree species. We evaluated the impacts of fourth instars and adults confined to a single branch or whole trees on gas exchange attributes (carbon assimilation [photosynthetic rate], transpiration and stomatal conductance), selected nutrients, and diameter growth using young saplings of four host tree species planted in a common garden. In general, the effects of adults on trees were greater than nymphs, although there was variation depending on tree species, pest density, and time post-infestation. Nymphs on a single branch of red maple (Acer rubrum [Sapindales: Sapindaceae]), or silver maple (Acer saccharinum [Sapindales: Sapindaceae]) at three densities (0, 15, or 30) had no significant effects on gas exchange. In contrast, 40 adults confined to a single branch of red or silver maple rapidly suppressed gas exchange and reduced nitrogen concentration in leaves; soluble sugars in branch wood were reduced in the fall for silver maple and in the following spring for red maple. Fourth instars confined to whole silver maple trees reduced soluble sugars in leaves and branch wood, and reduced tree diameter growth by >50% during the next growing season. In contrast, fourth instars in whole tree enclosures had no effects on black walnut (Juglans nigra [Fagales: Juglandaceae]). SLF enclosed on tree of heaven at 80 adults per tree suppressed gas exchange after two weeks of feeding, but did not alter non-structural carbohydrates, nitrogen concentrations, or tree growth. Results suggest that moderate to heavy feeding by SLF on young maple saplings may impair tree growth, which could have implications for production nurseries and forest managers.

Silver Maple (Acer saccharinum L.) Leaf: A Potential Source of Antibacterial Compounds to Control Phytopathogenic Bacteria in Horticulture Crops

In this study, a crude ethanolic extract made of silver maple (Acer saccharinum L.) leaves (SML) was evaluated for antibacterial activity against the phytopathogenic bacteria Clavibacter michiganensis subsp. michiganensis, Pseudomonas syringae pv. tomato, and Xanthomonas fragariae. The extract was shown to cause important inhibition zones against the three bacteria in the disc diffusion assays, revealing its antibacterial activity. The minimal inhibitory concentration (MIC) of the extract was determined thereafter for each bacterium. The extract showed the same MIC value (1.56 mg·mL−1) for the three bacteria. Using a semipreparative high-performance liquid chromatography system, crude ethanolic SML extract was divided in 15 fractions and each fraction was tested for antibacterial activity against X. fragariae with the disc diffusion assay. Among the six fractions causing an inhibition zone, fraction 10 caused the largest inhibition. Fraction 10 was further analyzed by ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry. According to quadrupole time-of-flight mass spectrometry, the main peak of fraction 10 was identified as a galloyl-bis-HHDP-glucose (C41H28O26, 936.6454 g·mol−1) isomer, an ellagitannin known for antibacterial activity and for stimulating plant natural defenses. The study opens new avenues of research on the valorization of SML and on the control of plant diseases caused by bacteria in organic and conventional production of horticultural crops.

Major River Floodplain Forest Restoration: A Case Study in Western Massachusetts

Although efforts to restore floodplain forests are becoming more popular in the northeastern United States, best management practices are not well defined. In this study, we demonstrate the success of a planting effort in western Massachusetts to increase the extent of a floodplain forest along the Housatonic River. Over 1700 floodplain-adapted tree saplings were planted in an old field and in two hayfields at Bartholomew's Cobble, a property located in Sheffield, Massachusetts, and individually tagged to follow their growth and survival. Planted trees had relatively high rates of survival over a 6 y period, especially the two most commonly planted tree species: silver maple (Acer saccharinum, 42.5% survival) and boxelder (Acer negundo, 71.7%), although plantings were more successful in the old field compared to the two hayfields. Tree dbh after 6 y differed across fields for silver maples and boxelders with those planted within the old meadow significantly larger than those planted into hayfields (silver maple dbh 9.8 cm old field vs. 6.5–6.6 cm hayfields; boxelder dbh 10.4 cm old field vs. 4.4–6.6 cm hayfields). By documenting which floodplain-adapted tree species were successful in establishing under which conditions, our observational study provides valuable insights for future restoration efforts.

INVASIVE CYCLE AND ASSESSMENT OF THE DEPTH OF INVASION OF REPRESENTATIVES OF DENDROFLORA OF UKRAINE IN THE SOME ECOSYSTEMS BY EUROPEAN MISTLETOE (VÍSCUM ÁLBUM L.)

Research is related to the biology and ecology of white mistletoe (Víscum álbum L.), with an analysis of its impact on the dendroflora of natural and artificial ecosystems. The sequence of stages of the invasive cycle of mistletoe, starting from the stage of infection, the intensity of the invasion (the degree of its spread in the crown), the suppression of host trees, their death and biodegradation, as well as the mechanism of these processes. These stages have different durations in different species. A comparison of the full cycle of mistletoe infection for those species that are most often infected in Polissya, Eastern Podillya and in the coastal areas of the right bank of the Dnieper. The most sensitive species to the invasion were the following: Populus nigra L., Populus balsamifera L., Tilia cordata Mill, Salix babylonica L., Salix fragilis L., Juglans nigra L. and Juglans cinerea L., Sorbus aucuparia L., Betula pendula Roth , Acer saccharum Marshall, Acer saccharinum L., Fraxinus excelsior L. The intensity of the invasion by mistletoe also takes into account the degree of suppression aforementioned and some other species, have become particularly threatening today, so it requires finding ways to solve this biological and environmental problem. However, a number of tree species can resist to the spreading of mistletoe even under invasion due to mechanisms that ensure their high resistance, among them Populus pyramidalis Rozier, hybrids of poplars, Quércus rúbra L, some others. A number of species are able to resist to mistletoe spreading even under their conditions of infection due to the presence inner mechanisms that ensure their relatively high resistance to this parasite, among them: Populus pyramidalis Rozier, its hybrids, Quércus rúbra L., Prunus avium L., Prunus cerasifera Ehrh. A significant number of dendroflora species are outside of the influence of mistletoe. It is indicates on existing specific biological barriers which block following spreading and adaptation among Víscum album L. populations. The concept of resistance and sensitivity to mistletoe of representatives of dendroflora is offered. The algorithm for determining the tention of invasion by Víscum album, the processes of suppression, death and subsequent biodegradation of affected trees is optimized. The classification of the nature of the interaction of mistletoe and host trees is carried out. Strong invasion of mistletoe white require mutuals special efforts of scientists and state for restriction its spreading.

Interactive effects of biochar and N-fixing companion plants on growth and physiology of Acer saccharinum

The use of biochar with N-fixing species has been shown to enhance productivity of agricultural systems, both in N-fixing crops, as well as in mixed-species systems. Here we investigate the potential for the use of a granulated mixed conifer biochar and a sugar maple biochar in combination with N-fixing companion plants in an urban forestry context. A factorial greenhouse experiment compared growth responses in silver maple (Acer saccharinum L.) saplings planted with two biochar types as soil amendments, alone and in combination with two N-fixing plant companions (Trifolium repens L. and Dalea purpurea Vent.). Both biochar types enhanced tree growth; however, a maple feedstock biochar resulted in greater increases than a granulated conifer-feedstock biochar. N-fixing companion species also increased tree growth, although the faster-growing Trifolium reduced soil moisture content and reduced sapling growth in the absence of biochar. The highest tree growth performance and total N uptake was obtained with a combination of both biochar and N-fixing plants, with a ~30 % increase in biomass compared to controls for the granulated conifer biochar, and a ~55 % increase for the maple biochar. We conclude that biochar additions in combination with N-fixing companion species have considerable promise in an urban forestry context, but that optimization of the system in terms of biochar type and species combination is an important consideration.

Native tree seedling growth and physiology responds to variable soil conditions of urban natural areas

Soils in urban natural areas can be highly variable due to legacies of land use change that include excavation of existing soils and dumping of construction debris or other anthropogenic materials. As cities undertake large‐scale tree planting efforts to sustain and increase forest cover, understanding how urban soil quality influences native tree seedling survival and performance is important. In a greenhouse setting we examined growth and physiology of native silver maple (Acer saccharinum), black birch (Betula lenta), red oak (Quercus rubra), and Canadian serviceberry (Amalanchier canadensis) seedlings planted in soils collected from locations across New York, NY, U.S.A. The soils were collected from areas currently undergoing forest restoration, representing a range of soil nutrient quality and anthropogenic disturbance. We measured seedling survival, height growth, leaf chlorosis, and chlorophyll fluorescence for two growing seasons, after which seedlings were harvested to assess biomass allocation and foliar chemistry. Selected variables were standardized and combined to create a seedling stress index. Overall, seedlings performed best in the least disturbed urban soils and had the poorest performance in the more highly disturbed, nutrient‐poor urban soil types and a greenhouse mix. Species × soil type interactions on physiological responses indicate that tree species may not respond to urban soil conditions consistently. Consequently, matching native tree species to soil type could help optimize establishment and growth of urban forest restoration projects. Seedling stress scores from the first growing season were correlated with second year height growth for three of four species, illustrating their utility for managers.

Silver Maple

Silver Maple

TREE SPECIES DIVERSITY IN TWO SMALL CITIES OF KYIV REGION, UKRAINE

The diversity of trees is an important factor in ensuring the sustainability of urban forests, but it has hardly been studied in small towns in Ukraine. This study examines the diversity of urban tree species in two small towns in the capital region of Ukraine. The results show that the richest species composition of Vyshgorod city in the adjoining the houses territories and in mini-parks. A total of 100 species and forms of trees and shrubs have been found in the city. 27 species of trees and shrubs are represented In Ukrainka city. Spiraea vanhouttei, Syringa vulgaris and the genus Spiraea are critical for Vyshhorod city. Acer saccharinum, Pinus sylvestris, Populus piramidalis, Betula pendula and Spiraea vanhouttei are critical for Ukrainka city. In contrast to Vyshhorod, where the distribution of trees by diameter is close to optimal, Ukrainka lacks young trees and exceeds the share of ''ripening'', which violates the guarantees of sustainable development of urban plantations. The methodology used in this study may allow practitioners to better assess the sustainability of urban tree plantations.

Usefulness of Tree Species as Urban Health Indicators.

We used the Air Pollution Tolerance Index (APTI), the amount of PM5 and PM10, and the elemental analysis of leaves to explore the sensitivity of tree species to air pollution. We assessed the tolerance of Robinia pseudoacacia, Acer saccharinum, Tilia × europaea, Acer platanoides, Fraxinus excelsior, Betula pendula, Celtis occidentalis, and Platanus × acerifolia to the amount of dust, APTI, and the elemental concentration of leaves. Leaves were collected in Debrecen (Hungary), which has a high intensity of vehicular traffic. The highest amount of PM (both PM10 and PM5) was found on the leaves of A. saccharinum and B. pendula. Our results demonstrated that A. saccharinum was moderately tolerant, while P. acerifolia was intermediate, based on the APTI value. There was a significant difference in the parameters of APTI and the elemental concentration of leaves among species. We found that tree leaves are reliable bioindicators of air pollution in urban areas. Based on the value of APTI, A. saccharinum and P. acerifolia, and based on PM, A. saccharinum and B. pendula are recommended as pollutant-accumulator species, while other studied species with lower APTI values are useful bioindicators of air pollution. The results support landscape engineers and urban developers in finding the best tree species that are tolerant to pollution and in using those as proxies of urban environmental health.

Performance and host association of spotted lanternfly (Lycorma delicatula) among common woody ornamentals

Lycorma delicatula (spotted lanternfly) has a broad host range with a strong preference for the invasive host plant from its native range, tree of heaven (Ailanthus altissima); it had long been speculated that L. delicatula could not develop or reproduce without access to tree of heaven. In 2019, we found that this assumption was incorrect, but fitness was reduced in the absence of A. altissima in that the number of egg masses laid was dramatically fewer for insects reared on suitable non-A. altissima host plants that had recently been established. We hypothesized that longer established, larger trees (of the same species) would improve the fitness of L. delicatula in the absence of tree of heaven. In spring 2020, we examined insect performance with and without access to A. altissima by tracking development, survival, host tree association and oviposition in large enclosures with trees planted two years prior to the study. Each enclosure included one each of Juglans nigra, Salix babylonica and Acer saccharinum along with either one A. altissima or one Betula nigra; these trees had twice the diameter of the same trees the previous year. We reared nymphs with and without access to A. altissima, released them into the corresponding large enclosures as third instars, and monitored them from early July 2020 through November 2020. We also determined whether lack of access to A. altissima by parents of L. delicatula have any fitness effects on offspring performance. To ensure adequate adult populations for comparing fecundity between treatments, third instars were released into the multi-tree enclosures due to high mortality in earlier instars that occurred in a similar study in 2019. Insect survival was higher and development faster with access to A. altissima. Third and fourth instar nymphs were most frequently observed on A. altissima when it was present, while adults were equally associated with A. saccharinum and A. altissima. In the absence of A. altissima, nymphs were most frequently found on S. babylonica, while adults were most often on A. saccharinum. Females with access to A. altissima deposited nearly 7-fold more egg masses than those without access to A. altissima, which is consistent with the difference in egg mass numbers between the two treatments the previous year; thus, our hypothesis was rejected. The offspring of parents that had been reared without access to A. altissima showed similar survival and development time from egg to adult as offspring from parents that never had access to A. altissima. These findings suggest that managers need to be aware that even in the absence of A. altissima in the landscape, several hardwood host trees can be utilized by L. delicatula to develop and reproduce, but fitness without A. altissima is likely to still be reduced.

Molecular identification of Anoplophora glabripennis (Coleoptera: Cerambycidae) and detection from frass samples based on real-time quantitative PCR

Anoplophora glabripennis (Motschulsky 1853) (Coleoptera: Cerambycidae), the Asian Longhorned Beetle, is native to temperate and subtropical areas of China and the Korean peninsula. Due to its wide range of host plants, it is considered among the most economically important invasive plant pests. The morphological identification of A. glabripennis larvae can be confirmed by DNA barcoding, but obtaining the specimens from infested trees can be a demanding and challenging task. Therefore, non-invasive diagnostic tools based on DNA extracted from frass samples can be of key importance in phytosanitary surveys. In this study, an in silico generated real-time quantitative PCR test was developed for the detection of A. glabripennis DNA from frass material, which is naturally extruded from larval tunnels through cracks in the bark. Specificity was confirmed against a wide range of other wood-boring insect species frequently encountered during phytosanitary surveys and inclusivity was demonstrated for different populations of A. glabripennis from all main European outbreak areas. The test proved sensitive and reliable in detecting A. glabripennis DNA extracted from woody frass material of Acer saccharinum and Aesculus hippocastanum at least up to the 100-fold dilution. Furthermore, the test allowed the molecular identification of any life stage of the insect, including eggs and young larvae, whose morphological identification is impossible or very challenging. This study provides a reliable and sensitive molecular tool to detect A. glabripennis DNA in woody frass material, thus allowing a non-invasive sampling approach.

A biomechanical model of leaf inclination angle oscillations after raindrop impact

Raindrop impact exerts a force on the leaf resulting in a decaying oscillation of the leaf inclination angle. Nondestructive measurements of leaf oscillations is important for predicting changes in leaf angles in the field based on morphometric properties of leaves. The objectives of this study were to determine if a second order impulse response could describe experimentally observed changes in leaf inclination angle, to determine if field measurable, nondestructive leaf traits significantly correlate with model parameters, and to determine if the model parameters were species-specific. This study examined leaf oscillations for three common species in Colorado, USA (Acer saccharinum, Quercus gambelii, and Ulmus pumila) due to two different raindrop sizes. The drop impact was created by releasing a single drop of known size from a known height. The resulting leaf motion was recorded using a high-speed video camera. The images were then processed to measure the leaf inclination angle as a function of time, and a model was used to fit the data. The model was evaluated for quality of fit to the data. The experimental data closely fit the modeled data, indicating that the impulse response appropriately predicts leaf oscillations after raindrop impact. Strong linear relationships existed between leaf mass and maximum change in leaf inclination angle after drop impact for both the experimental and the modeled data. The model parameters were also found to be species-specific. The oscillations in leaf inclination angle are accurately described with a second order impulse response. The parameters of the impulse response correlate with field measurable leaf traits and the parameters are species-specific. The data and approach in this study provided a nondestructive tool for the prediction of changes in leaf inclination angle for many broad-leaved species with diverse leaf morphometric properties.

Floodplain forest structure and the recent decline of Carya illinoinensis (Wangenh.) K. Koch (northern pecan) at its northern latitudinal range margin, Upper Mississippi River System, USA

Floodplain hardwood forests that exist on islands and immediately adjacent to channels along the Upper Mississippi River System (UMRS) are ecologically important due to high floral and faunal biodiversity. The recent decline and regeneration failure of hard mast species—e.g. Quercus spp. and Carya spp.—along the UMRS has been well documented, but causes of these trends have not been widely examined and are thus poorly understood. To investigate the mechanisms of this decline, we installed three 0.20-ha plots within the floodplain forests of the UMRS amongst communities known to contain the northernmost documented individuals of Carya illinoinensis (Wangenh.) K. Koch, a regionally imperiled, yet ecologically, economically, and culturally important hard mast species. Tree density (>5 cm dbh) averaged 355 stems ha−1 (n = 239, 12 representative species across 9 genera) and mean basal area was 77 m2 ha−1 across the three sites. Acer saccharinum L. was the most dominant species (49.0 m2 ha−1). The diameter distribution of trees demonstrated a negative exponential pattern, generally indicative of uneven-aged, regenerating forests. Over the past ca. 120 years, decadal-scale pulses of tree establishment across species show linkages with riparian engineering installments and flood and drought events. C. illinoinensis demonstrated a consistent establishment pattern since at least the 1860s through the 1950s, but experienced regeneration failure over the past ca. 50 years. Widespread ecological growth releases in C. illinoinensis are linked with known large-scale flood events along the UMRS (1965, 1993, 2001, 2011 CE). Correlation analysis revealed relationships between C. illinoinensis growth rings and drought, precipitation, maximum temperature, and river flow to be temporally unstable with an inflection point at the beginning of the lock and dam era (ca. 1930s–1940s). The coincidental decoupling of climate and flow variability with tree growth in the post-lock and dam era suggests that peripheral, disjunct populations of C. illinoinensis are sensitive to impacts from anthropogenic land and hydrologic modifications. Forest structure, disturbance history, and climate analyses demonstrate that without management intervention, C. illinoinensis will no longer have a significant presence within floodplain forests of the UMRS in the near future, contributing to loss in diversity. Direct forest restoration techniques, such as planting and creation of canopy gaps via regeneration-focused harvesting, are needed if C. illinoinensis is to return to historical abundance and distribution.

PRESENCE OF NORTH AMERICAN APHID DREPANAPHIS ACERIFOLIAE (THOMAS, 1878) (HEMIPTERA: APHIDIDAE: DREPANOSIPHINAE) IN SERBIA

The painted maple aphid, Drepanaphis acerifoliae (Thomas, 1878), is present on Acer saccharinum L. (silver maple) in Serbia. It was found for the first time in 2019 in parks in Novi Sad, and in 2020 it was registered in Belgrade. It is a North American species that has been extending its distribution in Europe since 1992. Serbia is the fourth European country in which it has been found, following Italy, Spain and Hungary. Drepanaphis acerifoliae was found to be present on all examined A. saccharinum L. trees where it is usually very numerous. It was not found on A. platanoides L., A. campestre L., A. pseudoplatanus L. or A. negundo L. The morphology of viviparous parthenogenetic females, oviparous females and males is presented, with original drawings and photos.

Effects of native leaf litter amendments on phosphorus mineralization in temperate floodplain soils

As phosphorus (P) losses from Midwestern crop fields degrade water quality in downstream water bodies, the assessment of natural P immobilization in floodplain soils is imperative to reduce P input to the Gulf of Mexico. While the organic C:P ratio of soil is widely accepted as an important indicator of P immobilization, roles of the quality/type of C sources (i.e., foliar C composition and degradability) on soil P dynamics are not clearly understood. The objective of this laboratory incubation study was to assess the influence of leaf residue of native trees (e.g., hackberry, and silver maple) on P reaction dynamics in floodplain soils as a function of C composition (i.e., carbonyl-, alkyl- and aromatic-C) and soil organic C:P ratios. Conventional wet chemical analyses and 31P NMR spectroscopy were used to understand changes in P speciation and phosphatase activities. During the incubation, at a soil organic C:P of ∼200, residues with low aromaticity promoted P mineralization, as evidenced by a sustained increase in labile inorganic P and decrease in microbial P. Conversely, residues with high aromaticity and hydrophobicity (i.e., silver maple) caused a decrease in labile inorganic P and increase in microbial P under the same soil organic C:P, indicating the dominance of P immobilization. At a soil organic C:P of 300, both sugar maple and silver maple promoted P immobilization. Mineralization rates were of lesser magnitude in the soils amended with silver maple, which interestingly contained the largest proportions of recalcitrant C and the highest ratios of aromaticity and hydrophobicity.