Emerald ash borer (Agrilus planipennis) is an invasive pest that has killed millions of ash trees (Fraxinus spp.) in the USA since its first detection in 2002. Although the current methods for trapping emerald ash borers (e.g., sticky traps and trap trees) and visual ground and aerial surveys are generally effective, they are inefficient for precisely locating and assessing the declining and dead ash trees in large or hard-to-access areas. This study was conducted to develop and evaluate a new tool for safe, efficient, and precise detection and assessment of ash decline and death caused by emerald ash borer by using aerial surveys with unmanned aerial systems (a.k.a., drones) and a deep learning model. Aerial surveys with drones were conducted to obtain 6174 aerial images including ash decline in the deciduous forests in West Virginia and Pennsylvania, USA. The ash trees in each image were manually annotated for training and validating deep learning models. The models were evaluated using the object recognition metrics: mean average precisions (mAP) and two average precisions (AP50 and AP75). Our comprehensive analyses with instance segmentation models showed that Mask2former was the most effective model for detecting declining and dead ash trees with 0.789, 0.617, and 0.542 for AP50, AP75, and mAP, respectively, on the validation dataset. A follow-up in-situ field study conducted in nine locations with various levels of ash decline and death demonstrated that deep learning along with aerial survey using drones could be an innovative tool for rapid, safe, and efficient detection and assessment of ash decline and death in large or hard-to-access areas.

Black cherry is an ecologically important high-value wood. A decline of its regeneration has been reported in the USA, which could be associated with a lack of pollination. This study was conducted to identify insects visiting black cherry flowers, to determine whether insects captured on the flowers carry black cherry pollen and to identify the volatile organic compounds (VOCs) emitted by flowers of black cherry. A two-year insect survey was conducted before, during and after the black cherry bloom. A total of 9533 insects were captured in traps and Diptera was the most abundant (64.1%). Significantly more insects in Diptera, Lepidoptera and Thysanoptera were captured in the traps installed in the canopy than those on the ground, and Anthalia bulbosa (Diptera: Hybotidae) was the dominant species. Electron microscopy analyses demonstrated that insects captured in the canopy indeed carried black cherry pollen. Black cherry flowers emitted a VOC blend that is composed of 34 compounds and dominated by β-ocimene and several phenylpropanoids/benzenoids. This floral VOC profile is similar to that of other pollinator-dependent Prunus species. This study reports pollinator insects and associated VOCs, for the first time, that could play a significant role in the pollination and regeneration of black cherry.

Over the last decade, the Allegheny National Forest (ANF) in the USA has experienced issues with the regeneration of black cherry (Prunus serotina). This study was conducted to investigate the effects of silvicultural treatment on the insect communities that may affect black cherry pollination and regeneration. We conducted a 2-year study to compare the abundance, richness, and diversity of insects in unmanaged, shelterwood seed-tree, and shelterwood clear-cut stands. Using pan traps, we sampled insects at the ground level and in the canopies of flowering mature black cherry trees. The results of this study showed significant increases in the abundance of insects captured in shelterwood seed-tree stands and in species richness and diversity of insects captured in the canopy of black cherry in shelterwood removal stands, indicating that silvicultural treatment affected the insect community significantly. The dominant insect order was Diptera (true flies, 72.91%, n = 12,668), and Anthalia bulbosa (Diptera: Hybotidae) was the dominant species comprising 33% of all insects found in the canopy of flowering black cherry. The findings in this study could help land managers in managing black cherry for its pollination and natural regeneration.

The invasive shrub glossy buckthorn (Frangula alnus) has been progressively colonizing the Northeastern United States and Southeastern Canada for more than a century. To determine the dominant arthropod orders and species associated with F. alnus, field surveys were conducted for two years across 16 plots within the Allegheny National Forest, Pennsylvania, USA. Statistical analyses were employed to assess the impact of seasonal variation on insect order richness and diversity. The comprehensive arthropod collection yielded 2845 insects and arachnids, with hemipterans comprising the majority (39.8%), followed by dipterans (22.3%) and arachnids (15.5%). Notably, 16.2% of the hemipterans collected were in the immature stages, indicating F. alnus as a host for development. The two dominant insect species of F. alnus were Psylla carpinicola (Hemiptera: Psyllidae) and Drosophila suzukii (Diptera: Drosophilidae); D. suzukii utilized F. alnus fruits for reproduction. Species richness and diversity exhibited significant variations depending on the phenology of F. alnus. The profiles of volatile compounds emitted from the leaves and flowers of F. alnus were analyzed to identify factors that potentially contribute to the attraction of herbivores and pollinators. The results of our study will advance the development of novel F. alnus management strategies leveraging the insects associated with this invasive species.

Background: The periodical cicadas of Brood X (Hemiptera: Cicadidae) emerged in the summer of 2021, shortly after several thousand trees were planted throughout the District of Columbia, USA, during 2020 to 2021. There was concern that the millions of cicadas would negatively impact recently planted trees. This presented an opportunity to assess the impacts of periodical cicadas on an urban tree planting program. Methods: Newly planted trees were surveyed, with field inspections and remote sensing techniques, for evidence of cicada egg laying and twig damage related to tree genus and location within trees and throughout the District. Results: There were significant differences in egg-laying behavior among 10 tree genera, with the most damage observed in Acer and Nyssa . Egg laying occurred most often in scaffold and lateral branches. Egg-laying intensity was positively correlated with percent foliage lost. There was little evidence of cicada impacts on tree health as tree condition was unrelated to egg-laying intensity. Survival of the 2020 to 2021 tree cohort was similar to previous years without a large-scale cicada emergence. Remote sensing was unsuccessful in differentiating cicada caused damages from other damage. Conclusions: Municipal urban forestry departments facing a large periodical cicada emergence may continue tree planting campaigns and avoid damage to new trees by choosing less preferred genera. Although useful, remote sensing products are not currently at the point where a non-remote sensing specialist can acquire and utilize these tools for identifying cicada damage. Field surveys are recommended for accurate delimitation of cicada activity in urban settings.