A Canker Barking at the Wrong Knee: Thyronectria austroamericana Septic Arthritis

The mold Thyronectria austroamericana is a plant pathogen that causes canker in honey locust tree. We describe the first case of this mold causing septic arthritis in humans.

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.

The research of the structure and content of the seed coat of Gleditsia and some changes in its structure during the swelling

The goal is to study the structure and content of the seed coat of Gleditsia triacanthos L. with a hard seed coat, and some changes in its structure when this seeds swell. Research methods. One of the main reasons for hard-seeding is the hard, waterproof seed skin. In practice, before sowing, solid seeds are subjected to various types of treatments: physical or chemical, which increases the permeability of the seed shell to water. The seeds were treated with acetone, provided that the suberin, which is part of the seed shell with a solid cover, is a highly polymer hydrophobic substance with mandatory component – saturated and unsaturated acidic triglycerides and triglycerides, and partially dissolves in a solution of acetone. The presence of lignified elements, suberin and polysaccharides in the seed coat of honey-locust was confirmed by IR spectra of the surface of the seed coat, as well as histochemical reactions. The structure and composition of the seed coat were studied on the example of seeds of honey-locust. The results. In the coat of the seed of honey-locust there are identified three major layers with different physical-chemical and mechanical properties that vary with their functions. The cells of the epidermis of the seed coat of honey-locust have a thin shell with partial lignification. The hypoderm consists of cells impregnated with the hydrophobic substance suberin, whose shape is elongated parallel to the surface and provides a tight coupling between them. The parenchyma is the most powerful layer, consisting of parenchymal cells that are laid loosely. Scientific novelty. The research made it possible to find out the functions of individual layers of the Gleditsia seed coat, as well as to track changes in the structure of the seed coat when this seed swells.

Chemical Methods to Improve Seed Germination and Seedling Growth of Honey Locust (Gleditsia triacanthos L.)

The present study aimed to improve the seed germination and plantlet development of honey locust (Gleditsia triacanthos) using two types of edaphic substrate (peat and peat+sand) and different chemical substances. Breaking physical dormancy for some forest seeds is a challenge for researchers and forest managers in order to obtain a homogeneous germination on larger areas. Germination percentage of honey locust seeds were investigated by using different chemical treatments as follows: calcium hydroxide; concentrated solution of sodium 4-nitrophenolate; solution with a content of auxines; copper sulphate; potassium permanganate and concentrated sulfuric acid. The highest percentage of seed germination was obtained when the seeds were immersed in an aqueous solution of sulfuric acid (14%), followed by 12.5% (concentrated solution of sodium 4-nitrophenolate) and 12.3% (solution with a content of auxins). The lowest values (5%) were recorded when copper sulphate was used. Regarding the different types of studied substrates, the highest percentage of germination was obtained on peat + sand. As regards to seedling development, the highest values were obtained on the peat + sand substrate, with seeds treated with sulfuric acid (15.0 cm). The concentrated solution of sodium 4-nitrophenolate and solution with auxins recorded also high values, 15.2 cm, respectively 14.9 cm. The lowest values for seedling height (11 cm) was noted when seeds were treated with potassium permanganate.

Penestragania apicalis (Osborn & Ball, 1898) (Hemiptera: Cicadellidae, Iassinae) – a new invasive phytophages of honey locust in Eastern Europe

In July 2020, in the course of insect collection by light trapping within the city area of Donetsk, the invasive North American leafhopper Penestragania apicalis (Osborn & Ball, 1898) (Hemiptera: Cicadellidae: Iassinae) was first recorded for Eastern Europe. This is the third specialized phytophagous species of honey locust (Gleditsia triacanthos L.) introduced to Europe. The distribution of P. apicalis within Europe is still not known, this species is most likely to be widespread throughout the places of honey locust cultivation. The main vector of invasion of P. apicalis is unintended introduction with planting material and by way of self -spread of adults. The penetration of another one specialized phytophage of honey locust into the steppe zone of Eastern Europe requires additional researching of its distribution. Registration of P. apicalis at a considerable distance from the previously known habitat indicates its wide distribution in Europe. Since it is difficult to survey the crowns of tall trees, we recommend using light traps as the simplest and most effective method for leafhoppers detecting. The level of species harmfulness in the territory of its natural range and in Euro pe has not been assessed so far; therefore, the organization of work on a detailed study of its ecological and biological characteristics is required. The formation of a multispecies complex of specialized pests can have a negative impact on the plantings of honey locust in the zone of its introduction. In this regard, the state of the P. apicalis population requires constant monitoring along with other invasive phytophages of Gleditsia – leaf gall midge D. gleditchiae and seed-beetle M. dorsalis.