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This article discusses the occurrence of bleeding stem cankers and root rot in Morus alba, Pistacia atlantica, and Sterculia diversifolia trees in urban parks and gardens in eastern Sicily. The researchers isolated a homothallic Phytophthora species from the affected trees and confirmed its identity as Phytophthora multivora through phylogenetic analysis. The pathogenicity of the isolates was tested on saplings of the three tree species, resulting in leaf chlorosis and stem gummosis. This is the first report of P. multivora from Morus alba and as a pathogen of Pistacia atlantica and Sterculia diversifolia worldwide. The study emphasizes the importance of surveys in urban green areas. [Extracted from the article]

In this study, the medium-term evolution of some erosion channels (ephemeral gullies, EGs) initiated in a wheat-cultivated area on silty-clay-loam soils in central Sicily (Italy) in 1995 was studied over 18 years. The studied EGs showed a cyclic behaviour. They appeared during the rainy season, were erased from July to October by soil infill from areas adjacent to the channel using ordinary tillage equipment, and, in most years, they reappeared in the same position during the following rainy season. Between 1995 and 2013, some field surveys were conducted to measure the channel dimensions (length, depth, width, surface area and volume). The channel size evolved over time. The depth and width increased from 76% to 90% in different EGs, reaching a depth greater than 1 m and an upper width greater than 2 m. These dimensions interfere with conventional tillage operations, and farmers suspend their efforts to fill in the channels. At the same time, the study showed that the EG length increased until almost 2006 and decreased in more recent years due to natural infilling beginning in the downstream area of the watersheds where the gradient is less. The average infilling rate ranged from 1.1 to 4.3 m year −1 . The results, on the whole, show how, once formed, EGs evolve towards permanent channels (gullies) and then can be naturally filled if the soil management system and precipitation regime are invariant. [ABSTRACT FROM AUTHOR]

Research Highlights: Protected natural areas are a reservoir of Phytophthora species and represent the most suitable sites to study their ecology, being less disturbed by human activities than other environments. Background and Objectives: The specific objective of this study was to correlate the diversity and distribution of Phytophthora species with the vegetation in aquatic, riparian and terrestrial habitats within a protected area in Eastern Sicily, Southern Italy. Materials and Methods: Environmental samples (water and soil) were sourced from two streams running through the reserve and six different types of vegetation, including Platano-Salicetum pedicellatae, the Sarcopoterium spinosum community, Myrto communis-Pistacietum lentisci, Pistacio-Quercetum ilicis,Oleo-Quercetum virgilianae and a gallery forest dominated by Nerium oleander (Natura 2000 classification of habitats). Phytophthora species were recovered from samples using leaf baiting and were classified on the basis of morphological characteristics and sequencing of internal transcribed spacer (ITS) regions of ribosomal DNA (rDNA). Results: As many as 11 Phytophthora species, within five different ITS clades, were identified, including P. asparagi, P. bilorbang, P. cryptogea, P. gonapodyides, P. lacustris, P. multivora, P. nicotianae, P. oleae, P. parvispora, P. plurivora and P. syringae. No Phytophthora species were found in the Sarcopoterium spinosum comm. Phytophthora asparagi, P. lacustris and P. plurivora were the prevalent species in the other five plant communities, but only P. plurivora was present in all of them. Overall aquatic species from clade 6 (100 out of 228 isolates) were the most common; they were recovered from all five types of vegetation, streams and riparian habitats. Phytophthora populations found in the Platano-Salicetum pedicellatae and Oleo-Quercetum virgilianae show the highest diversity, while no correlation was found with the physicochemical characteristics of the soil. Conclusions: The vegetation type and the aquatic or terrestrial habitat were identified as major environmental factors correlated with the diversity of Phytophthora communities in this reserve. [ABSTRACT FROM AUTHOR]

Water erosion is the main cause of soil degradation on cultivated lands under Mediterranean climate. In these conditions, ephemeral gully erosion (EGE) is a major contributor to loss of soil productivity due to the big amounts of soil removed from the most productive top-layer. However, only a few studies on the effects of EGE and artificial controlling measures on soil degradation are available. The objective of this study was to assess the impact of EGE combined with soil infilling by tillage on several physicochemical soil properties related to soil fertility and productivity through the calculation of a soil quality index (SQI) by means of a statistical approach. It was hypothesized that the sites affected by this process of erosion and infilling of ephemeral gullies (EGs) exhibit considerable changes in the soil properties compared with locations that do not undergo this process. The study site consisted of 5 fields with contrasting soil properties which have been continuously cultivated with winter wheat. The site, located in the internal area of Sicily (Italy), represented a typical Mediterranean arable land and was severely affected by EGE. A set of soil samples were collected to investigate the spatial variation of the SQI across each location: 12 sample points in the EGE area; 4 samples in the deposition zone; 4 reference points in the area unaffected by EGE. The SQI was estimated by closely monitoring a set of main chemical and physical soil variables which influence soil fertility status: particle size (sand, silt and clay content), bulk density, gravimetric moisture, pH, electrical conductivity, carbon content (inorganic, organic and total), nitrogen content (ammonium, nitrate and total) and available phosphorus. The results showed that channelized erosion posed a threat to soil quality status even at a single cultivated field's level; therefore, the soil's ability to sustain crop production is expected to be compromised in the long run. Reductions of the SQI were observed at the EGs system area and at the deposition area in every EGs. Besides that, the lowest values of SQI were obtained inside the EGs channel and in the nearby soil areas, which were generally used to fill those channels. Soil degradation occurred in the areas which were subjected to EGE and infilling process, with key soil properties being clay (CC), sand (SaC), silt (SiC), and total organic carbon (TOC) contents. This approach helps to understand the impacts of EGE and its controlling measures on soil degradation in Mediterranean agricultural fields. [ABSTRACT FROM AUTHOR]