Identification of an A2 population of Phythophthora andina attacking tree tomato in Peru indicates a risk of sexual reproduction in this pathosystem

Tree tomato, Solanum betaceum, is an Andean fruit crop previously shown to be attacked by Phytophthora andina in Ecuador and Colombia. Blight‐like symptoms were discovered on tree tomato plants in the central highlands of Peru in 2003 and shown to be caused by P. andina. Isolates of P. andina, collected from three different plantations in Peru over a 6‐year time span (2003–2008), were compared genetically with P. andina isolates from Colombia and Ecuador to test whether the pathogen population is geographically structured in the Andes. Restriction fragment length polymorphism (RFLP), mitochondrial DNA and simple sequence repeat (SSR) genetic markers, and mating type behaviour indicated that the Peruvian P. andina population from tree tomato is genetically distinct from populations infecting tree tomato in Colombia (CO‐1) and Ecuador (EC‐3, Ia, A1), but is more similar to the population infecting solanaceous hosts of the Anarrhichomenum complex (EC‐2, Ic, A2). Such geographic substructuring within this pathogen species could result from spatial isolation. Most strikingly, in contrast to the Ecuadorian and Colombian P. andina isolates from tree tomato, the Peruvian isolates have the A2 mating type. The presence of both mating types in the Andean population of P. andina attacking tree tomato indicates a risk of sexual reproduction and the presence of long‐lasting oospores in this pathosystem.     

Characterization of Colletotrichum truncatum from papaya,pepper and physic nut based on phylogeny,morphology and pathogenicity

Colletotrichum truncatum (syn. C. capsici) has been identified as the causal agent of anthracnose on various hosts, predominantly pepper (Capsicum spp.) plants. The aim of this study was to determine whether C. truncatum isolates infecting papaya, pepper and physic nut in southeastern Mexico are morphologically, genetically and pathogenically different, in order to improve disease management strategies. A total of 113 C. truncatum isolates collected from five producer states were subjected to phenotypic characterization and divided into six different morphological groups. These morphological traits and the location of the isolates were used to select a subset of 20 isolates for further studies. Differences in the pathogenicity of the isolates were tested with a cross‐inoculation assay using pepper, papaya and physic nut. The pathogenicity tests revealed that all isolates could infect the three hosts and produce typical anthracnose symptoms, indicating a lack of host specificity for this species and therefore its pathogenic potential on other plants. Phylogenetic analysis using internal transcribed spacer (ITS) and glyceraldehyde 3‐phosphate dehydrogenase (GAPDH) sequences of the C.   truncatum isolates from this study and reference strains was performed, grouping the isolates into a monophyletic clade. This study reports for the first time the characterization of C. truncatum causing anthracnose disease on three different hosts in Mexico.     

Physiological and physical measures to control postharvest diseases of fruit

Preharvest and postharvest decay of persimmon fruits caused byAltemaria alternata can be effectively alleviated by a growth hormone effect on the physiology of the fruit An orchard application of gibberellin (GA₃), prior to harvest, maintains the calyx in an upright, erect position, thus preventing the formation of a microclimate beneath the calyx, which is conducive to decay development in this region. The additional effect of delaying fruit maturation, leads to an increased resistance of the fruit to postharvest decay development on the entire fruit surface during storage. Other measures, of a physical nature, which can be employed to control postharvest disease, include a change in environment, such as achieved by controlled atmosphere storage or modified atmosphere packaging. The dominant control factors appear to be the naturally produced CO₂ and possibly acetaldehyde.     

Are There Arid Land Soilscapes in Southwestern Europe?

No studies have proven the existence of soil assemblages typical of arid lands in Europe. This study was carried out in a representative territory of the southeastern part of the Iberian Peninsula, Almería province, which is the driest part of Europe, to determine if soils characteristic of arid lands are present. In order to analyse the spatial distribution of soils, the authors made use of mathematical tools previously developed in biodiversity and pedodiversity analysis, such as richness, entropy indices, abundance distribution models, diversity‐area relationships and nested subset analysis. The study demonstrates that the soil types or pedotaxa are typical of mountainous arid lands. Shallow and weakly developed soils (e.g. Leptosols, Regosols and Arenosols), Calcisols, Gypsisols and Solonchaks, cover most of the study area, and pedodiversity analysis demonstrates that the pedotaxa spatial patterns follow the same regularities as in other areas, environments and scales. In view of the fact that the class of landscapes identified in this study is unique in Europe, the Tarbernas desert and other arid lands sites of the study area merit preservation as part of the European geological, geomorphological and pedological heritage. Copyright © 2015 John Wiley & Sons, Ltd.     

Landscape changes as visible indicators in the social,economic and political process of soil erosion: A case study of the municipality of puebla de valles (Guadalajara Province), Spain

This paper proposes a methodological approach to data gathering as a sound basis for understanding land degradation processes, breaking down barriers of distrust between Government officials and land users, and promoting participation in planning for soil and water conservation. It examines how landscape changes, of value as indicators of erosion, are perceived by land users and can be used in planning. It is proposed that the participation of land users in the construction of questionnaires, data gathering, analysis and writing up of the findings are examples of the participatory initial stages in planning.