Idea-caution before exploitation:the use of cybersecurity domain knowledge to educate software engineers against software vulnerabilities

The transfer of cybersecurity domain knowledge from security experts (‘Ethical Hackers’) to software engineers is discussed in terms of desirability and feasibility. Possible mechanisms for the transfer are critically examined. Software engineering methodologies do not make use of security domain knowledge in its form of vulnerability databases (e.g. CWE, CVE, Exploit DB), which are therefore not appropriate for this purpose. An approach based upon the improved use of pattern languages that encompasses security domain knowledge is proposed

The Effects of Herbivory by a Mega- and Mesoherbivore on Tree Recruitment in Sand Forest, South Africa

Herbivory by megaherbivores on woody vegetation in general is well documented; however studies focusing on the individual browsing effects of both mega- and mesoherbivore species on recruitment are scarce. We determined these effects for elephant Loxodonta africana and nyala Tragelaphus angasii in the critically endangered Sand Forest, which is restricted to east southern Africa, and is conserved mainly in small reserves with high herbivore densities. Replicated experimental treatments (400 m2) in a single forest patch were used to exclude elephant, or both elephant and nyala. In each treatment, all woody individuals were identified to species and number of stems, diameter and height were recorded. Results of changes after two years are presented. Individual tree and stem densities had increased in absence of nyala and elephant. Seedling recruitment (based on height and diameter) was inhibited by nyala, and by elephant and nyala in combination, thereby preventing recruitment into the sapling stage. Neither nyala or elephant significantly reduced sapling densities. Excluding both elephant and nyala in combination enhanced recruitment of woody species, as seedling densities increased, indicating that forest regeneration is impacted by both mega- and mesoherbivores. The Sand Forest tree community approached an inverse J-shaped curve, with the highest abundance in the smaller size classes. However, the larger characteristic tree species in particular, such as Newtonia hildebrandtii, were missing cohorts in the middle size classes. When setting management goals to conserve habitats of key importance, conservation management plans need to consider the total herbivore assemblage present and the resulting browsing effects on vegetation. Especially in Africa, where the broadest suite of megaherbivores still persists, and which is currently dealing with the ‘elephant problem’, the individual effects of different herbivore species on recruitment and dynamics of forests and woodlands are important issues which need conclusive answers

Potential insect vectors and alternative host plants of phytoplasmas in the Fynbos and Succulent Karoo biomes in South Africa

Potential insect vectors and alternative host plants of the phytoplasmas associated with grapevine yellows (GY) were surveyed in the Fynbos and Succulent Karoo biomes in the Western Cape, South Africa. Aster yellows phytoplasma (16SrI-B), which has been reported infecting grapevine in three regions in the Western Cape, was identified in a plant species belonging to the Aizoaceae. Other phytoplasmas were detected from species belonging to the Brassicaceae, Montiniaceae, Proteaceae and Zygophyllaceae and in a few insect specimens. The information will be used to confirm the insect vector status and the role of the plant species identified as alternative host plants in controlled transmission experiments

Potential insect vectors and alternative host plants of insect-transmitted liberibacter and phytoplasmas in the fynbos biome in the Western Cape

Potential insect vectors and alternative host plants of pathogens associated with citrus greening in citrus (Citrus spp., Rutaceae) and grapevine yellows (GY) in grapevine (Vitis vinifera, Vitaceae) were surveyed in the fynbos and succulent karoo biomes in the Western Cape in South Africa. The insect-transmitted diseases are associated with the presence of bacterial pathogens (\u2018Candidatus Phytoplasma\u2019 and \u2018Candidatus Liberibacter\u2019) that threaten the production and international trade of these crops. Despite previous efforts, the knowledge concerning potential insect vectors and the host range in indigenous host plants is limited. Three surveys were carried out in September (spring) in 2017, and January (summer) and August (winter) in 2018 in the natural vegetation at nine sites. Insects were collected with vacuum sampling from 20 randomly selected plant samples per species at the specific sites. Branches with leaves from the same plant species were collected, and both insects and plant samples were tested for the presence of phytoplasmas and liberibacters by quantitative polymerase chain reaction (real time PCR) or nested PCR and sequencing. Alternative host plants from 989 samples representing 42 species belonging to 19 families were analysed. None of the 42 plant species tested positive for \u2018Ca. Liberibacter africanus\u2019, the agent of citrus greening in South Africa. Aster yellows phytoplasma (16SrI-B), which has been reported infecting grapevine in three regions in the Western Cape, was identified in a plant species belonging to the Aizoaceae. Other phytoplasmas were detected from species belonging to the Brassicaceae, Montiniaceae and Proteaceae and in a few insect specimens belonging to the Auchenorrhyncha (Hemiptera). The data generated will be used for biological and epidemiological studies and the development of management strategies. This work was carried out under the framework of the European Union\u2019s Horizon 2020 research and innovation programme TROPICSAFE under grant agreement No. 727459