Understanding the genetics of sex determination in insects and its relevance to genetic pest management.

Sex determination pathways regulate male and female-specific development and differentiation and offer potential targets for genetic pest management methods. Insect sex determination pathways are comprised of primary signals, relay genes and terminal genes. Primary signals of coleopteran, dipteran, hymenopteran and lepidopteran species are highly diverse and regulate the sex-specific splicing of relay genes based on the primary signal dosage, amino acid composition or the interaction with paternally inherited genes.

Development of a molecular genetics and cell biology toolbox for the filamentous fungus Diplodia sapinea.

Diplodia sapinea (Fr.) Fuckel is a widespread fungal pathogen affecting conifers worldwide. Infections can lead to severe symptoms, such as shoot blight, canker, tree death, or blue stain in harvested wood, especially in Pinus species.

Genomic characterization of novel viruses associated with Olea europaea L. in South Africa.

South Africa has a small but growing olive industry. Until now, no virological research has been carried out on this crop locally. Seventeen samples were collected from various olive cultivars from a single producer in the Stellenbosch growing area of South Africa.

species associated with in South Africa, including two novel species.

Ambrosia beetles (Coleoptera: Curculionidae: Scolytinae) are small wood-boring insects that live in an obligate symbiosis with fungi, which serve as their primary food source. Beetles residing in the genus have evolved a unique association with a clade of that falls within the aptly named Ambrosia Clade (AFC). The discovery of the invasive polyphagous shot hole borer, , in South Africa, has heightened awareness of ambrosia beetles and their symbionts in the country.

New and Interesting Fungi. 7.

Two new genera, 17 new species, two epitypes, and six interesting new host and / or geographical records are introduced in this study. New genera include: (based on ) and (based on ). New species include: (from hypersaline sea water, Qatar), (from mycangia of , USA), (on leaves of , Brazil), (from pre-stored , South Africa), (from soil, South Africa), (from dead capsule of , Germany), (from house dust, Canada), (from soil, South Africa), (on ascomata of ascomycete on twigs of , South Africa), (on leaf litter, Spain), (on larva, Thailand), (from soil, South Africa), (from pasture mulch, South Africa), (from soil, South Africa), (on stem, bark of living tree of sp.

partially overlap on asymptomatic and symptomatic tissues of in agroecosystems and conservation areas in northern South Africa.

Members of the are well-known endophytes and stress-related pathogens. We recently characterised the diversity of in healthy tissues of three tree species in the , namely , and . Here we ask how that diversity compares with the diversity associated with dieback on those tree species.

Molecular networking and computational NMR analyses uncover six polyketide-terpene hybrids from termite-associated Xylaria isolates.

Fungi constitute the Earth's second most diverse kingdom, however only a small percentage of these have been thoroughly examined and categorized for their secondary metabolites, which still limits our understanding of the ecological chemical and pharmacological potential of fungi. In this study, we explored members of the co-evolved termite-associated fungal genus Xylaria and identified a family of highly oxygenated polyketide-terpene hybrid natural products using an MS/MS molecular networking-based dereplication approach. Overall, we isolated six no yet reported xylasporin derivatives, of which xylasporin A (1) features a rare cyclic-carbonate moiety.

Mechanical Egg Activation and Rearing of First Instar Larvae of (Hymenoptera: Siricidae).

Egg activation is a cellular transition of an arrested mature oocyte into a developing embryo through a coordinated series of events. Previous studies in Hymenoptera have indicated that mechanical pressure can induce egg activation. In this study, we developed the first egg activation protocol for the haplodiploid insect pest, (Hymenoptera: Siricidae), from two climatically different regions in South Africa to demonstrate the broad applicability of the method.

sp. nov and sp. are core gut microbiome symbionts of the two-spotted stink bug.

Stink bug species ( superfamily) have developed an interdependence with obligate bacterial gut symbionts in specialized midgut crypts (M4 sub-region). Species of the family (predominantly ) are vertically transferred to their offspring and provide nutrients that cannot be obtained from plant sap food sources. However, the bacteria in the other gut compartments of stink bugs have rarely been investigated.

Natural infection of white grubs (Coleoptera: Scarabaeidae) with entomopathogenic nematodes in the KwaZulu-Natal province of South Africa.

White grubs are root feeding larvae of beetles (Coleoptera: Scarabaeidae) that are sporadic pests in agriculture and can lead to economic damage. The grubs feed on the roots of plants, while the adult beetle can bore into underground stems, as well as cause defoliation of plants. Sporadic incidence of larvae with symptoms of nematode infections were detected in wattle and sugarcane plantations in the KwaZulu-Natal province of South Africa.

Efficacy of Commercially Available Entomopathogenic Agents against the Polyphagous Shot Hole Borer in South Africa.

The invasive ambrosia beetle, , was first reported in South Africa in 2018. The beetle has now spread to eight provinces of the country and has had a devastating impact on both native and non-native tree species. This is especially true for trees located in urban and peri-urban environments.

Genomic characterization of a novel potyvirus infecting Barleria repens in South Africa.

The complete RNA genome sequence of a novel member of the genus Potyvirus infecting Barleria repens has been determined. A plant showing symptoms of virus-like leaf mosaic was sampled in the Western Cape province of South Africa, and the associated virus has been tentatively named "Barleria repens mottle virus" (BaRMoV). The genome of BaRMoV consists of 9,561 nucleotides and encodes a typical potyvirus polyprotein that is 3,105 amino acids long.

Characterisation of the Alarm Pheromone of Bathycoelia Distincta (Pentatomidae).

Bathycoelia distincta (Pentatomidae) is the dominant pest in South African macadamia orchards, where adults are responsible for causing severe yield losses. Similar to other hemipterans, B. distincta release volatile compounds from scent glands that can deter natural enemies and act as an alarm signal among conspecifics.

Diversity and Molecular Barcoding of Stink Bugs (Hemiptera: Pentatomidae) Associated with Macadamia in South Africa.

Stink bugs are major pests of macadamia in South Africa. Accurate identification and knowledge of species composition are important to inform management practices. The overall aims of this study were to identify stink bug species from macadamia orchards in South Africa using morphology, and to establish a DNA database based on the gene region.

Genomic characterization of soybean blotchy mosaic virus, a cytorhabdovirus from South Africa.

Samples showing blotchy mottle symptoms were collected from soybeans in North-West province, South Africa. The assembly of high-throughput sequencing data from three samples yielded contigs of 13,426 to 13,435nt, which represent the first complete genome sequences of soybean blotchy mosaic virus (SbBMV). SbBMV shows a typical cytorhabdovirus gene organization (3'-N-P-P3-M-G-L-5'), with each putative gene product being most similar, but with only 49.

Genetic diversity of the two-spotted stink bug Bathycoelia distincta (Pentatomidae) associated with macadamia orchards in South Africa.

The South African macadamia industry is severely affected by a complex of stink bugs, dominated by the two-spotted stink bug, Bathycoelia distincta Distant (Pentatomidae). This species was first discovered during the spring of 1984 in the Limpopo province. Although considerable effort has been spent trying to manage this pest, it continues to be a pest of concern for the macadamia industry.

Fungal Communities of Leaves Are Influenced by the Insect Pest .

Fungal communities in above-ground tree tissues are hyperdiverse and are influenced by biotic interactions with other organisms living in or on these tissues. These biotic interactions are, however, still poorly understood. In this study, we aimed to understand how insect-associated gall formation on foliage correlates with the diversity of foliar fungal communities in surrounding healthy leaf tissue, as well as the co-occurrence patterns among the members of the fungal community.

Remnants of horizontal transfers of Wolbachia genes in a Wolbachia-free woodwasp.

Background: Wolbachia is a bacterial endosymbiont of many arthropod and nematode species. Due to its capacity to alter host biology, Wolbachia plays an important role in arthropod and nematode ecology and evolution. Sirex noctilio is a woodwasp causing economic loss in pine plantations of the Southern Hemisphere.

Genome-wide association study identifies SNP markers and putative candidate genes for terpene traits important for Leptocybe invasa resistance in Eucalyptus grandis.

Terpenes are an important group of plant specialized metabolites influencing, amongst other functions, defence mechanisms against pests. We used a genome-wide association study to identify single nucleotide polymorphism (SNP) markers and putative candidate genes for terpene traits. We tested 15,387 informative SNP markers derived from genotyping 416 Eucalyptus grandis individuals for association with 3 terpene traits, 1,8-cineole, γ-terpinene, and p-cymene.

A Detection Assay to Identify Alternative Food Sources of the Two-Spotted Stink Bug, Bathycoelia distincta (Hemiptera: Pentatomidae).

The two-spotted stink bug, Bathycoelia distincta Distant (Hemiptera: Pentatomidae), is a serious pest in South African macadamia orchards. This pest is predominantly controlled using insecticides, thus alternative control methods are essential. The stink bugs arrive as adults in the orchards, during the early nut set season, but little is known about their alternative plant hosts before their arrival.

The evolution of insect visual opsin genes with specific consideration of the influence of ocelli and life history traits.

Background: Visual opsins are expressed in the compound eyes and ocelli of insects and enable light detection. Three distinct phylogenetic groups of visual opsins are found in insects, named long (LW), short (SW) and ultraviolet (UV) wavelength sensitive opsins. Recently, the LW group was found to be duplicated into the LW2b and the LW2a opsins.

Loss and Gain of Gut Bacterial Phylotype Symbionts in Afrotropical Stingless Bee Species (Apidae: Meliponinae).

Stingless bees (Apidae: Meliponini) are the most diverse group of corbiculate bees and are important managed and wild pollinators distributed in the tropical and subtropical regions of the globe. However, little is known about their associated beneficial microbes that play major roles in host nutrition, detoxification, growth, activation of immune responses, and protection against pathogens in their sister groups, honeybees and bumble bees. Here, we provide an initial characterization of the gut bacterial microbiota of eight stingless bee species from sub-Saharan Africa using 16S rRNA amplicon sequencing.

Toward a Natural Classification of : A Study of the Type Specimens of .

The genus includes more than 200 epithets, but only the type species, and a dozen or more other species have been identified based on DNA sequence data. The taxonomic status of the other species remains unconfirmed because they lack either morphological information or DNA sequence data. In this study, types or authentic specimens of 16 "" species are reassessed to clarify their identity and phylogenetic position.

The relevance of studying insect-nematode interactions for human disease.

Vertebrate-parasitic nematodes cause debilitating, chronic infections in millions of people worldwide. The burden of these so-called 'neglected tropical diseases' is often carried by poorer socioeconomic communities in part because research on parasitic nematodes and their vertebrate hosts is challenging and costly. However, complex biological and pathological processes can be modeled in simpler organisms.

Botryosphaeriaceae on Syzygium cordatum across a latitudinal gradient in South Africa.

The Botryosphaeriaceae is a family of endophytic fungi, many of which are latent pathogens of woody plants. Although extensively sampled in some parts of the world, little is known regarding their occurrence across different environmental conditions. This study considered the presence of the Botryosphaeriaceae on Syzygium cordatum trees across a latitudinal gradient.