From tiny thrips that invade plum orchards to invasive wasps that can give a mighty sting, from diseases in grapevines, lions, leopard and apples to Nguni cattle genetics, forest ecosystems, black rhino conservation and flood management – these are the topics covered by the ten graduates of the Faculty of AgriSciences receiving their doctorates on 8 December 2016.
This week 32 degrees were also awarded to masters students of the Faculty, while 230 undergraduates (including 57 from Elsenburg) and 15 honours students also graduated.
Elleunorah Allsopp will receive her PhD in Entomology for her research towards developing a push-pull strategy to better control western flower thrips (Frankliniella occidentalis) (Pergande), in deciduous fruit orchards. These tiny insects enter plum blossoms before the petals open, and then proceed to lay their eggs in the flower parts. Allsopp showed that the insects are deterred from doing so when certain plant essential oils are applied to plum blossoms – thus providing the "push." White clover was shown to be a good prospect for planting as a trap crop next to orchards to help lure the thrips away from orchards – thus providing a "pull".
Plant pathologist Annabella Baloyi worked on a grapevine trunk disease called Petri disease, a condition that affects the productive lifespan of vineyards worldwide. Her research highlights the importance of pruning wound protection, since the fungi that cause Petri disease in South Africa release their spores during a period which coincides with the winter and spring pruning season.
For her PhD in Horticultural Science, Irene Idun found out more about the qualities that South African consumers look for when buying apples. She established that in general South Africans favour sweeter apples. Younger consumers between 18 and 25 years old had a greater preference for firmer and more sour apples. They also liked green apples better than older consumers. The results show that marketing opportunities exist for sweet tasting cultivars such as 'Fuji' that are less familiar to South African consumers in general, while consumer groups with other preferences should not be neglected.
The spread and evolution of the Feline Immunodeficiency Virus (FIV) among lions and leopards were investigated as part of Tanya Kerr's conservation ecology work. She used the presence of the virus to show how different groups of animals move around and possibly interact with each other.
Do you want to know more about the different race of the apple scab causing fungus Venturia inaequalis to be found in South African orchards? Then plant pathologist Trevor Koopman is the man to ask. After collecting samples across South Africa, he established that there's quite a variety to be found, and that some races are more virulent than others. Koopman among others found out that the types found in the Elgin region is genetically quite different from others found elsewhere in the country. He used a laboratory technique called real-time polymerase chain reaction to develop a screening test for the presence of the fungi in tissue, and to establish which fruit cultivars are resistant to it or not.
For her PhD study in Conservation Ecology, Ilse Kotzee delved into new and improved ways to manage floods. Her results can be applied by landscape managers in areas where data for process-based models and the capacity to interpret model outputs may be limited.
Sylvanus Mensah's PhD research in Forest Science was done in the mistbelt forests of Limpopo. He obtained new information about the forest ecosystem contributes to the livelihood of local communities, and how they use different aspects thereof. He also investigated the forests' carbon sequestration and honey production potential. An important finding was the significant correlation between biodiversity and the capacity of providing carbon storage. It is the first time that this aspect was taken into account for forests in South Africa.
Jeff Muntifering's PhD in Conservation Ecology provides food for thought on how tourism can help black rhino conservation in Namibia. In his thesis he applied insights he gained as a rhino researcher and community-based conservation practitioner in Namibia over the past 15 years. He says that community-based conservation and tourism strategies can serve as a good foundation to help combat rhino poaching by improving the value local people attach to conserving rhino. The study produced a clear, transferable set of prototypical elements that will help ensure sustainable expansion of rhinoceros conservation tourism ventures in Namibia and beyond.
For her PhD in Entomology, Carolien van Zyl took a much closer look at how to possibly control two invasive wasp species that are posing a potential threat to the biodiversity and agricultural sector of the Cape Floristic Region. She studied how the German wasp (Vespula germanica) and the European paper wasp (Polistes dominula) were introduced to South Africa. She also investigated the effectiveness of a range of lures and baits that could be used to monitor and control invasive wasp populations in the Western Cape.
Animal scientist Margretha Wang took a closer look at genetic diversity in South African Nguni cattle. In particular she studied the significance and distribution of so-called copy number variations. It is a type of genetic mutation that consists of deletions or duplications in the genome larger than 1kb. She developed suitable protocol with which to identify these mutations.
