Cape Town – A couple with a love for insects have been inseparable since their second year of study at Stellenbosch University.
They have now also received their doctoral degrees together during the Faculty of AgriSciences’ graduation ceremony on Tuesday.
To top it all, Vernon and Leigh Steyn both studied methods of controlling moth pests. Vernon did research on the false codling moth, while Leigh focused on the Cape grapevine leafminer.
Their love story dates back to 2011, when both were in their second year of BSc studies.
Vernon had missed a few classes and was desperate to find out what he needed to study for a scheduled test.
“After class, a girl I did not know spontaneously and kindly started helping me and provided the information I needed. And that was it,” Vernon said.
Within weeks they started dating. The pair have since completed their studies side by side and married in May 2017.
Vernon acknowledged that it is thanks to Leigh that he developed an interest in insects.
“She has the wonderful ability to notice the smallest insect in the veld, or even when we're walking in town,” he said.
After receiving their undergraduate degrees, both embarked on their MSc studies on particular agricultural pests.
Vernon studied the Mediterranean fruit fly, while Leigh focused on the Cape grapevine leafminer, which was also the subject of her subsequent doctoral studies.
Vernon, 28, and Leigh, 27, became the first of their initial first-year class to complete their doctoral studies.
Both are star students who received numerous awards for their academic achievements during their studies.
As part of his doctoral degree, Vernon looked at various biological methods that farmers can use to control false codling moth (Thaumatotibia leucotreta) in stone-fruit orchards and in vineyards.
The larvae of this moth can cause unsightly damage to fruit and is a problem when it comes to exporting.
“In the past, farmers have unsuccessfully tried to control the pest using insecticides, and because of their damaging impact on the environment and on human health, new ways of combating the moth must be found,” he said.
Vernon looked at the impact of various types of insect-specific entomo-pathogenic nematodes (worms) and fungi on the pest. He found that it is particularly effective to use nematodes during the moth’s larval stage.
“The entomopathogenic nematodes kill the larvae within 48 hours and persist within the soil for four weeks after being sprayed,” he said.
He also investigated the use of female pheromones to disorientate male moths. The method has been in use for several decades.
Vernon’s studies are, however, the first to show exactly how this effective method works.
He found that in up to 99% of cases, the male moths become so disorientated that they cannot locate females. In the process, the insect’s reproductive cycle is completely overturned.