Page 15 - LandscapeSAIssue111

FEATURE

An infected English Oak with traps secured over holes made by the beetles

Vergelegen risk and commercial manager Leslie Naidoo and researcher
Heather Nependa at a giant Camphor tree, fitted with repellent pouches

“This data is used to produce classified maps, after which a time-series
analysis will provide more insight into how trees respond to various
infestation levels, and how this ultimately impacts or changes tree
functioning and their ecosystem services. Monitoring these changes
over time will help inform early detection procedures,” says Nependa.

Measuring fungal growth A plastic bottle trap fitted with a chemical lure, to divert beetles from the trees
Further lab work involves experiments to measure fungal growth rates
in various nutritional mediums, which are adjusted with carbon and
nitrogen.
“These trees represent different levels of stress and will hopefully give
“Carbon and nitrogen were selected because they are readily available an indication of what kind of stress the trees are under. After the isotope
in host trees and their quantities in host trees reflect the health of the evaluation, the selected trees will be used in beetle development and
host. Carbon measures usually indicate water stress, while nitrogen fungal growth experiments.”
measures pollutants in the environment. They also affect how the
fungus – and in turn the beetles – will develop,” says Nependa. Research will continue until June 2022 and findings will be shared via
Stellenbosch University’s Department of Conservation Ecology and
Isotope analysis Entomology.
An isotope analysis experiment is also being conducted with the help
of the Stable Light Isotope Laboratory at the University of Cape Town’s “Trees provide so many benefits, from their natural beauty to helping to
archaeology department. Wood samples have been collected from two stop climate change. We are delighted that Vergelegen can play a role
beetle reproductive hosts, English Oak and London Plane trees, and in helping to find out more about this pest, so that we can protect our
two non-reproductive hosts, Wild Olive and Camphor trees. precious arboreal heritage,” says Naidoo.

Source: Progress report on PSHB research at Vergelegen Wine Estate, Heather Nependa.
Information and photos supplied by Meropa Communications on behalf of Vergelegen Wine Estate n

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