Dealing with spear thistle

Tokozwayo Sive, a production scientist who specialises in pasture science at Animal Production Improvement Research and Development at the Eastern Cape Department of Rural Development and Agrarian Reform, suggests ways to control an invasion of spear thistle.

- Tokozwayo Sive

Spear thistle is a member of the Asteraceae family and is commonly known as roadside thistle, bull thistle and plume thistle.

The plant is native to Europe, Western Asia and North Africa, but is now naturalised and widespread throughout South Africa.

It is believed that spear thistle was introduced into South Africa for the first time during the Boer War (in the 1880s), probably with hay or fodder. It was first identified near Van Reenen in KwaZulu-Natal. The plant is prevalent in areas with cooler temperatures and high rainfall, but it is rare in the drier areas of South Africa.

A spear thistle invasion is a significant threat to both agricultural and natural ecosystems: the plant is a competitor with grasses that are beneficial to livestock, disrupting natural community dynamics and causing injuries to animals.

LEGISLATION

According to the Conservation of Agricultural Resources Act of 1983, spear thistle has been classified as an invader species under Category 1, and it is imperative to remove and destroy it immediately. The plant is uneconomical and has traits that make it harmful to animals. In addition, the uncontrolled spread of this herbaceous biennial is constantly threatening the livelihoods of farmers as it progressively reduces grazing capacity and croplands and causes animal injuries.

The plant thrives on abandoned lands and disturbed soils, and competes with grasses for soil resources and sunlight.

HABITAT OF THE SPEAR THISTLE

Spear thistle can adapt and grow in various soil types under different moisture conditions.