Maja releasing the second batch of flea beetle in Rarotonga. TIS/22091602
Native to South Africa’s tropical rainforests, one of the world’s worst invasive plants is under attack by flea beetles in Rarotonga, writes Te Ipukarea Society.
The African tulip tree,
also referred to as the “Flame of the Forest”, appears large with orange-red
flowers and yellow frilly edges. This impressive specimen was introduced into
the Cook Islands in the 1920s as an ornamental flower and has long since
planted its roots in the warm tropical climates.
Fortunately for the
African tulip tree, it has a growing interest in the outer islands and has
spread to Aitutaki, Ma’uke, Atiu, and Manihiki. However, while the African
tulip tree is considered to be the most beautiful flowering tree in the world,
it is also one of the world’s worst terrestrial invasive plants and is a major
threat throughout the Pacific region.
Efforts to reduce the
growth of the African tulip tree have been going on since 2016 when the first
biological control agent was introduced to help control the spread. The first
agent introduced to battle the spread of these large trees was the gall mite.
Research states that
gall mites are a natural solution to stunt the growth of African tulip trees.
The hope was that, because the plants are growing and spreading so rapidly, the
gall mites would be able to reduce the growth of flowers and seeds dispersing.
Unfortunately, this has
not been the case. As a result, a second biocontrol agent has recently been
released into the wild.
The second agent to
battle the “Flame of the Forest” was another small, but hopefully mighty,
insect called a flea beetle. These small, shiny-coated pests, that jump like
fleas when threatened, should solve the root cause of the African tulip tree's
Current research shows
that the flea beetle exclusively feeds on African tulip trees, which should
prevent it from munching on native species to Rarotonga.
The first batch, which
was released two to three years ago, was spread out across two locations –
Avatiu Valley and the Takitumu Conservation Area (TCA). It has not yet been
proven whether or not the first batch of beetles actually survived when they
were first released in 2021.
There is much joy with
a second consignment of a large number of over 500 beetles this time around.
Research has stated that, although the damage by the mites does not appear to
be having a significant impact, there is hope that the combined efforts of the
gall mites and the flea beetles will reduce the invasiveness of the African
The environment that the flea beetles currently reside in are very
similar to where they were sourced. They have adapted to the warm tropical
climate of the Cook Islands so they should do really well here and hopefully be
a solution to this widespread issue.
The overall hope is that ten years down the road we will look up
to the mountains and see the Flames receding. This travel bug is not an agent
that will get rid of this invasive plant in a month or a year, but maybe in
five years, if this small-but-mighty flea beetle is successful, we will see