Double Edged Sword
pear cacti grow in abundance in the American Southwest.
to the dry, desert regions of the Americas, the Prickly Pear
Cactus was imported by Australian ranchers in 1839 for use
as living cattle fences. Soon, the hardy, drought-resistant
cactus covered some 16 million acres of land. Impenetrable
as well as inedible by cattle, the invited guest quickly became
an unwelcome guest in the Land Down Under.
an effort to control the prickly pears, the cactus moth Cactoblastis
cactorum, was imported from Argentina in 1925. The moth
lays its eggs in the flesh of the cactus, which the young
eat and destroy as they grow. The plan worked. The transplanted
moths succeeded in ridding the outback of the prickly pear
The plan worked. The transplanted moths succeeded in
ridding the outback of the prickly pear invader.
the Californians would do after them, the Australians were
so grateful to the cactus-munching moth, they erected a commemorative
structure in its honor. The Boonargo Cactoblastis Hall pays
homage to the moth that saved rural Australia.
this story had a happy ending, a similar scenario did not
work so well in another part of the world. The cactus moth
was introduced to the island of Nevis in the West Indies in
1957, also to control pest cactus. The moth quickly spread
to surrounding islands, and arrived in the Florida Keys by
Cactoblastis Hall in Australia was built in honorof
the cactus-eating moth.
however, the moth does not merely dine on the unwanted pest
cactus; it also feeds on a native cactus called the semaphore,
pushing this rare species to the brink of extinction. Today,
any remaining semaphore cactus will only survive if covered
by a protective cage.
far, the cactus moth has spread to Georgia, and ecologists
fear it could soon establish itself in the western United
States and Mexico. There, the moth could threaten the existence
of 50 rare cactus species, some of which are an important
part of the local traditional diets and can serve as cattle
feed in times of drought.
moth larvae dine on a cactus pad.
far, no suitable means of controlling the moth has been discovered.
Pesticides as well as some forms of biological control could
have a disastrous affect on rare moths and butterflies related
to this invasive moth. The same moth that saved Australia,
could be the ruin of parts of the U.S.
- - - - - - - - - - -
pages: | 1 | 2 | 3
| 4 |
Bruce Elder, Walk
About Travel Guide; Department of Botany, Univ. of Texas