WORLD’S WORST PLANT PESTS
The choice is nearly impossible; that was the response from UK-based CABI when
asked by BBC News to compile a list of the worst plant pests threatening crops globally.
CABI’s chief scientist, M. Cock, pointed to a host of variable factors involved, thus
making selection an all but arbitrary exercise.
Nevertheless, CABI–a well known agri-environment research organization–made
a valiant effort that Dr. Cock labeled as being “by no means definitive therefore, nor a
serious attempt to prioritize the threats posed by different agricultural pests.” Most of
CABI’s far ranging choices follow.
Schistocerca gregaria (desert locust) was picked as the worst historical pest having been
in evidence for over 2,000 years, and with periodic capability for devastating a variety of
crops. Another candidate for historically worst pest was the image staring back from the
mirror, Homo sapiens, for introducing pest organisms to new habitats, either accidentally
or purposefully in association with some misguided venture.
In the category of hardest pest to control CABI nominated Microcyclus ulei (South
American rubber blight), a pathogen that has resisted control attempts for over a century.
Another prime offender mentioned as defying control is Fusarium xylarioides (coffee wilt
Based on the amount of pesticide once used to control it and the expense of develop-
ing transgenic strains, the label of most expensive pest to control was awarded to Dia-
brotica virgifera virgifera (western corn rootworm) even as scientists are observing first
indications that resistance to modern genetically engineered plants is breaking down.
Darkly, the pest of greatest human impact tag was attached to Phytophthora infestans
(potato blight) for several reasons, primarily its causative role in the Irish potato famine
during the mid-1800s. The fungus that devastated coffee production in SRI LANKA in
the 19th century, Hemilaea vastatrix (coffee leaf rust) also had significant human impact
being, by some accounts, a prime reason why the UK became a huge consumer of tea.
CABI pointed to Leptinotarsa decemlineata (Colorado potato beetle) as earning the
mantel of most resilient pest for developing resistance to over 50 pesticidal compounds,
noting that “this beetle therefore has effectively beaten the chemists.” The evil-doer list
also includes the class of most imminent threat handed to Puccinia graminis tritici (wheat
stem rust) strain Ug99 discovered in 1998 and now spreading across Africa, Asia, and
the Middle East.
CABI also cites some other culprits. The full listing, including supporting rational,
can be read at http://tinyurl/co42s3n. -> M. Cock, CABI, Bakeham Lane, Egham,
Surrey, TW20 9TY, UK. M.Cock@cabi.org.
–excerpted, with thanks, from BBC News, and from CABI information. [#]