Washington: Researchers have figured out how a key amino acid, methionine,
vital for human nutrition, can also knock out caterpillars
threatening the citrus industry.
The Lime Swallowtail, or Citrus Swallowtail, is a well-known
agricultural pest from southern Asia discovered in the Caribbean
in 2006, and researchers say its potential impact on the US citrus
industry is cause for serious concern.
"Everything that's in the Caribbean eventually gets to Florida -
Florida is an invasive magnet," said University of Florida
lepidopterist Delano Lewis who led the study.
"That's why we're trying to make the first strike to see how to
stop it," he added, the Journal of Economic Entomology reports.
Experiments conducted at the university's McGuire Centre for
Lepidoptera and Biodiversity show that when methionine is sprayed
on leaves, it is 100 percent effective in killing larvae of the
Lime Swallowtail caterpillars within two to three days.
If not controlled, the caterpillars can completely defoliate young
wild lime plants.
Methionine is needed in the human diet for many reasons, including
protein-building and metabolism. It is environmentally safe and
harmless to citrus plants, mammals and birds, according to a
"It's a very curious phenomenon to have this nutrient amino acid
that humans can't live without, yet at the concentrations we put
on the leaves, it is toxic to crop-destructive caterpillars," said
study co-author Bruce Stevens, professor of physiology and
functional genomics in the Florida College of Medicine.