To the Editor:

Biological control of undesired plants is indeed a promising field of
research ("Drug War Awaits Attack of Killer Fungus," July 18).
Applications that deserve serious consideration include the removal of
noxious weeds from farms and ranches and the control of nonnative
plants that invade a fragile ecosystem.

But there are many questions that should be answered before a
virulent, persistent and broad-spectrum soil-borne disease is
introduced into any environment. The effect on nontarget species is
foremost among these.

Those who seek to release the plant pathogenic fungus fusarium to
eradicate coca in Colombia should expect as an almost certain
consequence that the coca producers would resort to application of
soil fumigants and fungicides to save their profitable crops.

Soil-borne diseases, like the many species of fusarium that attack
agricultural crops, are very difficult for farmers to control,
resulting in the use of some of the most toxic materials in the
agricultural arsenal, including methyl bromide and
chloropicrin.

Those who grow illegal crops may care little about such environmental
impacts and legal restrictions on pesticides. But this could lead to
the widespread use of persistent chemicals outlawed in the United
States or targeted for international phase-out.

This "solution" is shortsighted and potentially dangerous.

Emily Brown Rosen,
Pennington, N.J.

Note: Originally posted as a LTE