快猫短视频

A PESTICIDE that some conservationists liken to DDT鈥攁t least in its
effects on bird breeding鈥攊s being increasingly used by farmers in the US,
even though it has been denied approval for routine use.

An application to market chlorfenapyr, manufactured by American Cyanamid of
New Jersey, was denied by the Environmental Protection Agency (EPA) in April.
The agency has, however, granted 鈥渆mergency exemptions鈥� for a handful of states
over the past four years. And last month, it opened the door to wider use by
giving exemptions this year to 11 states.

The EPA鈥檚 risk assessments say that chlorfenapyr presents 鈥渟ignificant and
somewhat unusual ecological risks鈥�. In one study, mallard ducks fed diets
containing 2.5 parts per million chlorfenapyr by weight laid 41 per cent fewer
eggs and reared 56 per cent fewer normal hatchlings. The EPA鈥檚 documents say
that if chlorfenapyr were applied year after year it could build up to levels
that would threaten bird reproduction.

The pesticide is particularly effective against the beet armyworm
caterpillar, a serious pest of cotton. Environmentalists say the EPA faces
growing pressure to allow its 鈥渆mergency鈥� use on cotton fields. 鈥淚 understand
the plight of farmers,鈥� says Kelley Tucker of the American Bird Conservatory in
Washington DC. 鈥淏ut I鈥檓 not sure chlorfenapyr is the answer.鈥�

American Cyanamid rejects the comparison of its pesticide to DDT, and says
that the EPA鈥檚 feeding experiments were simplistic. The company says it has
measured residues of the pesticide in bird food items and monitored the
behaviour of bird populations to calculate the doses likely to be consumed.
Chlorfenapyr would have a 鈥渘egligible impact鈥�, the company says. Cyanamid also
notes that more than 30 countries have approved its use.

But conservationists in the US remain worried, as the area being sprayed with
chlorfenapyr seems to be growing rapidly. In 1995, for example, Mississippi got
permission to use it on up to 17 400 hectares. This year, the figure for the
state is 313 625 hectares.