story to find out more.
A Faster Way
to Tell Look-alike Leafminer Flies Apart
By Luis Pons
July 30, 2002
Agricultural Research Service scientists
have developed a new high-tech method for telling apart two species of
leafminer insects, one of which has caused extensive crop damage around the
world but is not known to be in the United States.
The test developed by ARS molecular biologist Sonja Scheffer combines two
procedures--called polymerase chain reaction (PCR) and restriction fragment
length polymorphism (RFLP)--to differentiate between Liriomyza
huidobrensis and L. langei, two species of leafmining flies so
similar that scientists, until recently, believed they comprised one species.
Telling apart species of leafminers and other insects is greatly important
to people such as quarantine officers, pest-management experts and researchers
who work together to keep potentially damaging insects from entering the United
Leafminers affect many vegetable and flower crops, including peas, beans,
melons, onions, tomatoes, potatoes, celery, garlic, lettuce, chrysanthemums and
carnations. Their larvae tunnel inside leaves and other plant parts as they
feed, leaving winding trails visible though the leaf surface. During outbreaks,
they can cause substantial economic losses.
Scheffer's new PCR-RFLP analysis can be used with adult, larval or pupal
specimens of leafminers. The test can be performed by anyone with access to a
laboratory and the proper equipment. The entire procedure can be done in one
day, compared to several days and additional expenses involved in another
testing method called DNA sequencing.
Before developing the new detection method, Scheffer and biological sciences
technician Matthew Lewis, based at the ARS
Entomology Laboratory in Beltsville, Md., used DNA sequence data from
leafminer genes to show that the two leafminer species existed. DNA data also
showed that the invasive leafminers causing extensive crop damage around the
world are L. huidobrensis, not L. langei. Currently, L.
huidobrensis is not known to be present in the United States.
Read more about this finding in the
issue of Agricultural Research magazine.
ARS is the U.S. Department of
Agriculture's chief scientific research agency.