Texas Growers Could Benefit From Asian
Cockroaches By Alfredo Flores January 15, 2008
For cotton farmers in south Texas, a predatory flying cockroach from
Asia could turn out to be a highly beneficial insect, according to Agricultural
Research Service (ARS) scientists in
Cockroaches are generally regarded as pests, but ARS entomologist
Pfannenstiel, at the
Beneficial Insects Research Unit at Weslaco, has seen a potential benefit
from them as a natural control agent for insects that threaten U.S.
Pfannenstiel studies predatory insects that feed on eggs of
lepidopteran pests of annual crops. Lepidoptera is the insect order that
includes moths and butterflies, including the cotton bollworm and the beet
armyworm. He often spends his nights doing field tests on soybeansa crop
not often grown by farmers in Texas' Lower Rio Grande Valley. That makes soy a
good crop for research purposes, enabling Pfannenstiel to make comparisons with
cotton, the crop on which he does most of his work.
de la Fuente, Pfannenstiel starts putting out eggs of the cotton bollworm
and beet armyworm at 3 p.m. in test fields. Then they measure predation at
three-hour intervals for the next 24 hours. In the summer of 2006, they
discovered a new predator in the system: the Asian cockroach, Blattella
asahinai. Large numbersup to 100 or more per square metershowed
up in soybean fields at Weslaco.
A strong flier first seen in Florida as a troublesome household pest
in 1986, the nocturnal B. asahinai moved steadily westward, expanding
its range at night and resting during the day on leaf litter or turf.
Pfannenstiels results suggest that these roaches may become a dominant
predator of pests in soybean and cotton in the Rio Grande Valley.
In addition to the curiosity of an invasive household pest serving a
role as a biocontrol agent, the significance of this research is that it could
influence the integrated pest management of important soybean pests. The
frequency and timing of insecticide applications, for example, may be changed
in order to allow the cockroaches to reduce the pest population naturally.
more about this research in the January 2008 issue of Agricultural
ARS is the U.S. Department of
Agricultures chief scientific research agency.