The flatworm Bipalium
kewense is increasingly common throughout the US. Related species
are a serious problem in the London area. It is native to Malaysia
and the Orient. They likely came to this country in the soil of
imported plants. These terrestrial Planaria are predators of
earthworms. They can destroy entire earthworm populations, resulting
in great harm to the soil structure. Some of the Japanese species
are reported to kill chickens if the chickens eat them. The flatworms will
reproduce by division if they are cut or broken. The bodies are very
soft and easily damaged, resulting in multiple viable pieces. They
are about the diameter of an earthworm but can be 18" long.
They can be found in moist conditions under rocks or at times on the
surface if the soil becomes saturated. They
seem prone to damp soil conditions. They in fact encourage these
conditions by eliminating the organisms that would aerate the soil.
Thus far there are no biological remedies on the market, though many
nematodes are controlled by the entangling mycelae of fungi. It is
thought by many that the soil fungi are harmed by urea based
fertilizers. This hypothesis would match with the conditions at the
places that I have found these pests.
Bipalium kewense is
part of our high
resolution image collection
