Status in Nebraska:
The
Russian wheat aphid was discovered in Nebraska in the fall of 1986 in volunteer
wheat and winter barley in Kimball and Banner counties. By July 1987, all
Panhandle and several southwest counties of Nebraska had confirmed infestations.
Infestations in the fall of 1987 and in the spring of 1988 generally were
light, although severe aphid infestations occurred in localized areas in
the Panhandle where the aphids overwintered. In other areas the aphid was
present in the fall but did not survive the winter.
The RWA is expected to be a continuing threat to Nebraska wheat and
barley production. The extent of the problem each year will vary greatly
and will depend on several factors.
Origin and Time of Introduction:
As it name implies it was first discovered in Russia. It was first
spotted in North America in 1980 in central Mexico. It made its United
States debut in 1986 in Muleshoe, Texas. That summer, damaging infestations
were observed in wheat and barley fields in New Mexico, Kansas, Oklahoma
and Colorado.
Common Characteristics:
It is a small insect of gray greenish color, has winged forms (?) no
males have been spotted in the US. Because of the no males factor the insects
can reproduce parthenogenically, and because of this its success is highly
dependant on over wintering sites.
Environmental Impact:
Damage occurs from the aphid feeding on the sap of wheat or barley
which can lower plant yield and also spread viruses and diseases from one
plant to another.
Management:
Control is limited at this time as this is a relatively new pest to
the area. One method is to remove volunteer wheat 3 weeks before planting.
Avoiding early planting in winter wheat is advised, as is weed reduction,
proper fertilization and choice of a good seed. Because the plant material
has a habit of rolling around the insect (leaf rolling) pesticides are
not usually advised.
