Author
 |
Hesler, Louis |
|
LANGHAM, MARIE - SOUTH DAKOTA STATE UNIV |
|
Submitted to: APSnet Resource Center
Publication Type: Popular Publication Publication Acceptance Date: 4/29/2004 Publication Date: 5/7/2004 Citation: Hesler, L.S., Langham, M.A. 2004. Riding on the wind - part i: cereal aphids and viral diseases of cereals. APSnet Resource Center. www.apsnet.org/education/k-12plantpathways/newsviews Interpretive Summary: The purpose of this article is to review the factors involved in annual re-establishment of cereal aphids and resultant levels of yellow dwarf diseases in cereal crops in the northern Great Plains. Cereal aphids can damage wheat and other small grains by their feeding, and they are also vectors of two major viral pathogens of cereals, barley yellow dwarf virus and cereal yellow dwarf virus. Dispersal of these pathogens is dependent upon dispersal of their aphid vectors. In the northern Great Plains, cereal aphids are present every year but limited in their ability to survive harsh winters. Each spring, re-establishment of aphids in the northern Plains depends largely upon two factors: 1) large populations of aphids on cereal crops in the southern Plains, and 2) weather conditions that favor occurrence of low-level jet winds to transport aphids from the southern to the northern Plains. Jet winds can disperse cereal aphids several hundred miles to where the aphids fall out over a localized area, ranging from a few counties to portions of several states. In other years, aphid population build-ups don't coincide with low-level jet winds, but aphids are still carried northward each spring by lighter, less sustained southerly winds, and aphid transport is much slower and less dramatic. Lighter aphid infestations and lower incidence of virus in cereal fields are associated with these conditions, but still may impact cereal crop production. Technical Abstract: The purpose of this article is to review the factors involved in annual re-establishment of cereal aphids and resultant levels of yellow dwarf diseases in cereal crops in the northern Great Plains. Cereal aphids can damage wheat and other small grains by their feeding, and they are also vectors of two major viral pathogens of cereals, barley yellow dwarf virus and cereal yellow dwarf virus. Dispersal of these pathogens is dependent upon dispersal of their aphid vectors. In the northern Great Plains, cereal aphids are present every year but limited in their ability to survive harsh winters. Each spring, re-establishment of aphids in the northern Plains depends largely upon two factors: 1) large populations of aphids on cereal crops in the southern Plains, and 2) weather conditions that favor occurrence of low-level jet winds to transport aphids from the southern to the northern Plains. Jet winds can disperse cereal aphids several hundred miles to where the aphids fall out over a localized area, ranging from a few counties to portions of several states. In other years, aphid population build-ups don't coincide with low-level jet winds, but aphids are still carried northward each spring by lighter, less sustained southerly winds, and aphid transport is much slower and less dramatic. Lighter aphid infestations and lower incidence of virus in cereal fields are associated with these conditions, but still may impact cereal crop production. |
