History and Importance
A. euteiches was first described by Drechsler in 1925 as the causal pathogen of root rot in peas. At the time, the disease had plagued Wisconsin and the American Midwest, where monoculture was commonplace in pea production for processing, for decades. The pathogen has since been recorded in Europe, Australia, New Zealand, Japan, and throughout the United States, suggesting that the disease may have already been widespread at the time of its discovery.
Pea (Pisum sativum) is the crop where Aphanomyces causes the greatest economic damage. Aphanomyces root rot can account for yearly losses of about 10% in the fields where it occurs, and may cause losses of entire fields in conditions that are favorable to the pathogen. In agricultural regions that produce large amounts of susceptible crops and have favorable weather conditions for A. euteiches, careful monitoring is of paramount importance. Such regions include the American Midwest, particularly the Great Lakes region. In areas where peas are grown for processing, widespread Aphanomyces infection can cause processing (canning) factories to relocate, a considerable threat for local economies. In fact, prevalence of Aphanomyces root rot has ultimately shifted pea production in the United States from being predominantly in the Midwest and Eastern parts of the country to drier states such as Idaho, Washington, and Oregon where A. euteiches is still common but conditions are less favorable.
In addition to fresh peas, alfalfa is another crop where Aphanomyces root rot (ARR) causes significant economic damage. Whereas in peas A. euteiches usually occurs alone, in alfalfa it often occurs in conjunction Fusarium and Pythium spp, two other root rot-causing pathogens. Thus although A. euteiches had been known as a pathogen of pea since the 1920s, in alfalfa it was often confused with other pathogens. It was not until the 1980s that scientists from the University of Wisconsin confirmed it as a significant pathogen of alfalfa. Since then, Aphanomyces root rot has been an emerging concern in alfalfa crops in the United States and Canada, and is considered widespread in Wisconsin.
In alfalfa, A. eutiches is especially damaging in conjunction with Phytophthora medicaginis, which causes Phytophthora root rot (PRR) in alfalfa. After initial studies in Wisconsin, A. euteiches was identified as an economically significant alfalfa pathogen in other states as well. In Wisconsin, Iowa and Kentucky it often exceeds P. medicaginis in prevalence in fields where alfalfa is grown. Due to these diseases, conventional advice was to avoid growing alfalfa in any wet soils. However, with the development of ARR- and PRR-resistant varieites, wet soil conditions have become less of a concern for alfalfa production, at least as far as disease pressure is concerned. Today, modern alfalfa varieties are required to have both PRR and ARR resistance.
Read more about this topic: Aphanomyces Euteiches
Famous quotes containing the words history and, history and/or importance:
“Modern Western thought will pass into history and be incorporated in it, will have its influence and its place, just as our body will pass into the composition of grass, of sheep, of cutlets, and of men. We do not like that kind of immortality, but what is to be done about it?”
—Alexander Herzen (1812–1870)
“What would we not give for some great poem to read now, which would be in harmony with the scenery,—for if men read aright, methinks they would never read anything but poems. No history nor philosophy can supply their place.”
—Henry David Thoreau (1817–1862)
“More than ten million women march to work every morning side by side with the men. Steadily the importance of women is gaining not only in the routine tasks of industry but in executive responsibility. I include also the woman who stays at home as the guardian of the welfare of the family. She is a partner in the job and wages. Women constitute a part of our industrial achievement.”
—Herbert Hoover (1874–1964)