|Golden A Morgan|
|Inglis Debra A|
|Santo Gerald S|
|Baldwin James G|
Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/30/1994
Publication Date: N/A
Citation: N/A Interpretive Summary: Nematodes are microscopic worms that attack plant roots and cause seven billion dollars worth of agricultural losses each year in the United States. This brief report describes the discovery in the state of Washington of one type of nematode (called the pea cyst nematode) that attacks pea plants. The report is the product of collaboration of ARS, university, and Washington State Department of Agriculture personnel. First, scientists in Washington discovered fields with large areas of pea plants turning yellow and producing only a few peas; the scientists also observed nematodes on the roots. ARS scientists at Beltsville then identified the nematode as the pea cyst nematode, Heterodera goettingiana. In the U.S., the pea cyst nematode was twice isolated many years ago from agricultural fields, but attempts to re-isolate the nematode failed. Therefore, this discovery of the pea cyst nematode in Washington is very important, because it is the only significant establishment of the nematode in pea fields in the U.S. Because the nematode has caused major economic damage to pea in Europe, the results will be of interest not only to scientists studying nematodes but also to appropriate action agencies. Indeed, appropriate APHIS and state regulatory agencies were informed in August and September 1993, immediately after identification of this pest had been confirmed by ARS scientists at Beltsville.
Technical Abstract: A cyst nematode was discovered on pea roots in western Washington and was identified as the pea cyst nematode, Heterodera goettingiana Liebscher, based on morphology of cysts and second-stage juveniles and host range. Infested areas in fields appeared as well-defined, circular or irregular spots that often turned a brilliant yellow before harvest time. Severely affected plants from an area in an infested field with approximately 2 cysts/g soil were pale green and stunted, had poorly developed roots, lacked Rhizobium nodules, and produced few pods and seeds. Light-colored cysts were obvious on plant roots before flowering, but as the cysts matured and darkened, their ease of detachment impeded visual observation. Invasion, discoloration, and rotting of roots by secondary organisms further complicated late-season detection. The pea cyst nematode has a limited host range, is widespread throughout Europe and the Mediterranean Basin, and also occurs in Japan. Although in the United States H. goettingiana has been reported in Illinois in a greenhouse and in a single field each in Pennsylvania and Idaho, this species has never become established in commercial pea fields in the U.S. The distribution of this nematode in pea fields throughout North America needs to be determined.