The purpose of this research was to compare the overwinter survival of populations of Heterodera glycines at different latitudes in the United States and the effect of changing latitudes before and after the initiation of dormancy. Soil samples infested with H. glycines were collected in August or October in 1992 to 1994 from soybean fields in two to four states (combinations of Arkansas, Flori...

Hirsutella rhossiliensis is a parasite of juvenile nematodes, effective against a diversity of plant-parasitic nematodes. Its global distribution on various nematode hosts and its genetic variation for several geographic regions have been reported, while the global population genetic structure and factors underlying patterns of genetic variation of H. rhossiliensis are unclear. In this study, 8...

Meloidogyne incognita, M. arenaria, M. hapla, and M. javanica were distinguishable from each other by isoelectric focusing (IEF) of nematode egg proteins. Proteins extracted from larvae and adults of Hoplolaimus columbus and from eggs of Heterodera glycines had distinctive profiles, also. Protein profiles from eggs, preparasitic larvae and egg-laying adults of M. incognita showed differences. I...

A survey of 552 soybean fields in 20 counties in Nebraska in 1986-88 revealed 35 fields infested with the soybean cyst nematode (SCN), Heterodera glycines. Identification was confirmed with a greenhouse bioassay, using 'Lee 74' soybean, and by the application of a DNA hybridization probe derived from SCN mitochondrial DNA. Most of the SCN-infested fields were located on the Missouri River flood...

The sex ratio of the Arkansas 1 isolate of Heterodera glycines was determined in experiments in which 'Lee' soybean was inoculated with either one or two larvae. A 3:1 male to female sex ratio was established for this isolate under the test conditions used. No influence of one nematode on the penetration and development to adult of another nematode in the same root was detected in double larval...

Differential sensitivity of Meloidogyne arenaria, M. hapla, M. incognita, M. javanica, and Heterodera glycines races 1 and 5 to the nonfumigant nematicides aldicarb, ethoprop, and fenamiphos was evaluated using a 48-hour root-penetration bioassay. Generally, H. glycines was more tolerant of the nematicides, especially ethoprop, than were the Meloidogyne species. Among Meloidogyne species, M. in...