A facultative fungal parasite, Arkansas Fungus 18 (ARF18), was isolated from at least 10 different sources of Heterodera glycines in different areas in the United States. Techniques used for isolation and in vitro evaluation of fungal parasites of H. glycines were described. Successful isolation of probable egg parasites depends on isolation from individual eggs. Selective isolation and a simpl...

Two soybean breeding lines (D82-2397A and J82-190) resistant to Heterodera glycines race 5 produced higher yields (P = 0.05) than the race 4-resistant cultivar Bedford for 2 years when planted in a field infested with H. glycines race 5 at Tiptonville, Tennessee. Yields were not different between D82-2397A and Bedford when planted in fields infested with race 3, race 9, or with no cyst nematode...

The influence of selected plant species on egg hatch and subsequent development of Heterodera glycines race 3 was investigated. Plants tested included four soybean cultivars, red clover, alfalfa, hairy vetch, field corn, sweet corn, cabbage, tobacco, cotton, and wheat. Soybean stimulated egg hatching more than any of the other plant species, with H. glycines-resistant cultivars being more stimu...

A commercial seed treatment containing Pseudomonas cepacia was applied to Glycine max cv. Williams 82 (susceptible to Heterodera glycines) and was compared to Fayette soybean (resistant to H. glycines) for control of H. glycines at two locations in Illinois. The soil at the first location was sandy in texture and the field was irrigated, whereas the soil at the second location was a silty clay ...

Effects of a mixture of the postemergence herbicides acifluorfen and bentazon, and simulated defoliation expected from green cloverworm on population densities of Heterodera glycines were determined in field plots in Iowa. The herbicide mixture and defoliation each suppressed soybean growth. Population densities of H. glycines were generally lower in herbicide-treated than untreated plots. Popu...

Soybean cultivars from maturity groups III-V were grown in Heterodera glycines-infested locations in northeastern and southeastern Kansas from 1991 through 1994. Yield performance and nematode reproduction were significantly (P <0.01) affected by host response to H. glycines and year, whereas effects of cultivars within host response categories and cultivar x year interactions were generally ne...

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...

Calonectria crotalariae enhanced root penetration of Lee 74 (susceptible) and Centennial (resistant) soybeans by juveniles of race 3 of Heterodera glycines. Numbers of cysts in and on the roots of Lee 74 increased during the first 30 days in the presence of the fungus. Percentage of root infection by the fungus increased at 40 days in Lee 74 in the presence of the nematode. Numbers of cysts in ...

We developed a quick and reliable technique to distinguish live and immobile (presumed dead) Heterodera glycines second-stage juveniles (J2) following their treatment with microbial culture filtrates. About 50 J2 in 1 ml of culture filtrate or water were placed in wells of a 24-well tissue-culture plate. After incubation, the nematodes in the wells were observed with the aid of an inverted micr...