Five soybean cultivars, one each from Maturity Groups (MG) III, IV, V, VI, and VII, all susceptible to Heterodera glycines, were planted in H. glycines-infested soil in April, May, June, and July at multiple locations in Arkansas and Missouri. The purpose of the study was to determine whether planting early reduces yield losses due to H. glycines. The population levels of cysts, eggs, and secon...

The most challenging obstacles to testing products for their anthelmintic activity are: (1) establishing a suitable nematode in vitro assay that can evaluate potential product use against a parasitic nematode of interest and (2) preparation of extracts that can be redissolved in solvents that are miscible in the test medium and are at concentrations well tolerated by the nematode system used fo...

Meloidogyne chitwoodi populations from Tulelake, California; Ft. Hall, Idaho; Beryl, Utah; and Prosser, Washington, significantly (P < 0.05) reduced dry shoot weights of crested wheatgrass (Agropyron cristatum L., Gaertn. and A. desertorum, Fisch. ex Link, Schult.) cultivars Hycrest, Fairway, and Nordan in experiments conducted in a greenhouse and growth chamber. Shoot growth depression, root g...

PLANT ROOTS WERE MECHANICALLY INJURED OR SUBJECTED TO NEMATODE PARASITISM TO TEST THE MODEL OF HOST DAMAGE BY TWO NEMATODE SPECIES: y = m' + (l - m')c'z(P)z(P) for y 1.0, where m' = m + (m - m) (1 - y)/[(1 - y) + (l - y)] and c' = (z(-T) + z(-T))/2. Damage functions for greenhouse-grown radish plants (cv. Cherry Belle) mechanically injured with small or large steel n...

The influence of selected soil physical and chemical factors on population density of Heterodera glycines was investigated in 1988 and 1989 in two different locations of a soybean (Glycine max) field. Soil variables of a Norfolk loamy sand were measured after planting soybeans susceptible to H. glycines. Cyst and egg populations were determined after harvest. Nematode population density was fou...

We examined the relative importance of intrinsic host factors and microparasite co-infection in generating variation in Heligmosomoides polygyrus fecundity, a parameter that serves as a proxy for infectiousness. We undertook extensive trapping of Apodemus flavicollis, the yellow-necked mouse in the woodlands of the Italian Alps and recorded eggs in utero from the dominant nematode species H. po...

The sugar-flotation-sieving (SFS) and Baermann-funnel (BF) methods were compared for nematode extraction efficiency. The SFS method recovered nematodes from more trophic groups whereas greater total numbers of individuals were recovered by BF. In a test to validate the efficiency of SFS, virtually 100% of the nematodes added to desert soil prior to extraction were recovered by four consecutive ...

The objective of this study was to evaluate sweet potato clones for resistance to root-knot nematode, Meloidogyne incognita races 1 and 3. For each nematode physiological race, a greenhouse experiment was set up in a randomized block experimental design with three replications and six plants per plot. Fifty-eight sweet potato clones from the UFVJM germplasm bank were evaluated, plus five commer...

The mermithid nematode, Filipjevimermis leipsandra, was successfully cultivated to the preadult stage in Schneider's Drosophila medium supplemented with 20% fetal bovine serum. Upon transfer to a solid substrate the preadults continued to develop into ovipositing adult females. Four molts were observed. The first molt occurred in the egg. The second occurred after 6-8 days in culture during whi...

A new cystidicolid nematode, Moravecnema segonzaci gen. et sp. n. is described from the intestine of the teleost fish Pachycara thermophilum Geistdoerfer (Zoarcidae) from the hydrothermal sites Logatchev and Snake Pit-Moose of the Mid-Atlantic Ridge, at depths of 3,008; 3,492, and 3,510 m. The new genus Moravecnema is characterised by a dorsoventrally elongated oral opening, rudimentary pseudol...