Lesion nematodes (Pratylenchus spp.) are abundant in soybean fields in Illinois and Indiana (2, 3) and are capable of causing damage to soybeans (1, 5). Use of nematicides to protect soybeans is not economical. Breeding res is tan t varieties may be a more logical approach, but a technique which might prove adequate for fast and effective screening of s o y b e a n lines has not been available....

The influence of Pratylenchus penetrans on the incidence and severity of Verticillium wilt was examined in the potato cultivars 'Kennebec', 'Katahdin', and 'Abnaki'. Single-stem plants were grown in soil maintained at a temperature of 22 +/- 1 C. Axenically cultured nematodes were suspended in water and introduced to the soil, at a rate of ca 5,000/25.4-cm pot, through holes made around each st...

A survey was conducted to determine the assemblage and abundance of plant-parasitic nematodes and their associations with soil factors in organically farmed fields in Minnesota. A total of 31 soil samples were collected from southeast (SE), 26 samples from southwest (SW), 28 from west-central (WC), and 23 from northwest (NW) Minnesota. The assemblage and abundance of plant-parasitic nematodes v...

Nematode occurrence at specific locations throughout a water catchment-irrigation system was determined. Soil samples were collected from five water source locations on the slopes of Olomana Mountain and Maunawili Valley and from about 40 plant species on 18 farms (56 ha of 480 ha irrigated by the reservoir). Water was sampled from the catchment reservoir at 0.3 m, 9 m, and 18 m (bottom). A far...

Isolates of Pasteuria penetrans were evaluated for ecological characteristics that are important in determining their potential as biological control agents. Isolate P-20 survived without loss of its ability to attach to its host nematode in dry, moist, and wet soil and in soil wetted and dried repeatedly for 6 weeks. Some spores moved 6.4 cm (the maximum distance tested) downward in soil withi...

The most commonly encountered plant-parasitic nematodes in eastern Washington Vitis vinifera vineyards are Meloidogyne hapla, Mesocriconema xenoplax, Pratylenchus spp., Xiphinema americanum, and Paratylenchus sp.; however, little is known about their distribution in the soil profile. The vertical and horizontal spatial distribution of plant-parasitic nematodes was determined in two Washington V...

The interaction between Pratylenchus neglectus (Pn) and Meloidogyne chitwoodi (Mc) was investigated at soil temperatures of 15, 20, and 25 C on barley and potato. Maximum numbers of Pn and Mc penetrated barley roots at 20 C, whereas a minimum number penetrated at 15 C. Pratylenchus neglectus restricted root penetration by Mc over time and vice-versa. Population densities of each species increas...

The abundance of Pratylenchus scribneri in soil and root habitats was compared in potato and corn plots during 1986-88. Nematodes were extracted from 100-cm(3) soil samples and the roots contained within the samples. The percentage of the population recovered from soil, similar among years and crops, averaged ca. 50% at the beginning and end of the growing season and ca. 20% from early to late ...