A partially purified preparation as well as two formulations of exotoxin from Bacillus thuringiens& (thuringiensin) were evaluated for nematicidal activity. The methods used in our evaluations included direct contact nematicidal assays, hatching tests, infection tests in seed pouches using the cucumber/ root-knot nematode (Meloidogyne incognita) system, and greenhouse test using the root-knot nematode. While contact nematicidal activity was not observed against juveniles of M. incognita, 100% mortality occurred when the free-living nematode, Caenorhabdit& elegans, was used as the test organism. Nematode infection evaluations in the seed pouch assay showed reduced root galling at relatively high concentrations (>10 mg kg i). Greenhouse assays indicated significant reduction in the soil population. However, the degree of control in relation to the amount of material applied, as measured by the gall numbers, larvae from soil/roots, and plant growth parameters, was not considered adequate. Data on the plant response in relation to treatment with different formulations of the toxin are presented.

Seven adhesive-producing nematode-trapping fungi were tested for their ability to capture nine different nematodes. The nematodes included species that are free living as well as plant and insect parasites. The fungi displayed no selectivity. Each fungus was able to trap and consume all of the different nematodes tested. A study of cuticle surface saccharides of five of the nematodes revealed the presence on all the nematodes of glucose–mannose and N-acetylgalactosamine residues. L-Fucose residues were not found on any of the nematodes. The involvement of lectins in the capture of prey by nematode-trapping fungi is discussed.

An N-acetylgalactosamine-specific protein was purified from mycelial homogenates of the nematodetrapping fungus Arthrobotrys oligospora by using affinity chromatography. The molecular weight of the protein was estimated at 22,000 by its comparative mobility on sodium dodecyl sulfate-polyacrylamide slab gels. Pretreatment of nematodes with the purified protein reduced entrapment, indicating a role for the sugar-binding protein in recognition and capture of prey by the fungus.