Abstract: A method is provided for protecting a plant from nematodes and diseases associated with nematode invasion, which method comprises the step of inoculating said plant with a nematode-inhibiting strain of P. cepacia capable of colonizing said plant. The P. cepacia strain to be used should be non-pathogenic to said plant. Root inoculation of a plant with a nematode-inhibiting P. cepacia results in protection of the plant roots from nematode invasion. Foliar inoculation of the plant with these P. cepacia strains results in protection of the above-ground portions of the plant from nematode attack. Direct or indirect inoculation of seeds with nematode-inhibitory strains of P. cepacia strains can establish colonization of roots, stems and leaves of plants, and thus result in the protection of both roots and above-ground plant parts. The inoculum can be applied, for example, in the vicinity of a seed or young plant or it can be directly applied to a seed or to the above-ground parts of a young plant.

Abstract: Methods of biological control of agricultural insect pests are disclosed. These methods utilize biological control agents which are genetically altered strains of root-colonizing strains of members of the species P. cepacia. These strains are genetically altered by introduction of genes encoding insect toxic crystal proteins, and are thereby rendered insect toxic. Genetically altered insect toxic bacterial strains are also provided.

Abstract: A symbiosis plasmid from a fast-growing Rhizobium japonicum donor strain can be transferred to Rhizobium recipient strains, the recipient strains being previously incapable of forming an effective symbiotic relationship with plants of certain Glycine (e.g. soybean) varieties. The recipient strains harboring the symbiosis plasmid will form effective symbioses with soybean plants of said certain varieties, the transferred symbiosis plasmid conferring the host range or specificity of the donor strain on the recipient strains. Methods, strains, and plasmids useful for practice of this invention are also provided.

Abstract: A method of lyophilizing reagent-coated latex particles which results in a product easily reconstituted without agglutination, retains activity, and remains stable and active at storage at 4.degree. C.

Abstract: A method of lyophilizing reagent-coated latex particles which results in a product easily reconstituted without agglutination, retains activity, and remains stable and active at storage at 4.degree. C.