A male-produced aggregation pheromone, common to the rice weevil,Sitophilus oryzae, and the maize weevil,S. zeamais, was isolated and identified from hexane extracts of highly absorbent paper disks exposed individually to young virgin male weevils. A combination of preparative column and gas-liquid chromatography of disk extracts yielded purified natural pheromone. When analyzed by nuclear magnetic resonance spectroscopy and gas chromatography-mass spectrometry, the structure of the natural pheromone, "sitophilure," proved to be (R (*),S (*))-5-hydroxy-4-methyl-3-heptanone, of unknown enantiomeric composition. Synthetic racemic pheromone was highly attractive to males and females of both rice and maize weevils. In addition, both sexes of the granary weevil,S. granarius (L.) were attracted to the racemic preparation.

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An insecticidal crystal protein gene, cryIA(C), from Bacillus thuringiensis HD-1 was cloned into a broad host range vector, pSUP204, and the resulting plasmid, pSUP89A, was conjugated into a plant-colonizing bacterium, Pseudomonas cepacia 526. Southern blot analysis detected the presence of the cry gene in Pseudomonas cepacia 526 transconjugants. Production of a truncated insecticidal crystal protein in Pseudomonas cepacia was detected by Western blotting and ELISA techniques and was found to have insecticidal activity against the tobacco hornworm, Manduca sexta, in an artificial diet assay. We also followed the establishment of the Pseudomonas cepacia 526/Bt transconjugant on axenically grown tobacco plants and found that approximately 1% of the Pseudomonas cells retained pSUP89A 3 days after application. In spite of this instability, treated tobacco plants were protected from Manduca sexta infestation. Key words: Bacillus thuringiensis, Pseudomonas cepacia, insecticidal crystal protein, Cry protein.

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