This report describes the identification of a new toxigenic strain of Bacillus thuringiensis specific for long-horned beetles. B. thuringiensis Bt866 encodes a cry3Aa-like gene (Bt886cry3Aa) that is 1,956 bp in length and is predicted to encode an 85.78-kDa protein. The gene is highly similar to cry3Aa1, differing in only six nucleotides and four amino acids. The four disparate amino acids occur within the conserved domains of the Cry3Aa toxin. The expression of Bt866cry3A in Escherichia coli cells resulted in a high level of toxicity toward Apriona germari Hope larvae. More than 75% of the larvae were killed; and the remaining survivors exhibited slower growth. These results indicate that the toxigenic strain Bt886cry3Aa encodes a protein that is specific against long-horned beetles. Genetic engineering of the Bt866cry3Aa gene into poplar plantations may provide resistance to long-horned beetles.