Technical Abstract: Field trials were conducted for several years to determine the best attractant for luring adult rose chafers, Macrodactylus subspinosus (F.), to traps. During 1986, 20 compounds were evaluated in comparison to the standard (valeric acid + hexanoic acid + octyl butyrate 1:1:1) for attractancy to rose chafers. Two new standards were established in 1986: (1) Valeric acid + 1 nonanol 1:1, and (2) valeric acid + hexanoic acid + octyl butyrate + 1 nonanol 1:1:1:1. The next year, 36 compounds were evaluated in comparison to the 1986 standards. The performance of the standard binary lure was improved when the alcohol 1-nonanol was replaced with its analog trans-2-nonanol. In 1988, a test confirmed trans-2-nonanol was better than 1-nonanol in the standard lures. At the same time, a second test was conducted in which 29 new candidates were combined with valeric acid and tested against the 1986 standard valeric acid + hexanoic acid + octyl butyrate + 1 nonanol 1:1:1:1. A check and single treatment of alpha-ionone was included resulting in the discovery of a new more powerful attractant, alpha ionone. Testing of alpha-ionone continued in 1989 at which time old standards and new ones containing trans-2-nonanol were tested against the single attractant alpha-ionone and combinations containing it. Results showed improved lure performance by the addition of alpha-ionone.