As a result of tests conducted at Seine, France, it was determined that larvae of the cinnabar moth (Tyria jacobaeae (L.)) could not complete development when reared on the following plants: Artichoke (Cinara scolymus L.), Aster sp., Cosmos sp., daisy (Leucanthemum vulgare L.), honeysuckle (Lonicera sp.), hops (Humulus lupulus L.), marigold (Calendula sp.), safflower (Carthamus tinctorius L.), strawberry (Fragaria chiloensis Duch.), Zinnia sp. On the basis of these tests and some that were conducted in England by Cameron, who published his results in 1935, it is concluded that the cinnabar moth can safely be introduced into the United States for control of the weed, tansy ragwort (Senecio jacobaea L.).