The life history and host range of the South American defoliator Paectes n. sp. (Lepidoptera: Euteliidae) was evaluated to determine its suitability for classical biological control of invasive Brazilian peppertree, Schinus terebinthifolia, in the U.S.A. The genus Paectes is well represented in both Florida and South America. We used DNA barcoding to assign our Paectes collections to species. However, this method did not match any known species of this genus. Larvae were collected feeding on the target weed in Brazil in June 2015 and were colonised under quarantine with mating pairs. Larval no-choice host range tests were conducted on nine members of the family Anacardiaceae, including native, ornamental, and commercial species. Larvae completed development on all species except Anacardium occidentale and Mangifera indica, although survival and development time differed significantly among species. Multiple generation testing was conducted using survivors of no-choice tests. Non-target species Schinus molle, Rhus typhina, and Cotinus coggygria produced F1 adults, although only the target weed produced F2 adults. The results of the testing suggest that although Paectes n. sp. is only capable of completing multiple generations on the target weed, Paectes larvae consume and complete at least one generation on a number of native and commercial Anacardiaceae species. Due to its relatively broad host range, and because congener species feed on the weed in the invaded range, Paectes n. sp. will not be developed as a classical biological control of Brazilian peppertree in the U.S.A.