Over 5100 male tobacco budworm moths were bioassayed from May through October 1990 against 10 or 30 µg/vial doses of cypermethrin. Resistance levels were low during May and June and were similar to resistance levels recorded during 1987-1989 for these months. However, resistance levels observed during July, August and September of 1990 were higher than those recorded in previous years. Field control failures occurred in northeast Louisiana as a result of high levels of resistance to pyrethroids. Bioassays utilizing a mixed function oxidase inhibitor (piperonyl butoxide) indicated that an oxidative resistance mechanism may be present in adult tobacco budworms from Louisiana. Similar bioassays using an esterase inhibitor (butifos) suggested that an esteratic resistance mechanism may also be present in moths. In addition, over 3000 bollworm moths were bioassayed against 1, 2 or 5 µg/vial doses of cypermethrin during 1990. Those tests indicate that bollworms remain susceptible to cypermethrin and that these results are similar to monitoring data obtained during 1988 and 1989.