Fifteen small plot field tests were conducted at the Macon Ridge Branch of the Northeast Research Station near Winnsboro, LA to examine the efficacy of selected insecticide treatments against bollworm Helicoverpa zea (Boddie), and tobacco budworm, Heliothis virescens (F.). Infestation densities in the test plots were relatively high during Aug and Sep when the majority of the population was determined to be tobacco budworm. Seasonal mean fruit (square) damage was also found to be highest in the untreated plots for the field tests conducted during the late season compared with damage in the Jul tests. Laboratory bioassays with discriminating concentrations of carbamates, organophosphates and pyrethroids on tobacco budworm from this location indicated significantly higher survival compared with larvae of a susceptible laboratory strain. Several insecticide treatments significantly reduced square damage compared with the untreated plots, but in many cases excessive fruit loss still occurred. In the July and Aug tests, selected insecticide treatments applied on a timely basis resulted in significant seed cotton yield increases compared with the untreated plots. In the Sep tests applied at post-optimal timing, none of the treatments provided satisfactory control of tobacco budworm. The results of these tests show that bollworm and tobacco budworm can still be managed with recommended insecticides but not with the same degree of success experienced in the past. To reduce the probability of late season control problems, producers should emphasize production practices that will enhance early crop maturity.