In the cotton growing region of the lower coastal plain of South Carolina, there are two distinct flights of Heliothis spp.The early flight (June) consists primarily of U. virescens (>90%) and the late flight (mid-July and August) is primarily H. zea (>95%). Early season control of H. virescens usually requires 1-2 insecticide applications; if these could be eliminated, it would allow growers to reduce production costs and take greater advantage of beneficial insects. South Carolina is now in the boll weevil eradication zone which will eliminate early season applications for this pest and allow an even greater buildup of beneficial species.

In 1989, date indicated cotton that was left untreated in June yielded as good as those plots treated full season; 1044 lbs. lint/AC compared to 1017 lbs. in cotton treated full season with a pyrethroid. The untreated check yielded 553 lbs. lint. Mid-season untreated had 550 lbs. lint. In a second test, full season treatment yielded 1154 lbs. lint compared to 1143 lbs. in plots not treated early for H. virescens.

In four studies in 1990, there were no significant differences in three locations comparing full season vs. no early season treatment. Yields were much lower due to dry growing conditions (430-500 lbs. lint/AC). The average over 4 locations was 454 lbs. lint in full season plots compared to 428 lbs. in early season untreated. During both years, maturity differences were not detected between treatments.

These results indicate that early season control of H. virescens may not be necessary in cotton grown in the lower coastal plain of SC in absence of the boll weevil.