Over the last two growing seasons, sampling studies have been conducted to compare the distribution and abundance of Heliothis on different cotton varieties and to test the validity of the SIRA TAC equations which express the relationship between the number of infested plant terminals and the mean number of Heliothis per plant. Results to date show t~at the current SIRATAC equations are indeed robust under current conditions and do provide an adequate estimate of insect density, calculated from the proportion of infested terminals. Differences between the number of Heliothis found on the two main cotton varieties (Siokra and Sicala) was minimal. It should be noted however, that the past few cotton growing seasons have been characterised by very low Heliothis pressure, this has meant that our analysis has been based on samples of low density populations. It has not yet been possible to evaluate the validity of the SIRA TAC relationships at high insect pressure and conclusions on varietal differences therefore remain tentative.