This study reports on field trials using Magnet formulation with insecticide to determine the effect of applying the attracticide to a centrally located BollgardII (Bt) cotton crop on levels of Helicoverpa spp.

When comparing BollgardII with conventional cotton, the lower water requirement and higher lint yield of Bollgard II was explained by greater insect damage in conventional cotton.

BollgardII accumulated yield faster than conventional cotton due to higher retention combined with a very low proportion of tipped plants.

The Australian cotton industry has now had three seasons of commercial scale use of Bollgard II, the two Bt gene product developed by Monsanto for insertion into cotton for control of Heliothis.

The use of carbon isotopes as a 'natural marker' of Helicoverpa has proven very useful in this regard (see below).