The cotton model GOSSYM modified to simulate 2:1 skip row cotton and with a tobacco budworm, Heliothis virescens (F.), feeding routine added (WMTGOS) predicted the performance of germplasms with genetically different fruiting rates when subjected to a constant tobacco budworm infestation using the fruiting rate of 'Stoneville 213' as a standard. The fruiting rate was increased or decreased by 10% increments to a maximum of 30%. Changes were made in the horizontal fruiting interval. Using a damage routine which simulates the feeding sequence of the tobacco budworm larva, damage was applied to the simulation during the major fruiting period of the plant. Plants with increased fruiting rates were delayed less and had higher yields under tobacco budworm damage. The optimum fruiting rate based on yield was an increase of 20% whether or not simulated damage by the tobacco budworm occurred.