Summary Following square and boll loss, damaged plants may became taller and leafier than undamaged plants. Due to these changes, damaged plants may be better able to compete with their neighbours for light, water and nutrients. This explains why undamaged plants with damaged neighbours yielded about 50% less than undamaged plants with undamaged neighbours in field experiments at Narrabri. Yield reductions due to fruit loss could be greater than expected because of the negative influence of damaged plants on undamaged neighbours.