Method for controlling harmful organisms in genetically modified cotton plants which contain a gene derived from Bacillus thuringiensis which encodes and expresses an insecticidally active protein, which comprises applying an insecticisally effective amount of one or more compounds from the following groups and a-f, described herein, to the plants, to their seeds or propagation stock and/or to the area in which they are cultivated.The method according to the invention makes it possible to reduce the application rate of crop protection agents which act synergistically with the transgenic plants, and also to increase and widen the efficacy of the transgenic plants, and therefore offers both economical and ecological advantages.
