Overall, this work identifies key points to be taken into account when drawing up guidelines that govern the use of herbicide-tolerant (HT) crops in order to preserve the effectiveness of this innovation over time. This multidisciplinary expert report, based on an international literature review, assesses the effects of the cultivation of crops possessing HT traits. HT crops may appear to be useful complementary tools when farmers are facing certain difficult weed-management situations or in the context of a diversification of weed-control strategies. Their repeated use, however, can rapidly...