Weed management systems in cotton are continually evolving, particularly in response to reduced cultivation and chipping and increased use of herbicides. The use of permanent beds and reduced tillage is likely to cause a shift in the problem weed spectrum, towards perennial weeds and those with rhizomatous root systems, which have previously been controlled with cultivation. A survey of 23 properties found that most weeds were much worse on fully cultivated fields than permanent bed fields. The exceptions were rhyncho, datura, nutgrass and polymeria, which were much worse on permanent bed fields. These data support the use of permanent beds as a way of reducing over-all weed pressure, but emphasise the need to .develop control strategies targeted at perennial and rhizomatous weeds.