Common Sowthistle (also known as Milkthistle), is widespread across northern grain-growing regions of Australia. Common Sowthistle is one of the most difficult to control weeds in winter crops with a significant proportion of populations resistant to Group B herbicides. The weed was once considered to be winter-dominant; however, it is now found all year round. Sowthistle seed has virtually no dormancy. Germination can therefore commence as soon as seeds settle on moist soil and thereby reinfesting.
Dr Peter Boutsalis, Plant Science Consulting, Adelaide, SA, investigated the bioefficiency of four glyphosate formulations including Roundup ULTRAMAX in controlling susceptible and glyphosate-resistant Sowthistle Biotypes
For more information read our Resistant Sowthistle (Milkthistle) Info Note