Sonchus Oleraceus

Sonchus oleraceus or also called as Sowthistle originates from Europe (Munz, 1968). During the 1800s Europeans were travelling the world and carrying their crops, so they brought the Sowthistle to Australia. Sonchus oleraceus is biennial or an annual weed. It is glabrous, milky (white latex in all plant parts), and erect stems with can get between 20 to 150 cm tall. Hollow, septate at the nodes and relatively pentagonal in section because the decurrent midribs in the leaves (Alex et al., 1980). As a pioneer species, it invades disturbed sites worldwide and it is a common weed on cultivated lands as germination can occur at any time of the year, achenes bear papus promoting wind dissemination and the mating system is selfing. Sonchus has no vegetative reproduction and the seeds can stay in the seed bank for up to 30 months (Lewin, 19478;
For the reason that Sowthistle develop and flower rapidly and produce copious wind and bird spread seeds that germinate fast in significant numbers, it is very important to manage Sowthistle in a crop production farm, to avoid the quickly spread and the possible herbicide
Simazine resistance was reported for first time in 1968 in a biotype of Senecio vulgaris (Ryan, 1970). Since then there have been numerous reports of weed biotypes exhibiting resistance to PS II-inhibiting herbicides (Heap, 2003). Until now, only two mechanisms of resistance to triazines have been identified. With few exceptions, resistance to triazines is due to a modification at the target site, the D1 protein of the PS II complex, which has most often been attributed to a simple gene psbA mutation (Bettini et al., 1987; McNally et al., 1987; Gasquez, 1991; Smeda et al., 1993; Darmency, 1994; Alfonso et al., 1996; Jordan, 1996; Kelly et al., 1999; Schwenger-Erger et al., 1999; Stankiewicz et al.,