In order to have successful control against any pest the key is to know the target.
Fleabane comes in many forms but the most common plaguing the Australian grain growing regions is Flaxleaf fleabane (Conyza bonariensis). Flaxleaf fleabane has traditionally been kept at a manageable level through cultivation, however with industry push to move to minimum tillage systems has led to fleabane emerging as a major problem.
Fleabane germinate generally in autumn or spring, starting as a 2 tip pointed cotyledon growing erect before starting to branch. Generally mature plants are around 1 metre in height with a hairy stem, flowers are white-yellow and present spring through to autumn.
Most of the viable seeds germinate from the surface, about half from 0.5 cm, about a tenth from 1 cm and none from 2 cm at 18/25 degrees C over 32 days. Nearly all viable seed (~95%) emerged within the first 10 days with the rest taking up to 20 days. 50% emergence occurs 4-5 days after moisture is supplied at 20 degrees. 1% seed on the soil surface is viable after 3years and 10% seed that is buried 5-10 cm deep is viable after 3 years (S. Walker, GRDC, 2009). Fleabane plants are prolific seed producers producing up to 110’000 seeds per plant, seeds are not rapidly spread by wind.
For ultimate control, attacking fleabane at every stage of the cycle is necessary however not always practical in cropping situations. Fleabane is most susceptible to herbicide application when it is soft, green and actively growing. There are several herbicide options for control fleabane but as always they all have to be right to fit in the farming system as the majority of registered herbicide options do have residual activity and in some case lengthy plant backs.
A robust and cost effective option, Imtrade Paratrooper, is registered for control of fleabane, has no residual activity and no lengthy plant backs. Trial work has been extensively conducted as part of the registration process is well documented in link below;
further reading is available through;