Weed control in sweet lupins is still a problem. Especially the phytotoxicity of
herbicides in sweet lupins is not enough studied. Therefore a screening with 16 selected
herbicides and 4 lupin varieties has been set up. During the growing season 2005, 10 of the tested
herbicides were applied in pre-emergence, 6 in post-emergence. Pre-emergence: Most of the active matters tested in pre-emergence were not phytotoxic for lupins.
Pendimethalin (1000 g/ha),
linuron (500 g/ha),
chlorotoluron (1500 g/ha),
prosulfocarb (2400 g/ha),
clomazone (72 g/ha),
isoxaben (100 g/ha),
metamitron (1050 g/ha) and
dimethenamid-P (720 g/ha) were applied without causing any significant phytotoxic symptoms. Only the lupins treated with
aclonifen (1200 g/ha) showed a significant growth inhibition, 3 weeks
after treatment. Significantly more
chlorosis was noticed when the lupins were treated with
aclonifen or with
diflufenican, in preemergence. Post-emergence: In post-emergence,
diflufenican (50 g/ha) did not cause any crop damage.
Florasulam (5 g/ha) caused almost 100%
necrosis in L. albus as well as in L. luteus.
Bentazon (652 g/ha),
thifensulfuron-methyl (15 g/ha) and
metribuzin (175 g/ha) caused obvious
necrosis and growth inhibition of the crop. The growth inhibition was significantly more severe for lupins treated with
bentazon than if they were treated with
thifensulfuron-methyl or
metribuzin. Three weeks
after treatment,
clomazone (90 g/ha) and
diflufenican (50 g/ha), did not cause any crop injury at all. The results indicated an interesting range of active matters which can be applied in pre-emergence, but weed control in post-emergence stays difficult.