Objetivou-se neste trabalho avaliar a seletividade e a eficiência de herbicidas no controle de plantas daninhas na cultura
da alfafa. Foram desenvolvidos dois experimentos em Anápolis, GO. No primeiro, avaliaram-se oito herbicidas (imazethapyr,
MSMA, fomesafen, bentazon, chlorimuron-ethyl, imazamox) aplicados em pós-emergência da alfafa, e no segundo, seis
misturas de herbicidas [(diuron + MSMA), (diuron + MSMA), (diuron + paraquat), (diuron + paraquat)] aplicados um dia após o
corte da alfafa. Em ambos os experimentos, foram incluÃdas duas testemunhas (capinada e sem capina), sendo os tratamentos distribuÃdos
em blocos ao acaso com quatro repetições. Os herbicidas como imazethapyr, MSMA, fomesafen, bentazon, chlorimuron-
ethyl e imazamox foram seletivos à cultura da alfafa e eficientes no controle de plantas daninhas. As misturas dos herbicidas
(diuron + MSMA) e (diuron + paraquat) aplicados logo após o corte da alfafa causaram danos às folhas e aos caules remanescentes.
As brotações, todavia, surgiram isentas de toxicidade, apresentando crescimento e desenvolvimento normais. Essas
misturas promoveram eficiente controle de plantas daninhas, e não afetaram o acúmulo de biomassa seca e altura de plantas
em relação à testemunha capinada. O não-controle das plantas daninhas reduziu a produção de biomassa seca e a altura das
plantas de alfafa em 74,5% e 42,8%, respectivamente.
The objectives of this study were to evaluate the efficiency and selectivity of herbicides on the weed plants control at
the alfalfa crop. Two experiments were carried out at the Experimental Station of Agenciarural, located in Anápolis, GO. In the
first experiment it was evaluated eight herbicides (imazethapyr, MSMA, fomesafen, bentazon, chlorimuron-ethyl and imazamox)
post emergency and in the second experiment six different mixed of herbicides [(diuron + MSMA), (diuron + MSMA), (diuron +
paraquat), (diuron + paraquat)] applied one day after the alfalfa harvesting date. For both experiments were included two checks
(weedy check and no weedy check) and it was used a randomized block design, with four replications. The herbicides
imazethapyr, MSMA, fomesafen, bentazon, chlorimuron-ethyl and imazamox were selective to the alfalfa crop and efficient for
the weed plants control. The mixed of herbicides (diuron + MSMA) and (diuron + paraquat) applied after the harvesting date
were responsible for damage on leaves and stem remaining. Although the new alfalfa budding did not show any signal of toxic
and the development and growth was normal. These mix of herbicides showed an efficient weed plants control and did not affect
the harvest dry matter and plant height comparing to the weedy check. The no weedy check reduced the plant dry matter and
height in 74,5% and 42,8%, respectively.
