چكيده لاتين :
family. It is the world's most expensive spice widely used in many countries. It is also increasingly used for
medicinal purposes. The most common method of weed control in this small and low growing medicinal plant is
hand weeding that needs a lot of labor costs. Chemical approach is one of the most effective methods for weed
control in saffron. Currently, some herbicide options are available to apply in saffron. For example, acceptable
broad leaved weed control would be achieved by post-emergence application of metribuzin and ioxynil when the
saffron flowers are harvested. In New Zealand, glyphosate and/or 2, 4-D I 2, 4-DB are used to clean up the beds
at early flowering's season and prior to emergence of saffron. Except some cases in Iran, selective control of
weeds by herbicides in saffron has not been widely reported. The choice of herbicide(s) depends on what are
species of weeds present. In some literatures, metribuzin showed acceptable results for weed control in saffron
fields. It is selectively used to control annual grasses and numerous broadleaved weeds. The objective of this
study was to evaluate the effectiveness of 15 herbicides with different modes of action on weeds grown in
saffron fields. Herbicides were selected based on previous studies, as well dominant weed flora in the saffron
fields where the experiment was conducted.
Materials and Methods: A field study was conducted in Agricultural and Natural Resources Research and
Education Center of Khorasan Razavi Province, Mashhad at 2014-2015 growing season. The experiment was
performed in a completely randomized block design with three replications. Treatments included metsulfuronmethyl
+ sulfosulfuron (Total®) at 32 g a.i. ha·' , su!fosulfuron (Apirus®) at 19.95 g a.i. ha·', oxadiazon
(Ronestar") at 240 g a.i. ha·', oxyflurofen (Goal®) at 480 g a.i. ha·', mesosulfuron + idosulfuron + diflufenican
(Othello®) at 96 g a.i. ha· 1, metribuzin (Sencore®) at 562.5 g ai. ha·' (applied after saffron harvest in autumn as
pre emergence of weeds), triasulfuron + dicamba (Lintur®) at 115.5 g a.i. ha·', atrazine (Gesaprim®) at 800 g
a.i. ha·', Bensulfuron methyl (Londax®) at 30 g a.i. ha· 1
, bromoxinyl + MCPA (Bromicide®) at 600 g a.i. ha·',
2,4-D + MCPA (U-46 combi fluid®) at 10!2.5 g a.i. ha· 1, nicosulfuron (Cruz®) at 60 g a.i. ha·', haloxyfop
methyl (Gallant super®) at 108 g a.i. ha· 1, bentazon (Basagran®) at 1440 g a.i. ha·1, tribenuron methyl
(Granstar®) at 15 g a.i. ha·', and weed !Tee and weed infest controls. Herbicides were sprayed at 2-3 leaves stage
of weeds (except for metribuzin which was sprayed after flower harvest in autumn and prior to emergence of
weeds) by a Matabi" rechargeable sprayer calibrated to deliver 330 lit ha·'. Four weeks after spraying, density
and dry weight of dominant weed species were measured. Flower number, flower rresh weight and dry weight of
50 stigmas were measured. Data were analyzed by SAS 9.2 software and means were grouped by Duncan
multiple range test (alpha=0.05).
Results and Discussion: The dominant weed species in the plots were Cirsium arvense (L.) Scop.,
Acroptilon repense (L.) DC. and Poa trivia/is L.. Density and dry weight of these species were significantly
decreased in herbicide treatments when measured four weeks after spraying. Significant decrease in flower
number and flower fresh weight of saffron were observed when sprayed with sulfosulfuron, nicosulfuron, 2,4-D
+ MCPA, metsulfuron-methyl + sulfosulfuron, tribenuron methyl, mesosulfuron + idosulfuron + diflufenican
and bromoxinyl + MCPA. Therefore, these herbicides cannot be used for weed control in saffron fields. Saffron
flower number and flower fresh weight did not significantly decreased when sprayed with metribuzin (79 plants
m·2 and 34.84 g m·2, respectively), oxadiazon ( 43 plants m·2 and 21.29 g m·2, respectively), bentazon (46 plants
nr2 and 23.74 g m·2, respectively), haloxyfop methyl ( 41 plants m·2 and 20.11 g nr2, respectively), oxyflurofen
(52 plants m·2 and 26.22 g m·', respectively), bensulfuron methyl (34 plants m· 2 and 16.9 g m·2, respectively),
triasulfuron + dicamba (47 plants m· 2 and 23.18 g m· 2, respectively) and atrazine (38 plants m·2 and 16.91 g m·2,
respectively). Dry weight of 50-stigmas was not signiticantly different among herbicide treatments.
Conclusions: Results showed application of metribuzin, oxadiazon, bentazon, haloxyfop methyl,
oxyfluroten, bensulfuron methyl, triasulfuron + dicamba and atrazine sound to be safe enough for saffTon and
can be recommended for weed control in saffron fields. Nonetheless, more studies need to be done in order to
evaluate undesirable long-term impacts of these herbicides on saffron corms.
