Evaluation of the possibility of herbicides use with adjuvants to control broadleaf weeds in saffron (Crocus sativus L.)

A field study with 3 replications based on RCBD was conducted in order to improve the efficacy of some herbicides using adjuvants in the control of broadleaf weeds of saffron. Oxadiazone, oxyfluorfen, rimsulfuron and dicamba+ tritosulfuron herbicides at recommended rates of 500, 700, 10 and 150 a.i. ha-1, respectively without adjuvants and in reduced rates 375, 480, 8.75 and 112, respectively were used when they were tank-mixed with and without citogate (0.2% v.v-1) and humix 99 (0.25% v.v-1) as well as a control plot with no herbicide application and hand weeding. Weed species of Polygonum aviculare and Cardaria draba with relative density of 26% and 20.5%, respectively were the dominant weeds in the experimental field. The results showed that hand weeding significantly increased the yield of saffron flower and corm. Application of oxyflurfen and oxadiazone in reduced rates decreased saffron damage while addition of citogate to these herbicides increased the phytotoxicity damage in saffron. Addition of humix to these herbicides had no effect on phytotoxicity damage. Although application of rimsulfuron and dicamba+ tritosulfuron in reduced rates reduced phytotoxicity damage and increased yield of saffron, these herbicides have the potential to damage saffron even at reduced rates. Adding citogate to these herbicides can increase the efficacy of these herbicides in weeds control but considering the potential of these herbicides in damage to saffron, application of these herbicides in saffron fields is not recommended even at reduced doses. Application of oxyflurfen at 480 a.i. ha-1 without adjuvant and tank-mixed with humix were best treatments for use in saffron fields. However, it is also possible to use oxadiazone at 375 a.i. ha-1 to control saffron broadleaf weeds.