Comparative phenology of Lepyrodiclis (Lepyrodiclis holosteoidesFenzl.) and wheat (Triticumaestivum L.) to determine the best herbicide-sensitive growth stage

To evaluate the comparative phenology of wheat and Lepyrodiclis (Lepyrodiclis holosteoidesFenzl.)growth stages and to determine the best phenological stage for some recommended post-emergence herbicide applications as well as their efficacy on Lepyrodiclis controll, this study was conducted during 2014 – 2015 in the fields of Animal Science Research Institute, Karaj. In the first experiment, comparative phenology between wheat and Lepyrodiclis was determined based on growing degree-days. Results showed that Lepyrodiclis completed its life cycle, from the seedling stage to the end of ripening, during 202 days, by achieving 2673 GDD and its developmental stages were fully adapted to the developmental stages of wheat. The second study was a split plot experiment carried out in randomized complete block design. Treatments were herbicide application time (two different wheat phenological stages; 2nd and 5th stages of Feekes scale) as main plot and application recommended doses of some broadleaved and dual purpose herbicides for wheat farms as sub plot Results showed that application of bromoxynil suppressed Lepyrodiclis effectively and reduced more than 90% of the density and biomass of the weed. Due to its decisive controlling effects, it was the best treatment between all applied herbicides. Although the use of herbicides at 5th stage of the Feekes scale increased the yield of wheat, but because of the mechanism of action of bromoxynil and according to phonological stage of Lepyrodiclis, application of bromoxynil in stage two of Feekes lead to favorable control of Lepyrodiclis in wheat fields.