Paper Information

Title:  A REVIEW ON RESEARCHES CONDUCTED ON PADDY FIELD WEEDS AND HERBICIDES IN IRAN (FLOUR CHANGE, BIOASSAY OF HERBICIDE DEGRADATION AND DWARFISM IN RICE)
Type: PAPER
Author(s): YAGHOUBI B.,ALIZADEH H.,RAHIMIAN H.,BAGHESTANI M.A.,SHARIFI M.M.,DAVATGAR N.
 
 
 
Name of Seminar: IRANIAN WEED SCIENCE CONGRESS
Type of Seminar:  CONGRESS
Sponsor:  ANKOMANE OLOME ALAFHAYE HARZE IRAN
Date:  2010Volume 3
 
 
Abstract: 

STUDY ON THE PADDY FIELD WEEDS IN IRAN BEGAN IN 1960S. IN EARLIEST STUDIES ONLY THREE WEED SPECIES WERE MENTIONED TO INTERFERE IN RICE FIELDS. TEN YEARS LATER 15 WEEDS WERE REPORTED CAUSING YIELD LOSS IN PADDY FIELDS. THE PAST DECADE STUDIES SHOW THAT THE DIVERSITY AND NUMBER OF WEEDS HAVE INCREASED AND ARE AROUND 30 WEED SPECIES. AMONG THEM PERENNIAL SEDGES AND BROADLEAVED SPECIES HAVE BUILD UP DRAMATICALLY. IN RECENT STUDIES “MONOCHORIA VAGINALIS” (CHRACH) AND “ECHINOCHLOA ORYZICOLA” (INTELLIGENT BARNYARD GRASS) WERE REPORTED AS NEW INVASIVE SPECIES IN IRANIAN RICE FIELD WEED FLORA. ALSO SELECTIVE HERBICIDES OF RICE HAVE BEEN INTRODUCED ALONG WITH WEED FLORA STUDY. IN PAST FOUR DECADES 14 HERBICIDES INCLUDING GRASS KILLER, BROAD LEAF KILLER AND THREE PURPOSES HERBICIDES FOR CHEMICAL CONTROL OF PADDY WEEDS HAVE BEEN REGISTERED. FEW YEARS AFTER HERBICIDES INTRODUCTION, THEY HAVE BEEN USED EXTENSIVELY AND NOW AROUND 99 PERCENT OF FARMERS USE AT LEAST ONE HERBICIDE. EVEN THOUGH REGISTERED HERBICIDES INCLUDE A VARIETY OF CHEMICAL GROUPS AND MECHANISM OF ACTION, BUT 90 PERCENT OF AVAILABLE HERBICIDES IN THE MARKET ARE CONFINED TO 3-4 HERBICIDES. CONTINUAL APPLICATION OF SOME HERBICIDES ACCOMPANIED BY FERTILIZERS, SOIL EROSION AND COMPACTION BECAUSE OF MACHINERY MOVEMENT ALL TOGETHER HAVE BEEN CONTRIBUTING IN FLOUR CHANGES AND BUILDING UP THE POPULATION OF PERENNIAL SEDGES AND BROADLEAVED WEEDS. THE VERY RECENT RESEARCH SHOWS THAT CONSECUTIVE APPLICATION OF THIOBENCARB HERBICIDE OR APPLICATION OF THIS HERBICIDE BEFORE TRANSPLANTING CAUSES MORPHOLOGICAL AND PHYSIOLOGICAL DISORDERS IN RICE CROP GROWTH. THIOBENCARB CAUSES RICE SEEDLINGS TO REMAIN SHORT IN STATURE THAT IS CALLED “RICE DWARFISM”. BIOASSAY OF HERBICIDES SHOWS THAT DWARFISM OF RICE SEEDLING IS BECAUSE OF DEGRADATION OF THIOBENCARB TO MORE TOXIC COMPOUNDS BY MICROORGANISMS. MIXING OF ANOTHER RICE SELECTIVE HERBICIDES E.G. OXADIARGYL AND BUTACHLOR WITH THIOBENCARB DECREASED THIOBENCARB PHYTOTOXICITY SHARPLY.

 
Keyword(s): 
 
Yearly Visit 23  
 
Latest on Blog
Enter SID Blog