WHEAT AND BARLEY TOLERANCE AND THREE COMMON GRASSY WEED SUSCEPTIBILITY TO CLODINAFOP- PROPARGYL (TOPIK)
Mekky, M.S., E.E. Hassanein, M. R. R, Moshtohry., A. S. Kholosy
and A.M. Hassanein
Weed Research Laboratory, Field Crops Institute, ARC, Giza, Egypt
A series of experiments were carried out, in wheat fields at Sids Agricultural Research Station in three successive winter seasons 2005/2006, 2006/2007 and 2007/2008, in addition to five pot experiments in Weed Research, Laboratory FCRI, ARC, Giza in 2009/2010 winter season. The objective of the this study was to determine the tolerance of wheat and barley crops and susceptibility of three winter common grassy weeds, i.e. Avena fatua (wild oat), Phalaris minor (canary grass) and Lolium temulentum (rye grass) to clodinafop propargyl (Topik 15% WP) at rates of 70, 140 and 210 g/fad at two times of applications, 30 and 45 days after sowing (DAS) as compared to unweeded check.
The main findings revealed that wheat was tolerant to the herbicide at the recommend rate (140 g/fad ) when applied 45 DAS whereas the herbicide was very effective against canary grass and increased wheat production at Sids. On the other hand, under pot experiments, wheat was tolerant to the herbicide at the three applied rates , 70, 140 and 210 g/fad applied 30 and 45 DAS as compared with barley which was sensitive to all studied rates. Topik at 210g/fad applied 30 DAS extremely inhibited chl a, chl b and carotenoid pigments of barley plants by 56.2, 64.2 and 70.1%, respectively. Furthermore, Topik at the three rates of 30 and 45 DAS gave a 100% reduction in A.fatua and P.minor, but, at rate of 70g/fad applied at 45 DAS , a reduction of 100% in A.fatua was achieved. Moreover, Topik at 140 and 210g/fad at both 30 and 45 DAS gave approximately 100% reduction of L.temulentum. These results suggest that clodinafop-propargyl (Topik 15% WP) should be used for controlling grassy weeds effectively in wheat, but farmers should be advised to avoid using this herbicide in barley fields due to its high phytotoxicity to barley, inspite of its efficacy on controlling grassy weeds.