Study On The Effect Of Using Bicyclon-butyl And Pyrazosulfuron-methyl Mixed On Controlling Difficult-to-control Weeds In Rice Field

Benzobicylon is a kind of albino herbicide synthesized by Stills in Japan.Benzobicylon has strong activity to refractory weeds and sulfonylurea resistant weeds,and it can effectively control weeds that are difficult to be controlled in paddy fields.Moreover,benzobicylon has high safety to rice.But the cost is high,so it has not been widely used in paddy fields in China.Therefore,it is important to reduce the cost by reducing the use of benzobicylon.In this study,the stems and leaves of different rice varieties were sprayed with Sagittaria trifolia Linn.Scripus juncoides Roxb and Echinochloa phyllopogon(Stapf)Koss by pot method to determine the plant control effect and rice safety of benzobicylon reduction and pyrazosulfuron-ethyl on weeds in rice field,and the effect of benzobicylon and pyrazosulfuron-ethyl was analyzed by Gowing method.The main results are as follows:1.The control effect of benzobicylon and pyrazosulfuron-ethyl mixture on Sagittaria trifolia Linn.125 g a.i./hm~2benzobicylon and 30 g a.i./hm~2pyrazosulfuron-ethyl had additive effect,and the plant control effect was 78.00%at 21 d after treatment,which had no significant difference with 275 g a.i./hm~2benzobicylon.The combination of 175 g a.i./hm~2benzobicylon and 30 g a.i./hm~2pyrazosulfuron-ethyl had synergism,and the control efficacy of fresh weight was 95.04%,which was significantly higher than that of 275 g a.i./hm~2benzobicylon alone.2.The control effect of benzobicylon and pyrazosulfuron-ethyl mixture on Scripus juncoides Roxb.175 g a.i./hm~2benzobicylon and 30 g a.i./hm~2pyrazosulfuron-ethyl showed synergistic effects,the control effect of plant and fresh weight was 81.25%and 87.72%respectively 21 days after treatment,which were significantly higher than that of 275 g a.i./hm~2benzobicylon alone3.The control effect of benzobicylon and pyrazosulfuron-ethyl mixture on Echinochloa phyllopogon(Stapf)Koss.125 g a.i./hm~2benzobicylon and 30 g a.i./hm~2pyrazosulfuron-ethyl had additive effect,and the control effect was 87.72%at 21 days after treatment.The combination of 175 g a.i./hm~2benzobicylon and 30 g a.i./hm~2pyrazosulfuron-ethyl had synergism effect,and the control effect of fresh weight was 89.04%.The control effect was better than that of 275 g a.i./hm~2benzobicylon single agent.4.Safety of mixed use of benzobicylon and pyrazosulfuron-ethyl for Songjing 16.The mixed treatments have an inhibitory effect on the plant height of Songjing 16 at 15 days after treatment,and the inhibition rate is less than 5%at 45 days after treatment,and the normal growth is resumed.There are no significant effects on tiller number,effective panicle number,1000-grain weight and yield of Songjing 16.5.Safety of mixed use of benzobicylon and pyrazosulfuron-ethyl for Songjing 22.after mixed treatment with different proportions of songjing 22,the plant height of Songjing 22 was inhibited 15 days and recovered 45 days after treatment with inhibition rates less than 5%.It has no effect on tiller number of Songjing 22,but has little effect on effective panicle number,1000-grain weight and yield,and the yield loss is less than 5%.6.Safety of mixed use of benzobicylon and pyrazosulfuron-ethyl for Longjing 46.After the mixed treatment of longjing 46,the plant height was inhibited within 15 days,and recovered after 45 days,with the inhibition rates less than 6%.It had no effect on tiller number and effective panicle number,but had little effect on 1000-grain weight and yield,and the yield loss was less than 4%.7.At the dosage of 175 g a.i./hm~2and 225 g a.i./hm~2benzobicylon combined with 30 g a.i./hm~2pyrazosulfuron-ethyl could effectively control wild Sagittaria trifolia Linn.Scripus juncoides Roxb and Echinochloa phyllopogon(Stapf)Koss,respectively,and the dosage of benzobicylon was lower than the normal dosage of 275 g a.i./hm~2.The use cost of benzobicylon can be reduced appropriately...