Research On Pesticide Reduction Technology For The Prevention And Control Of Root Rot And Weeds In Wheat Fields In Heilongjiang

With the rapid development of modern agriculture,the problems involved in the production process such as pesticide over usage and low utilization rate of pesticides have become increasingly prominent.Reducing the number of pesticides,environmental pollution,and pesticide residues,and improving the utilization rate of pesticides are the keys to the current pest control work.Northeast China is an important planting area for spring wheat.Wheat root rot and wheat weeds seriously affect the growth of wheat,resulting in serious yield losses.To maintain the production of spring wheat in Northeast China in the future,assure food security,and reduce pesticide usage,this study was conducted to control wheat root rot and broadleaf weeds by adding adjuvants and improving spraying methods.The results are as follows:1.To clarify the control efficiency of spring wheat root rot regarding the reduction of the seed treatment agent,6% Pyrazole · Thiram(wettable powder)was selected as the seed treatment agent.By reducing the seed treatment agent dosage,and adding the adjuvants,the results showed that with 30% reduction of 6% Pyrazole · Thiram,mixed with different adjuvants,the wheat root rot can be controlled effectively.The efficacy of the reduced treatment was not significantly different from that of the conventional treatment.The incidence and disease index of root rot were strikingly lower than those of the control without seed treatment agents.The results of the safety and yield test indicated that adding adjuvant in the seed treatment agent has no significant effect on the growth of the wheat;however,it provided some positive yield effects.With a 30% reduction of 6% Pyrazole · Thiram mixed with “Jijian”,the theoretical yield reached 4252.2 kg/hm2,which was 23.10% higher than that of the regular dosage.2.The results of field trials of the reduced herbicide “Dicamba” mixed with adjuvants using the conventional spraying method to control broadleaf weeds in wheat fields showed that the reduction of 30% mixed with the adjuvant “Qigong” could effectively control weeds in wheat fields.The control efficacy at 15 days after the treatment were 91.61% respectively,and the control efficacy and fresh weight control effect were 93.63% and 93.20% respectively at 30 days.The efficacy of the reduced treatment was not significantly different from that of the conventional treatment.The theoretical yield of 30% reduction mixed with “Qigong” treatment was 3612 kg/hm2,which was 1.34% higher than that of the conventional method.3.The results of field trials of the herbicide “Dicamba” in reduced dosage on the control of weeds in wheat fields using the electrostatic spraying method showed that the control effect of each reduction treatment after 15 days was significantly lower than that of the conventional method.However,after 30 days,the control and fresh weight effect of the 30% dosage reduction using the electrostatic spraying method were 94.41% and 93.68%,respectively,which was not significantly different from that of the conventional method.The theoretical yield of a 30% reduction of the herbicide “Dicamba” in the electrostatic spraying treatment was 3654 kg/hm2,which was 3.04% higher than that of the conventional method.4.The results of field trials of the herbicide “Dicamba” in reduced dosage mixed adjuvants using the electrostatic spraying method to control weeds in wheat fields showed that the effect of the 50% dosage reduction mixed with“Qigong” after 15 days and 30 days,were 91.90% and 93.63%,respectively,which was not significantly different from that of the conventional method.5.The droplet deposition effect of mixed adjuvants for the conventional spraying and electrostatic spraying methods were measured and calculated using the random block method and the effective utilization rate of pesticide mixtures under different spraying methods was determined.Using the conventional spraying method without adjuvants as a baseline,the droplet spreading diameter,density,and the effective utilization rate were found to be 187.59 ?m,211.37 deposits/cm2,and 24.32%,respectively.Under the conventional spraying method with adjuvants,the droplet spreading diameter,density,and the effective utilization rate were found to be 265.39 ?m,128.16 deposits/cm2,and 30.27%,respectively.Under the electrostatic spraying method with the adjuvant “Qigong”,the droplet spreading diameter,density,and the effective utilization rate were found to be 18.85 ?m,160.84 deposits/cm2,and 41.08%,respectively.The results showed that the droplet spreading diameter under the electrostatic spraying method decreased significantly compared to that of the conventional spraying method and the droplet density increased;The droplet spreading diameter after using adjuvants increased significantly and the droplet density decreased.The effective utilization rate of pesticides treated by electrostatic spray with adjuvants is significantly higher than that of the conventional spraying method with and without adjuvants,and the electrostatic spraying method without adjuvants.The electrostatic spray mixed with the adjuvant “Qigong” achieved the highest deposition volume(0.76 mg/cm2),and the effective utilization rate of the pesticide reached 41.08%.To conclude,a 30% reduction of 6% Pyrazole · Thiram,mixed with “Jijian” adjuvant can be used to prevent wheat root rot,a 30% reduction of “Dicamba” mixed with “Qigong” and electrostatic spraying with a dosage reduction of 30% could be used to control weeds in wheat fields.Adjuvants enhance the droplet size distribution,while electrostatic spray increases the droplet density,electrostatic spray mixed with adjuvants can maximize pesticide utilization and control weeds in the field,the additional adjuvants while using the electrostatic spraying method can be used to achieve a better weed control effect when the dosage is reduced by 50%.