Wei ZHANG ,Jialin LIPing CAI*

1.Gold Mantis School of Architecture and Urban Environment,Suzhou University,Suzhou 215123,China;

2.Suzhou Conservation & Monitoring Center for the Classical Gardens of World Cultural Heritage,Suzhou 215001,China

Responsible editor:Ping SONG Responsible proofreader:Xiaoyan WU

Amuratae has serious hazard in Suzhou in recent years,and it is problem needs solving to simply,safely and effectively prevent and control.Chemical prevention and control is an important measure comprehensively preventing and controlling scale insect.Host of A.muratae is all woody landscape plant,which mostly grows in the city with dense population and is high.If using pesticide spray to control,it is not convenient for using pesticide,and has large environmental pollution.In the research,we selected 6 kinds of pesticides with internal absorption action,and used pesticide coating and pesticide application at the root to conduct yield prevention and control test of A.muratae,to find safe and effective prevention and control pesticide and simple and economic processing method.

Materials and Methods

Tested pesticides

10% imidacloprid wet powder(Suzhou Bianjing Plant Protection Science and Technology Co.,Ltd.),20%buprofezin methidathion wet powder(Zhejiang Tianyi Agricultural Chemical Co.,Ltd.),3% fenoxycarb (high permeability) missible oil (Zhengzhou Shalong Dawei New Pesticide Co.,Ltd.in Henan Province),40%dimethoate missible oil (Jiangsu Tenglong Biological Pharmacy Co.,Ltd.),522.5 g/L nurelle-D missible oil (U.S.Taoshi Yinong Company),0.3% matrine water aqua (Jiangyan Xingnong Bioengineering Co.,Ltd.).The above pesticides were all provided by Suzhou Plant Protection and Inspection Station.

Test time and site

Test time started from last dekad of May,2013 when nymphae hatch of A.muratae basically finished; the first pesticide application time was May 17;the second pesticide application time was June 14.Test site was in green space of Egret Park which was at the bank of Dushu Lake,Suzhou Industrial Park,and tree species was Magnolia grandiflora.

Test methods

Different pesticide application methods

Pesticide coatingTested pesticide:10%imidacloprid wet powder 10 times liquid.Pesticide coating method[1]:pesticide application part was all below 50 cm of trunk base.After coating pesticide,plastic film was used to enswathe for one week,and then untied.Trunk with DBH below 12 cm was coated 10 ml pesticide per tree; trunk with DBH above 12 cm was coated 20 ml pesticide per tree.Each treatment all repeated for three times.

Pesticide coating contained three kinds of processing methods[1].First,pesticide coating method of phloem:firstly,1/3 bark of trunk base was removed,and scraping bark parts staggered up and down to phloem until seeing white.2 half cylinder phloems with symmetric dislocation were formed,and then pesticide was coated on phloem.Second,removing tertia coating method:old tertia of trunk base was shaven along one circle until to see yellow,and pesticide was coated at the part removing teria.Third,bark direct coating method:pesticide was coated on bark of trunk base along one circle.

Pesticide effect detection:investigation on death rate was conducted after coating pesticide for 7 and 14 days,and variance analysis software was used to conduct variance analysis on corrected death rate of each treatment.Judging standard of the dead nymphae:brown,wizened body and no fresh body liquid when piercing the body.Pa=(P-P0)/(1-P0)×100%.Here,Pawas corrected death rate; P was death rate in prevention and control area;P0was death rate in control area.

Burying pesticide at the rootThe tested pesticides:10% imidacloprid wet powder and 20% buprofezin methidathion wet powder.Pesticide burying method:shallow soil layer was dug at 50 cm from trunk base,and partial root system exposed.After 20 g pesticide was sprinkled evenly,soil was covered.When using pesticide secondly,dosage increased by one times,and used amount of each kind of pesticide was 40 g/plant.

Pesticide liquid irrigating rootThe tested pesticides:10% imidacloprid wet powder and 40%dimethoate missible oil,and they were made into 100 times liquids.Irrigating root method:1 L prepared pesticide liquid was evenly irrigated at 50 cm from trunk base.When using pesticide secondly,the concentration increased to 50 times liquid,and 1 L pesticide liquid was irrigated.

Different pesticides processingThe tested pesticides:10% imidacloprid wet powder,20%buprofezin methidathion wet powder,3% fenoxycarb(high permeability) missible oil,40%dimethoate missible oil,522.5 g/L nurelle-D missible oil and 0.3% matrine water aqua.

According to test results of different pesticide using manners,removing tertia coating method had the best prevention and control effect.Powder agent was prepared into 10 and 50 times liquids,and other types of pesticides used stoste,10 times liquid and 50 times liquid.In addition,each treatment set two plants as clear water control,and was repeated for 3 times.When using pesticide secondly,dosage respectively increased by 1 times,that is,trunk with DBH below 12 cm was coated by 20 ml/plant,and trunk with DBH above 12 cm was coated by 40 ml/plant.

Results and Analysis

Yield prevention and control effects of different pesticide using manners

Prevention and control effects for five used manners of imidacloprid wet powder were shown as Table1.After 7 days,prevention and control effect of removing tertia coating method was the best,and average corrected death rate was 67.53%,which had extremely significant difference with other using manners.Corrected death rate of burying pesticide method at the root was only 23.92% and was the lowest.After 14 days,prevention and control effects of five using manners were all improved,in which corrected death rates of removing tertia coating method and burying pesticide method at the root were both above 70% and were the maxima,and they had no difference but had significant difference with other using manners.

When using pesticide secondly,using amount of imidacloprid wet powder increased by 1 times.In coating method,we only selected removing tertia coating method which had the best prevention and control effect,and using result was shown as Table2.After 7 days,corrected death rate of burying pesticide method at the root reached 100%,which had extremely significant difference with other using manners.After 14 days,both corrected death rates of removing tertia coating method and irrigating root method were above 70%.They had no significant difference,and prevention and control effect was better.

Table1 Test effects of different pesticide using manners %

Table2 Second using effects of different pesticide using manners %

Table3 Coating test results of different pesticides %

Table4 Second coating test effects of different pesticides %

Yield prevention and control effects of different pesticides

Comparison for coating effects of different pesticidesYield coating tests of different pesticides after 7 and 14 days were investigated respectively,and prevention and control results were shown as Table3.After 7 days,only corrected death rates of fenoxycarb missible oil stoste and imidacloprid wet powder 10 times liquid reached above 50%,in which processing effect of imidacloprid wet powder 10 times liquid was the best,and had significant difference with other pesticides.After diluting for 10 times,processing effect of fenoxycarb missible oil significantly declined.Prevention and control effect of matrine water aqua was the worst,which had significant difference with other pesticides.After 14 days,corrected death rate of each pesticide stoste was all above 50%.Prevention and control effect of matrine water aqua was significantly improved,and corrected death rates of stoste and 10 times liquid were both above 75%,which had no significant difference with imidacloprid wet powder 10 times liquid.The second one was buprofezin methidathion wet powder 10 times liquid,and its corrected death rate was 62.78%.

Matrine water aqua,imidacloprid wet powder and buprofezin methidathion wet powder with better prevention and control effect were used to conduct second coating test,and result was shown as Table4.Compared with once coating effect,corrected death rates of three pesticides all did not increase obviously after 7 and 14 days.Corrected death rates of matrine water aqua and imidacloprid wet powder 10 times liquid were the maxima after 14 days,and they had no significant difference.

Pesticide contrast of burying pesticide method at the rootImidacloprid wet powder and buprofezin me-thidathion wet powder were used to conduct two applications at the root on M.grandiflora,and prevention and control results were shown as Table5.Once application effect of imidacloprid wet powder was the best,and average corrected death rate after 7 days was 23.92%,and increased to 64.77% after 14 days.Application effect of buprofezin methidathion wet powder was not good,and corrected death rate after 14 days was still lower than 30%.After 7 days of second application,prevention and control effects of two kinds of pesticides were both improved significantly,in which application effect of imidacloprid wet powder was the best,and corrected death rate reached 100%,which had significant difference with buprofezin methidathion wet powder.

Table5 Test result of burying pesticide at the root %

Pesticide contrast of pesticide liquid irrigating root100 times liquids of dimethoate missible oil and imidacloprid wet powder were used to conduct two irrigating root treatments on M.grandiflora,and prevention and control effect was shown as Table6.After 14 days of once pesticide application,dimethoate missible oil had the best effect,and corrected death rate was 67.36%,which had extremely significant difference with imidacloprid wet powder.After 7 days of second pesticide application,prevention effects of two pesticides were both improved,and corrected death rate were both above 70%.After 14 days,corrected death rate of dimethoate missible oil reached 83.96% and was the highest,which had extremely significant difference with imidacloprid wet powder.

Conclusions and Discussion

Conclusions

In five application manners of imidacloprid wet powder,effect of removing tertia coating method was the fastest,and prevention effect of burying pesticide at the root was significantly improved after 14 days.The corrected death rates of the two methods were both above 70%,and they had no difference.When secondly applying pesticide,after increasing dosage,prevention effect of burying pesticide at the root was the best,and its corrected death rate after 7 days reached 100%,followed by irrigating root method,and the effect of removing tertia coating method had no significant improvement.

In yield prevention and control tests of different pesticides,prevention and control effect of coating for matrine water aqua stoste,matrine water aqua 10 times liquid and imidacloprid wet powder 10 times liquid was the best,in which effect of imidacloprid wet powder 10 times liquid was the fastest,and effect of buprofezin methidathion wet powder 10 times liquid was better.In burying pesticide method at the root,effect of imidacloprid wet powder was the best.In pesticide liquid irrigating root method,prevention effect of dimethoate missible oil was the best.

Discussion

Coating method,burying pesticide method at the root and pesticide liquid irrigating root method all had good prevention effects in yield prevention and control test.Compared with traditional spraying control,they had smaller environmental pollution and damage degree on natural enemies,and reduced pesticide consumption,which were suitable for promotion and application.Second pesticide application of burying pesticide method at the root had faster effect improvement,and corrected death rate after 7 days reached 100%.In production and practice,its operation was simple and convenient,had small harm on tree,and was suitable for pest prevention and control of tall host tree.It was suggested that dosage of 10% imidacloprid wet powder was 40-60 g/plant,and the effect was better when burying pesticide at the root during occurrence period of A.muratae nymphae.

Different pesticides selecting suitable application manner may be more conductive to playing pesticide’s effect.Yang Yi et al.used imidacloprid missible oil to prevent and control A.muratae of M.grandiflora by punching injection test,and death rates of two injection tests were both lower than 40%[2].In the research,imidacloprid wet powder was used to prevent and control by two times of burying pesticide at the root,and corrected death rate could reach 100%.Burying pesticide at the root was more suitable for playing the effect of imidacloprid.

In the test,because that prevention and control effect of once pesticide application all did not reach 90%,it needed second application to reach the requirement of prevention and control.To further decline cost and manual work,it needed further studying how to improve prevention effect of once pesticide application.

Acknowledgement

Deputy Head Sun Zhenjun of Suzhou Plant Protection Station providing test agent and help,and Municipal property Management Co.,Ltd.of Suzhou Industrial park Provided test field and support.

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