Proceedmqs of the Tth Internauonal WOIA./I/g CUll terence all Stored-product Protection - Volume 1 The use of phosphine fumigation in combination with carbon dioxide for control of mites in stored flour J ia Shengli, Zhang Zhengmmg, Yang J ie and QI J msheng! Abstract In order to approach feasible way of mites control in flour storage. a field trial of phosphme furmgation m combmation With carbon dioxide was earned out for treating flour stacks covered With polyethelene sheet m honzontal storehouse The result showed that at temperature of 19 - 28'C. alununmum phosphide (75%) 15- 2 Og/nr' plus carbon dioxide 83 - 100g/m 3 for 15 days exposure. a complete control of infected mites was obtained Introduction Cloth-bag packaged wheat flour m storage IS liable to be affected by damp and then mfested by msects and mites m humid and warm season of Chma The qualrty of stored flour will be greatly Impacted by the infection of mites Due to the fact that mites are more tolerant to phosphine than common stored gram msects, there were a lot of failures of using phosphme alone especially under poor sealmg conditions As It was known (Liang Quan , 1989). carbon dioxide has synergy to phosphme agamst msects and there were qurte a number of successful practices under the conditions of more stable. lower concentrations and extended exposure time for the control of mites Tlus paper presents a successful tnal of treatmg mite-mfected flour m Tianjm Materials and Methods There were SIX standard and special grade flour stacks ma honzontal storage for the tnal Each stack was loaded With 45 tons of flour The temperature of stacks dunng the tnal ranged from 24 - 28'C • 21- 26'C • and 19 - 26'C m upper, middle and bottom layers respectively Other conditions were given m Table 1 The volume of all stacks was 6 7m »: 3m < 3m and sealed tightly at SIX Sides With 0 Irnm thickpolyethele sheet Except for No 1-2. mites at different degrees infected all 1 Tianjm Flour Mill. 88 Sanhui Road. Tang-gu Distnct , Tianjm 300450 PR Chma stacks In order to examme precisely, mite cages contammg Tyroglyphus [aruuie , Turophaqus castellanu and Cheuleius malaccensis With 5 grams flour were laid mside the stacks at upper. middle and bottom layers respectively SIX cloth-bagged alummtum phosphide were apphed to the bottom around each stack Each bag contained 15 - 20g alumimum phosphide Table 1. The condition of stacks m the tnal No of stack Treatment AlP g/rrr' + C0 2 g/m 3 Grade of flour Weight of MOIsture flour content (ton) (%) I-I 1 5 + 100 Standard 45 138 1-2 1 5 + 100 Standard 45 134 1-3 1 5 + 100 Special 45 13 1 II-I 2+83 Standard 45 134 II-2 2+83 Standard 45 132 II-3 2+83 Standard 45 136 Pnor to the application of carbon dioxide, the stack was exhausted With air pump to about 0 01MPa and then applied carbon dioxide For the sake of avoiding moisture condensation caused by temperature difference between duct and flour. the length of duct from the cylinder to flour stack was consciously extended The concentrations of phosphme and carbon dioxide were measured at 6 positions of upper, middle and bottom layers of the stack With phosphme detectmg tubes and Orsat apparatus respectively Results and Discussion The change of phosphine concentration and obtained ct product The peak concentration and homogeneous distribution of phosphine appeared after 72 hours of application (Table 2) The relatively stable concentration of phosphine lasted nearly 480 hours, which mdicated that tlus method of apphcation conformed to the characteristic of phosphme tOXICIty to insects (Wmks and Russel, 1994) Probably It was the key factor of successful result 496
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Proceedmqs of the Tth Internauonal WOIA./I/g CUll terence all Stored-product Protection - Volume 1
The use of phosphine fumigation in combination with carbondioxide for control of mites in stored flour
Jia Shengli, Zhang Zhengmmg, Yang Jie and QI Jmsheng!
Abstract
In order to approach feasible way of mites control in flourstorage. a field trial of phosphme furmgation m combmationWith carbon dioxide was earned out for treating flour stackscovered With polyethelene sheet m honzontal storehouseThe result showed that at temperature of 19 - 28'C.alununmum phosphide (75%) 1 5 - 2 Og/nr' plus carbondioxide 83 - 100g/m3 for 15 days exposure. a completecontrol of infected mites was obtained
Introduction
Cloth-bag packaged wheat flour m storage IS liable to beaffected by damp and then mfested by msects and mites mhumid and warm season of Chma The qualrty of stored flourwill be greatly Impacted by the infection of mites Due tothe fact that mites are more tolerant to phosphine thancommon stored gram msects, there were a lot of failures ofusing phosphme alone especially under poor sealmgconditions As It was known (Liang Quan , 1989). carbondioxide has synergy to phosphme agamst msects and therewere qurte a number of successful practices under theconditions of more stable. lower concentrations andextended exposure time for the control of mites Tlus paperpresents a successful tnal of treatmg mite-mfected flour mTianjm
Materials and Methods
There were SIXstandard and special grade flour stacks m ahonzontal storage for the tnal Each stack was loaded With45 tons of flour The temperature of stacks dunng the tnalranged from 24 - 28'C • 21- 26'C • and 19 - 26'C m upper,middle and bottom layers respectively Other conditionswere given m Table 1The volume of all stacks was 6 7m »: 3m < 3m and sealed
tightly at SIX Sides With 0 Irnm thickpolyethele sheetExcept for No 1-2. mites at different degrees infected all
1 Tianjm Flour Mill. 88 Sanhui Road. Tang-gu Distnct , Tianjm300450 P R Chma
stacks In order to examme precisely, mite cages contammgTyroglyphus [aruuie , Turophaqus castellanu andCheuleius malaccensis With 5 grams flour were laid msidethe stacks at upper. middle and bottom layers respectivelySIX cloth-bagged alummtum phosphide were apphed to thebottom around each stack Each bag contained 15 - 20galumimum phosphide
Table 1. The condition of stacks m the tnal
No ofstack
TreatmentAlP g/rrr'+ C02g/m3
Grade offlour
Weight of MOIstureflour content(ton) (%)
I-I 1 5 + 100 Standard 45 138
1-2 1 5 + 100 Standard 45 134
1-3 1 5 + 100 Special 45 13 1
II-I 2+83 Standard 45 134
II-2 2+83 Standard 45 132
II-3 2+83 Standard 45 136
Pnor to the application of carbon dioxide, the stack wasexhausted With air pump to about 0 01MPa and then appliedcarbon dioxide For the sake of avoiding moisturecondensation caused by temperature difference between ductand flour. the length of duct from the cylinder to flour stackwas consciously extendedThe concentrations of phosphme and carbon dioxide were
measured at 6 positions of upper, middle and bottom layersof the stack With phosphme detectmg tubes and Orsatapparatus respectively
Results and Discussion
The change of phosphine concentration and obtainedct product
The peak concentration and homogeneous distribution ofphosphine appeared after 72 hours of application (Table 2)The relatively stable concentration of phosphine lastednearly 480 hours, which mdicated that tlus method ofapphcation conformed to the characteristic of phosphmetOXICItyto insects (Wmks and Russel, 1994) Probably Itwas the key factor of successful result
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Proceedinqs of the 7 th Iniernaiumal Workmg Conterence on Stored-product Proteciuni - Volume 1
Table 2. The change of average phosphme concentration (g/rrr') at different layers m the stacks dunng the trial
Hours after Dose of 1 5 g/ rrr' Dose of 2 g/ rrr'
application Upper Middle Bottom Upper Middle Bottom
24 o 17 o 33 o 40 o 26 o 44 o 5148 o 35 o 40 o 51 o 48 o 62 o 6872 o 65 o 58 o 60 o 65 o 69 071
168 o 45 o 50 o 50 o 55 o 61 o 69240 o 37 o 35 o 40 o 48 o 48 o 50360 o 30 o 29 o 30 o 41 o 39 o 40
480 o 16 o 12 o 18 o 24 o 23 o 28
600 o 04 o 05 o 06 o 07 o 07 o 08
The average ct product of phoshme after 600 hours ofapplication was 185 89 mg hr/L and 242 8 mg hr.L atdosage of 1 Sg/rrr' and 2g/ nr' respectively
The change of carbon dioxide concentration
Carbon dioxide concentration mamtamed higher than 4%for 168 hours m both treatments which can be evaluated thatcarbon dioxide concentration m this penod was synergetic to
phosphme (Liang Ouan, 1989)
The change of oxygen concentration
The concentration of oxygen m all stacks ranged from 18~ 19% all along the exposure time, which would be lookedupon as a mmor factor mfluencmg the efficacy of thetreatment
Table 3. The change of carbon dioxide concentration (% ) at different layers m stacks dunng the tnal
Hours after Dose of 100g/ nr' Dose of 83g/ m3
apphcation Upper Middle Bottom Upper Middle Bottom
12 4 4 6 0 8 5 4 1 5 0 8 0
24 4 8 5 6 7 0 4 3 5 1 6 3
48 5 0 5 2 5 5 4 8 5 0 5 2
72 5 0 5 1 5 0 4 7 5 0 5 0
96 5 0 5 0 5 0 4 6 4 8 4 8
120 4 7 4 8 5 0 4 2 4 4 4 5
144 4 5 4 7 4 8 4 0 4 3 4 4
168 4 3 4 6 4 6 4 0 4 1 4 2
240 3 9 4 0 4 1 3 5 3 5 3 6
360 3 2 3 6 3 5 3 0 3 1 3 2
480 3 1 3 2 3 3 3 0 3 0 3 0
600 3 0 3 1 3 2 2 8 3 0 3 0
Effectiveness of the treatment in controlling mites
No survival mites were found either on the surface of flourbags or m test cages after 240 hours exposure at dosage ofAlP 2g/m3 + C~ 83g/m3
The effectiveness of the treatment at dosage of AlP1 5g/m3 + C~ 100g/m3 was the same as above but the time
of exposure should be extended to 360 hours
No alive mite was found m all of the tested cages after 45days culture
Cost
The total cost except for labor expenses of phosphmefumigation m combmation With carbon dioxide was 1 05yuan ( RMB ) zton, but It was 2 68 yuan ( RMB ) /ton forroutme smgle phosphme furrugation
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Proceedzngs of the 7th International Work1l1gConference on Stored-product Protection - Volume 1
Conclusion
A complete control of common stored-flour mites can beachieved by usmg alumnuum phosphide 1 5 - 2 Og/rrr' mcombmation WIth carbon dioxide 83 ~ lOOg/m] attemperature from 19 - 28°C for 10 ~ 15 days of exposureThe cost of this method IS much lower than that of routmesmgle phosphme fumigation
References
Liang Quang, 1989, The current status of fumigation andcontrolled atmosphere storage technologies m Chma InB R Champ, E Highley, and H J Banks, ed ,
Proceedmgs of an mternational conference, Singapore,February 1989, 166 - 173p (In Chmese)Tan Xianchang, 1994, Evolution of phosphme fromalurmmum phosphide formulations at vanous temperaturesand humidities In E Highley, E J Wnght, H JBanks, and B R Champ, ed , Proceedmgs of the 6thInternational Workmg Conference on Stored-productProtection, Canberra, Austraha , Apnl 1994, I, 201 -203p (In Chmese)R G Wmks and G P Russell, 1994, Effectiveness of
SIROFLO®) m honzontal storages In E Highley, E JWright, H J Banks, and B R Champ, ed , Proceedmgsof the 6th International Workmg Conference on Stored-product Protection, Canberra, Australia. Apnl 1994, II,1224 ~ 1238p
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