Sulfuryl fluoride for management of storedproduct

Transcription

1 Sulfuryl fluoride for management of storedproduct insects Bhadriraju Subramamanyam, PhD Department of Grain Science and Industry Kansas State University Manhattan, KS Tel: Fax:

2 Comparison of heat, methyl bromide, and sulfuryl fluoride in flour mills

3 Whole facility treatments for mills Methyl bromide Heat treatment Sulfuryl fluoride

4 Experimental Setup Weather station (temperature, RH, wind, solar radiation, barometric pressure) Temp/RH logger (one point on each floor)

5 KSU Hal Ross flour mill 9626 m 3 5 floors Gas heater Propane tank High-temp. ductwork

6 Flow rate VS Pressure Pressurization Test Good seal Lower flow rate at any given pressure 3 Worse seal Flow rate (m3/s) 2 1 Better seal Pressure (Pa)

7 Airflow rate (m 3 /s) 3 2 MB1 SF1 MB2 SF Pressure difference (Pa)

8 Fumigation details Fumigation Fumigant introduction Introduced amount (kg) on mill floor Exposure Date Time period (h) First Second Third Fourth Fifth Total MB1 6 May :40 pm a SF1 27 May :00 pm MB2 11 Aug :50 pm SF2 19 Aug :45 pm MB3 11 May :00 pm b SF3 25 May :10 pm c d d a Top-up (additional gas) release at 9:50 am on 7 May b Top-up release at 8:15 am on 12 May c Top-up release at 9:45 am on 12 May d Top-up release at 7:50 am on 26 May 2010.

9 Temperature and relative humidity inside Fumigation Floor First Second Third Fourth Fifth Temperature ( C) MB ± ± ± ± ± SF ± ± ± ± ± MB ± ± ± ± ± SF ± ± ± ± ± MB ± ± ± ± ± SF ± ± ± ± ± Relative humidity (%) MB ± ± ± ± ± SF ± ± ± ± ± MB ± ± ± ± ± SF ± ± ± ± ± MB ± ± ± ± ± SF ± ± ± ± ± 0.066

10 Gas Concentration: MB1 HLT 111 hr HLT 16.4 hr HLT 10.2 hr

11 Gas Concentration: SF1 HLT 19.7 hr

12 a b HLT (h) Average wind speed (m/s) Absolute temperature difference 0.5 ( C 0.5 )

13 Effectiveness against red flour beetle life stages

14 Insect bioassays

15 Bioassay box

16 Sanitation levels simulated Poor sanitation (2 cm deep flour) Good sanitation (Dusting)

17 The whole bioassay Eggs Small Larvae Data Logger Large Larvae Pupae Adults

18 25 boxes in the mill 1 control box in lab Mill interior

19 Scatter plot showing variation in egg mortality in compartments with flour dusting as a function of the concentration x time (Ct) product during May 6-7, 2009 fumigation with sulfuryl fluoride Mortality (%) Temperature of mill floors C Ct Product (g-h/m 3 )

20 Scatter plot showing variation in egg mortality in compartments with 2 cm deep flour as a function of the concentration x time (Ct) product during May 6-7, 2009 fumigation with sulfuryl fluoride Mortality (%) Temperature of mill floors C Ct Product (g-h/m 3 )

21 Efficacy of sulfuryl fluoride against eggs and adults of Tribolium castaneum in commercial flour mills 21

22 Materials and Methods: Overall Five SF fumigations in three commercial mills Mill volumes 8,495 28,317 m floors/mill Monitored inside and outside air temperatures Monitored temperature in bioassays Monitored gas concentrations hourly One monitoring location per floor Bioassays: Tribolium castaneum Vials (25 ml; 2.6 cm diam x 4.9 cm high) Adults Eggs 22

23 Fumigation details Fumigation trial Mill Mill volume (m 3 ) 8,495 9,911 28,317 28,317 13,592 Number of floors Exposure time (h) Initial release (kg) Top-up (kg) Gas monitoring points

24 Weather monitoring Weather station (temperature, relative humidity, wind, solar radiation, barometric pressure) Temperature logger (one point on each floor) 24

25 Gas concentration monitoring Gas concentrations manually recorded every hour at 1 point on each floor 25

26 Insect bioassays 25 ml plastic vial with 5 g of wheat flour Trials 1 and 2 50 adults and 50 eggs put in separate vials One adult vial and one egg vial placed at 20 locations on each mill floor Trials adults left in a vial for 3 d to lay eggs before fumigation eggs/vial (n = 20) 15 vials placed on each mill floor Vials were kept at 28 C and 65% r.h. for 42 d for progeny production F 1 adults/vial (n = 15) 26

27 Gas concentration: Trials 1 and 2 Two adjacent mills (8495 and 9911 m 3 ) April 22-23, 2011 Old mills gas leaked quickly HLT = h Concentration (g/m 3 ) Trial 1 Trial 2 Basement Floor 1 Floor 2 Floor 3 Floor Exposure time (h) Basement Floor 1 Floor 2 Floor Exposure time (h) 27

28 Temperature: Trials 1 and 2 Maximum temp difference between floors 5 C Within each floor, air temp varied within ±1 C of average value Effect of outside temp on inside temp could not be seen Temp data of all other trials indicated the same trend 26 Trial 1 Trial 2 Temperature ( o C) Basement Floor1 Floor2 Floor3 Floor Exposure time (h) B Flr 1 Flr 2 Flr Exposure time (h) 28

29 Mortality: Trials 1 and 2 Ct 1,000 g-h/m 3 and temp 25 C 100% adult mortality; Less than 70% egg mortality Trial 1 2 Floor Ct (g-h/m 3 ) Mean temp ( C) Mortality (%) Adult Egg B B ,

30 Concentration (g/m 3 ) Gas concentration: Trials 3 and 4 Same mill at different times of year (28317 m 3 ) May and September 3-4, 2011 Trial 3 had a recirculation pump More even gas distribution only in Trial 3 For Trial 3, HLT = 47 h For Trial 4, HLT = h Trial 3 Trial Floor 1 Floor 2 Floor 3 Floor 4 Floor 5 Floor Exposure time (h) Floor 1 Floor 3 Floor 5 Floor Exposure time (h) 30

31 Mortality: Trials 3 and 4 100% adult mortality Mostly, Ct > 1,000 g-h/m 3 and temp > 30 C Egg mortality > 90% When temp was close to 25 C, egg mortality dropped to 80% even though Ct was 1,521 g-h/m 3 Trial Floor Ct (g-h/m 3 ) Mean temp ( C) Mortality (%) Adult Egg 1 1, , , , , , , ,616.9 (est) , ,283.9 (est) ,

32 Concentration (g/m 3 ) Gas concentration: Trial m 3 September 4-5, 2011 HLT = h Ct products were all slightly over 800 g-h/m 3 Temp were mostly over 30 C Egg mortality > 98% Basement Floor 1 Floor 2 Floor 3 Floor 4 Floor 5 Floor Exposure time (h) Trial 5 Floor Mean Mortality Ct temp (%) (g-h/m 3 ) ( C) Adult Egg B

33 Conclusions Maximum temp difference between floors 5 C Within each floor, air temp varied within ±1 C of average value Check temp on each floor to determine gas dosage Temp measurement at beginning of fumigation could be accurate up to ±2 C Achieved Ct products were ,630.1 g-h/m 3 Adults were all killed even at relatively low Ct and temp Confirms many other previous studies For effective kill of T. castaneum eggs, always aim for temperature > 30 C and Ct product > 1,000 g-h/m 3 33

34 Insect stage Sanitation level Treatment % Mean (SE) mortality F (df=2,7) P Adults 2 cm MB 100a < SF 100a Heat 90.1 (1.2)b dusting SF MB 100 Heat 98.7 (1.3) Pupae 2 cm MB SF 100 Heat 95.4 (2.9) dusting MB SF 98.7 (1.3) Heat 97.3 (2.7) Large larvae 2 cm MB 99.8 (0.1)a SF 100 (0.0)a Heat 96.1 (1.3)b dusting MB 99.9 (0.1) SF 100 Heat 98.2 (1.3) Small larvae 2 cm MB 100a SF 100a Heat 93.5 (2.8)b dusting MB SF 100 Heat 99.4 (0.3) Eggs 2 cm MB 99.9 (0.1) SF 92.3 (7.3) Heat 99.3 (0.3) dusting MB 99.9 (0.1) SF 88.7 (10.0) Heat 99.8 (0.1) K-State Study ( ) n = 3/trt Trt time=24 h for all

35 Cost (MB, SF, HT)-Based on treatments at K-State Month Treatment Amount used (kg or L) Total cost Cost per m 3 (based on 9628 m 3 ) May 2009 HT MB SF August 2009 HT MB SF May 2010 HT MB SF Average HT MB SF

36 Workshops and presentations May 13-15, 2009 Hands-on workshop on heat treatment Weblink: ides.htm Plus additional workshop proceedings ( ) August 19-21, 2009 & May 13-15, 2010 Hands-on workshops on sulfuryl fluoride & methyl bromide fumigations Weblink: _SF_2009/index_old.htm

37 Thank You 37