1. Missouri Fumigation Training January 10 – 11, 2010
We have…..
Alternatives….
Carol Jones, PhD, PE, Oklahoma State University Stored Products Research and Education Center
Missouri Fumigation Training January 10 – 11, 2010

2. Missouri Fumigation Training January 10 – 11, 2010
We have…Alternatives
Reasons for alternative methods for controlling insects…maintaining grain quality
Insect resistance
Customer request (organics, social, marketing)
Environmental concerns
Safety
Governmental regs
Missouri Fumigation Training January 10 – 11, 2010

3. Missouri Fumigation Training January 10 – 11, 2010
We have…Alternatives
Methods…
Aeration
Ozone
Heat Treatment
Ethylene….”Apple Gas”
Missouri Fumigation Training January 10 – 11, 2010

4. What does aeration do? Little insect reproduction occurs below 60F
Eggs are controlled at 40F
40F is tough to do in some areas
So fumigation is still required but can be reduced
Carol Jones, PhD.
Stored Product Engineering
Biosystems and Ag. Engr. Dept.

5. Missouri Fumigation Training January 10 – 11, 2010
We have…Alternatives
Little insect reproduction occurs below 60F
Eggs are controlled at 40F
40F is tough to do in some areas
So fumigation is still required but can be reduced
Missouri Fumigation Training January 10 – 11, 2010

6. You have…Alternatives
Missouri Fumigation Training January 10 – 11, 2010

7. Electrical Generation of Ozone
Attractive alternative
Eliminates some of the concerns
No residues because degradation product is oxygen
No transportation of product
No storage issues

8. Objectives
Determine the effectiveness of ozone fumigation on six stored product pests in a grain mass of wheat under field conditions during the month of October, the traditional time during storage when grain is fumigated in Oklahoma

9. Experimental Protocol
Conducted in October 2007
Steel grain bins contained 13.6 metric tons of hard red winter wheat
One bin treated; one bin control
Grain was poor quality because of extreme wet conditions at end of growing season

10. Ozone Generator OZAT Model CFS-3A Operated at 30 g/hr
Produced three targeted ozone concentrations of 25, 50, and 70 ppm within the bin

11. Ozone Introduced into Bin
Through a 6.4 mm tube from generator just upstream of fan into a 10.2 cm pipe connected to the aeration fan transition into the bottom of the bin
Axial fan moved 0.21 cubic meters/sec of air/ozone through grain mass
Ozone concentration decreased as it moved through the grain mass

12. Insect Sampling Tubes
Tubes of 10.2 cm diameter were inserted into bins at depths corresponding to targeted ozone levels
Ozone rose through the tubes to come in contact with bags containing insects
A recirculation system was used to recover ozone exiting the top of the grain mass and then injected back into the bottom of the bin through a closed loop system
Ozone concentrations monitored every 8 hrs

13. Insects Evaluated Rhyzopertha dominica Lesser Grain Borer
Sitophilus oryzae
Rice Weevil
Tribolium castaneum
Red Flour Beetle
Cryptolestes ferrugineus
Rusty Grain Beetle
Oryzaephilus surinamensis
Sawtoothed Grain Beetle
Plodia interpunctella
Indianmeal Moth

14. Insect Samples 7.0 x 10.2 cm cotton muslin tea bags with drawstring
Bags placed in bins for 1, 2, 3, and 4 days exposure
Beetle adults and P. interpunctella larvae were assessed upon removal
All grain particles and dust placed in g glass jars and held at 28°C
P. interpunctella eggs evaluated after 1 week and pupae after 2 weeks
Beetle progeny counted at 2 and 4 weeks

15. Percent Mortality for P. interpunctella (Indian Meal Moth)
Eggs
Larvae
Pupae

16. Percent Mortality Mean No. Progeny
Eggs
R. dominica: LGB
S. oryzae: rice weevil

17. Percent Mortality Mean No. Progeny
R. dominica
T. castaneum:
Red flour beetle
R. dominica
T. castaneum
Eggs
C. ferrugineus:
Rusty Grain Beetle
S. oryzae
C. ferrugineus
S. oryzae

18. Percent Mortality Mean No. Progeny
O. surinamensis: Sawtoothed grain beetle

19. Missouri Fumigation Training January 10 – 11, 2010
We have…Alternatives
Eggs and larvae of Indianmeal Moth were only moderately controlled and pupae were the most sensitive to ozone treatments
Overall, adult beetle mortality increased with increasing time of exposure although 100% mortality was only realized for Rice Weevil and Red Flour Beetle
Total suppression of progeny production was only seen for Red Flour Beetle at the high ozone concentration
To obtain total control, either the ozone concentration should be increased or the time of exposure increased
Missouri Fumigation Training January 10 – 11, 2010

20. Missouri Fumigation Training January 10 – 11, 2010
Using Heat to
Disinfest
Concrete Silos
-Good afternoon
-My presentation will be focused on a study we conducted in Marshall, OK in spring 2008 to investigate the efficacy of heat treatment for the control of stored product insect pests in empty concrete silos
Missouri Fumigation Training January 10 – 11, 2010 20

21. Using Heat to Kill Insects
Attractive alternative
Eliminates some of the concerns
No residues
No transportation of product; heat generated on-site
No storage issues of dangerous chemicals
Shorter down-time
Heat is a good alternative because (read)
We do not have to worry about transporting and storage of dangerous pest management products because heat is produced at the site,
Shorter down-time – desired conditions for complte control of all stages of stored-product pests is 50 C (122 F) for 8 h. This is much shorter than, for example phosphine fumigation where 200 ppm have to be maintained for 100 h (3-5 d) to achieve the same level of kill.
Takes a shorter time (usually target conditions of 50oC (122oF) for 8 hours are required)
Missouri Fumigation Training January 10 – 11, 2010 21

22. Slide shows the unit we used for our treatments in 2008.
Self-contained with its own propane tank.
What was the name of the company that supplied the heating equipment?
TEMPAIR 22

23. The unit was capable of 1.5 million BTUs/hr
Had a flow delivery rate of between 3,750-7,500 cubic feet per minute (CFM) 23

24. A flexible tubing was used to deliver heat from the heating unit into elevator silos via the drive of the elevator (point)
Flexible tubing from heater into drive of elevator. 24

25. The end of the flexible tube was attached to the bottom manhole of elevator silo.
What is the manhole typically used for? Clean the bottom of elevator. Top one for air escape when elevator is being filled. 25

26. Before the flexible tube was attached to the bottom manhole of the elevator silo, this Y tube was first placed inside the manhole and attached to the end of the flexible tube.
Y-tube inside silo to distribute the heat. Cutting holes in tube.
What is the relationship between the flexible tube going into the manhole and the Y-tube?
Should this slide come before the previous one? 26

27. Before the Y-tube was placed in the manhole, holes were cut in the tube to facilitate heat distribution. 27

28. This slide shows that the Y-tube is still able to maintains its shape after holes were cut into it.28

29. Bin Selection for Heating Study
Day 1
Heat
Day 2
Control
Day 3
Control
This bin board diagram shows the concrete silos present in the elevator complex where the study was conducted
Bin board diagram showing pairs of bins for treatments.
-Elevator used had 10 silos as shown in this bin board diagram
-But only six were used for the study
-We had 2 treatments – control treatment and heat treatment
-The experiment had 3 temporal replications over 3 days (mention silos used each day)
-The silos were 99 feet tall and insects were placed at the top, 33 ft down from the top, 66 feet down from the top, and the bottom (99 feet down from the top)- to check whether heat was effective in all locations.
The slide shows how the treatments were allocated to the 6 silos used over the 3-day duration of the experiment.
Day 1
Control
Day 3
Heat
Day 2
Heat 29

30. Insects Evaluated Rhyzopertha dominica Lesser Grain Borer
Tribolium castaneum
Red Flour Beetle
Psocids
R. dominica is the most prevalent internally infesting insect pest and T. castaneum is one of the most prevalent externally infesting insect pest in stored grain
We also used psocids because psocids have emerged as important stored-product pests worldwide over the last 15 years 30

31. These slide shows the setup used to introduce insects into the silos
These top two containers had either LGB or RFB in 100g of wheat
The bottom container had 2 species of psocids in 300 g of wheat
We also monitored the temperature inside each of these containers and outside the containers because we wanted to determine whether the wheat provided insulation. 31

32. After the heat treatment each day, containers with RFB and LGB were held in a growth chamber at 28 C (82 F) and 70% RH.
Psocid mortality was immediately assessed after the heat treatment each day.
In the case of the beetles tested
What numbers are we talking about? 32

33. -To be effective at killing all stages of the beetle pests, the insects need to be exposed to target conditions of 50oC (122oF) for 8 hours
-Temperature graphs with orange line at 50 C which was the target temperature. Once the temperature reached 50 C, then timed the exposure for 8 hours.
-The figure shows that at the top we were way off from achieving that target. At 33 feet down from the top we were slightly off from the target.
Temperature of the ambient air was always several degrees higher than temperature inside containers containing insects. This shows that wheat has a strong insulating effect, even in quantities as small as 100g.
3 points: 1) Ambient temperatures always higher – insulation by wheat; 2) More wheat more insulation; 3) less heat is getting to the top. 33

34. Percent Survival of RFB Adults
At all levels (heights), heat treatment resulted in 100% mortality of RFB adults 34

35. Percent Survival of LGB Adults
At the top and 33 feet down from the top, where we did not attain the target 122 F for 8 h, heat treatment failed to produce 100% mortality. At 66 and 99 feet down from the top, where target conditions were attained, 100% mortality occurred. 35

36. Progeny Production of RFB
Few RFB progeny were found in samples placed at the top where target conditions were not attained. High numbers of progeny were found in the control samples.
At the three bottom levels, we found that heat treatment resulted in 100% mortality of immature RFB. However, a few RFB immatures survived the heat treatment
at the top where target conditions were not attained. 36

37. Progeny Production of LGB
There was 100% kill of immature LGB at the bottom two levels. However, considerably large numbers of LGB progeny were found in samples at the top and 33 feet down from the top – levels where target conditions were not attained. High numbers of progeny were found in the control samples.
A large number of immatures survived at all levels in the control. 37

38. Percent Adult Survival of L. decolor
Despite the fact that psocids are tiny soft-bodied insects, we found 40% survivorship of L. decolor at the top level where target conditions were not attained. At other levels, heat treatment resulted in 100% mortality.
There was at least 75% survivorship at all levels in the control. This depressed survivorship in the control could be due to the low RH conditions that existed in the silos. 38

39. Percent Adult Survival of L. corrodens
Heat treatment resulted in 100% mortality of adult L. corrodens at all levels. Perhaps indicating L. corrodens is more sensitive to elevated temperatures than L. decolor.
There was at least 50% survivorship at all levels in the control. The low RH conditions that existed may account for this low survivorship in the control. 39

40. Missouri Fumigation Training January 10 – 11, 2010
Propane Usage
Average of 76 gallons propane per 99’ silo
Cost per gallon was $3.00 on May 1, 2008
Total cost per silo was $228.00
Equivalent phosphine pellets to treat silo
4,000 – 18,000 pellets per silo
$ $ based on a cost of $300 per case of 21 flasks of pellets
We then compared the cost of controlling insects in concrete silos using heat and using phosphine.
At the prevailing prices in the spring of 2008, the total cost of treating a single silo using heat was calculated as $228
Whereas the highest amount for the use of phosphine was $155.
If phosphine-resistant stored-product insects are present and need to be eliminated for the continued use of phosphine, then the cost of using heat is justifed.
The same is true if heat is being used to slow the development of resistance to commonly used pesticides.
So how does heat treatment compare with phosphine treatment?
Based on the prevailing cost of gas at the time, it cost $228 to heat each silo
Based on the prevailing cost of phosphine at the time, the highest $$ amount for phosphine trt would be $155 per silo
Overall, phosphine use cheaper
Read
The cost of heat treatment may be justified under conditions where the treatment is being conducted in order to eliminate local phosphine-resistant populations in order to allow for continued use of phosphine in the future.
Why is there such a wide range in the number of phosphine pellets required?
Sealability of the structure
Insect species and life stage
Whether grain is for keeping (high) or marketing (low) – just to meet GIPSA standards of not infested
Missouri Fumigation Training January 10 – 11, 2010 40

41. Missouri Fumigation Training January 10 – 11, 2010
We have…Alternatives
Ethylene “apple gas”
Background and idea
ANG in Afghanistan
Early testing
Killed insects
Predictions
Missouri Fumigation Training January 10 – 11, 2010

42. Missouri Fumigation Training January 10 – 11, 2010
We have…Alternatives
Manage through IPM
Identify your insects
Keep informed of new methods being tested and results
Missouri Fumigation Training January 10 – 11, 2010

43. Missouri Fumigation Training January 10 – 11, 2010
We have…Alternatives
Questions
Carol Jones, PhD, PE, Oklahoma State University Stored Products Research and Education Center
Missouri Fumigation Training January 10 – 11, 2010