This stored grain pest control presentation was given at the 2nd All Africa Post-Harvest Congress & Exhibition. The focus of the presentation was on pest control in stored maize (corn) using physical disturbance. The lead researchers from Iowa State University, who prepared this presentation, are making it available via the Consortium for Innovation in Post-Harvest Loss and Food Waste Reduction slideshare account. Iowa State University is a member of the Consortium.

1. Agricultural and Biosystems Engineering
“…to me the single greatest challenge in human history is
whether we can sustainably feed the 9 billion people who
will inhabit our planet by the year 2050…”
Dr. Kenneth Quinn, President, World Food Prize

2. Agricultural and Biosystems Engineering
Insect Pest Control through
Disturbance of Stored Grain
C. J. Bern, D. Bbosa, T. J. Brumm, R. A. Suleiman
K. A. Rosentrater, T. S. Rau, D. E. Maier,
R. B. Barnes, M. A. Friedmann, Mike Sserenjogi
Iowa State University, Ames, Iowa, USA
Sokoine University, Morogoro, Tanzania
Sukup Manufacturing Company, Sheffield Iowa
2nd All Africa Postharvest Congress and Exhibition
September 17- 20, 2019
Addis Ababa, Ethiopia

4. Agricultural and Biosystems Engineering
Maize = Corn

5. 5 9/25/2019 Add a footer

6. Agricultural and Biosystems Engineering
Background
Maize Wheat
• Staple food crops
• Major sources of income

7. Agricultural and Biosystems Engineering
Postharvest grain losses
• 18 to 22% loss in Africa
• Without proper management: 100% loss
• Loss reduction costs less than increased
production

8. Agricultural and Biosystems Engineering
Maize weevil in stored maize
Sitophilus zeamais (maize weevil)

9. Agricultural and Biosystems Engineering
L
e
s
s
e
r
G
r
Lesser grain borer in stored wheat

10. Agricultural and Biosystems Engineering
Disturbance
Controlling insects in stored grain by
physically disturbing
the grain

11. Agricultural and Biosystems Engineering
Disturbance
.
Bean tumbling as a control measure for the
common bean weevil, Acanthoscelides objectus
M. E. Quentin, J. L. Spencer, J. R. Miller 1991

12. Agricultural and Biosystems Engineering
Experiment 1: Container rotation
Objective:
Determine effectiveness of container rotation for
control of weevils in stored maize

13. Agricultural and Biosystems Engineering
Container Rotation Experiment
2.6-L Recycled ground coffee containers

14. Agricultural and Biosystems Engineering
Container Rotation Experiment
• Containers loaded with 1kg of maize + 25
weevils
• Disturbed containers rotated 1 rev every 12 h

15. Agricultural and Biosystems Engineering
25
11
15
40
44
25
6
1 1
3
0
5
10
15
20
25
30
35
40
45
50
0 days 40 days 80 days 120 days 160 days
Numberofliveweevilsperkgmaize
Time
Live Maize Weevils
Control
Disturbed
Container rotation

16. Agricultural and Biosystems Engineering
Experiment 2: Container shaking
Objective:
Determine effectiveness of container
shaking for control of weevils in stored
maize

17. Agricultural and Biosystems Engineering
Field trials in three Tanzanian villages

18. Agricultural and Biosystems Engineering
Container shaking experiment in Tanzania
• 20-L plastic containers, not sealed
• Treatments: Disturbed, Control
• Farmers shook containers morning and night

19. Agricultural and Biosystems Engineering
Container shaking
6 14
143
279
4 5 2 0
0
50
100
150
200
250
300
0 days 30 days 60 days 90 days
Numberofliveweevilsperkgmaize
Time
Live Maize Weevils
Control
Disturbed

20. Agricultural and Biosystems Engineering
Experiment 3: Stirring maize with weevils
Objective:
Determine effectiveness of stirring for
control of weevils in stored maize

21. Agricultural and Biosystems Engineering
Sukup Stirring Machines
• Stirring:
– Mixes grain during drying
– Eliminates pockets of high-moisture grain
– Increases airflow

22. Agricultural and Biosystems Engineering
Experimental Stirring Machines
Unstirred Control Container
Stirred Container

23. Agricultural and Biosystems Engineering
Methods and Materials
• Laboratory Chamber
– 27℃
• Stirring Machines
– Stir every 12h
– One length of the container
• Storage Containers
– Volume 0.12𝐦 𝟑
– Length 104cm
• Sample by Probing
– 40 day intervals

24. Agricultural and Biosystems Engineering
Stirring maize
25
1.67
18
25
0 0
0
5
10
15
20
25
30
0 days 40 days 80 days
Numberofliveweevilsperkgmaize
Time (days)
Live Maize Weevils
Controlled
Stirred

25. Agricultural and Biosystems Engineering
Experiment 4: Stirring wheat with grain borers
Objective:
Determine effectiveness of stirring for control of
lesser grain borers in stored wheat

26. Agricultural and Biosystems Engineering
Experimental Design
• Wheat moisture 13%
• 30kg of wheat
• 25 adult lesser grain borers/kg wheat
• Two treatments (stirred/unstirred)
• Three replications

27. Agricultural and Biosystems Engineering
Methods and Materials
• Laboratory Chamber
– 27℃
• Stirring Machines
– Stir every 12h
– One length of the container
• Storage Containers
– Volume 0.12𝐦 𝟑
– Length 104cm
• Sample by Probing
– 40 day intervals

28. Agricultural and Biosystems Engineering
Stirring Wheat
25
11
115
75
25
0 1
8
0
20
40
60
80
100
120
140
0 days 40 days 80 days 120 days
NumberofliveLGBsperkgwheat
Time (days)
Live Lesser Grain Borers
Controlled
Stirred
Stirring Disabled

29. Agricultural and Biosystems Engineering
Conclusions
• Physical disturbance works
• Grain quality is OK*
• Disturbance may be appropriate for
chemical free stored grain insect
control
*Stirring may create fine material

30. Agricultural and Biosystems Engineering
Future Work
• What is the most effective disturbance
interval?

31. 31 9/25/2019 Add a footer

32. Disturbance machine in operation
Agricultural and Biosystems Engineering
Jars rotated every 8, 12 or 24 hours

33. Agricultural and Biosystems Engineering
8, 12, 24 hour disturbance intervals

34. Agricultural and Biosystems Engineering
Future Work
• What is the most effective disturbance
interval?
• Will stirring work in full-size bins?

35. Agricultural and Biosystems Engineering
Sukup Stirring Machines
• Stirring:
– Mixes grain during drying
– Eliminates pockets of high-moisture grain
– Increases airflow

36. Agricultural and Biosystems Engineering
Future Work
• What is the most effective disturbance
interval?
• Will stirring work in full-size bins?
 Why does disturbance work????

37. Agricultural and Biosystems Engineering
We are grateful to Sukup Manufacturing
Company, Sheffield, Iowa USA for their
support of this research.

38. Agricultural and Biosystems Engineering
Discussion