PISA-VET launch_El Iza Mohamedou_19 March 2024.pptx
Rice Weevil (Sitophilus oryzae)
1. AB 2111
POSTHARVEST BIOLOGY
RICE WEEVIL
Sitophilus oryzae
By
W.A.G.E.WIJELATH (AG/12/FT/024)
N.H.G.T.MADUSHANI (AG/12/FT/012)
Department of Food Science and Technology
Faculty of Agriculture
University of Peradeniya
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2. Content
• Taxonomy
• Life cycle
• Morphology
• Behaviour
• Habitat
• Signs of infestation
• Damages
• Control
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3. Taxonomy
Kingdom : Animalia
Phylum : Arthropoda
Class : Insecta
Order : Coleoptera
Family : Curculionidae
Subfamily : Dryophthorinae
Genus : Sitophilus
Species : S. oryzae
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4. Life Cycle
Consists of four stages
• Egg stage
• Larval stage
• Pupa stage
• Adult stage
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7. Pupa
• White
• Black, hard head
• Movable segments
Adult
• 2-3 mm in length
• Reddish brown to black in colour
• 4 light yellow or reddish spots on elytra
• Long, slender snout
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8. • Irregularly shaped pits on thorax
• Smooth, narrow strip extending down the middle of the back
• Fully developed wings
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9. Behaviour
• Internal feeders
• Active fliers
• Attracted to lights
• When disturbed, adults pull in their legs, fall to the ground, and
feign death
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10. Habitat
Usually found in
• Grain storage facilities
• Food processing plants
• Food markets
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11. They usually infest
• Stored rice
• Wheat
• Corn
• Rye
• Barley
• Sorghum
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12. Signs of Infestation
• Heating at the surface
• Increased moisture levels
• Seeds with round holes
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13. Damages
• Larvae develop within the seeds consuming the
endosperm
• Adults feed on whole seeds or flour
• The adult leaves a large, ragged exit hole in the kernel
• Feeding contributes to heating and infested grain is often
damp due to moisture added by the insects’ respiration
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14. Control
• Preventing the insects from entering the storage
• Pest-proof containers
• Proper bin sanitation before introduction of new grain
• Cleaning bins regularly
• Addition of dry ice
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15. • Fumigation
• Application of insecticide
• Use of natural repellents
• Locating and removing all potentially infected food sources
• Repackaging products in new uninfected packages
• Freezing infected food below -17.7°C (0°F) for three days
• Heating to 60°C (140°F) for 15 minutes
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16. Reference
• Public Health Vectors and Pests (2013) Rice Weevil [online] Available from:
http://www.kznhealth.gov.za/environ/vector/riceweevil.htm [Accessed on:
05/05/2015]
• The Pennsylvania State University (2015) Weevils on Stored Grain [online]
Available from: http://ento.psu.edu/extension/factsheets/weevils-on-
stored-grain [Accessed on: 05/05/2015]
• Canadian Grain Commission (2013) Rice weevil [online] Available from:
https://www.grainscanada.gc.ca/storage-entrepose/pip-irp/rw-cr-eng.htm
[Accessed on: 05/05/2015]
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