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Common Name: Panicle rice mite Scientific name: Steneotarsonemus spinki Smiley
Biology (life cycle):
Adult panicle rice mites are clear to straw-colored, oval in shape and approximately 1/100 of an inch long. Immature panicle rice mites are clear to straw-colored and about half the size of adults. Eggs are clear in color, oval-shaped, and about 1/3 the size of adults. An entire lifecycle can be completed in 7-21 days depending on temperature.
Damage:
Damage caused by mite: The panicle rice mite injures rice plants both directly by feeding on cells of rice leaves, stems and kernels and indirectly by vectoring and/or facilitating the establishment of pathogens. Feeding damage can result in a sterile grain syndrome, which is described as a loose and brownish flag leaf sheath, a twisted panicle neck, impaired grain development with empty or partially filled grains with brown spots and panicles standing erect. Malformed grains sometimes show a curved appearance, often referred to as “parrot-beak.” Damage to the leaf sheath reduces the photosynthetic potential of the plant and can have a negative effect on fertility. The heaviest and most economically damaging populations of panicle rice mite are often reported during the second or ratoon crop.
Management:
Facts: The panicle rice mite was reported in the continental United States in 2007. Significant crop losses have been attributed to this mite, particularly in the presence of sheath rot and bacterial panicle blight, in many tropical rice growing areas of the world.
What should you look for: Scout for this pest by looking for the symptoms associated with bacterial panicle blight and sheath rot. Look for a cinnamon, yellow or chocolate-brown discolored lesion on the leaf sheath that does not have a distinct edge. Examine the inside of the leaf sheath with a 30X hand-lens. Mites look like small grains of sugar to the unaided eye. Damage can often be observed on interior leaf sheaths when the outer sheath is removed. They also feed on developing panicles from the boot stage to the milk stage of heading.
How you can manage panicle rice mite: There are currently no management guidelines. Contact your extension agent if you suspect that this mite may be present in your field and to obtain the latest information on this pest.
Scouting video:
Insecticide option:
Useful links:
| | Picture 1: Panicle rice mite inside the stem by N. Hummel |
| | Picture 2: Infested plant by N. Hummel |
| | Picture 3: Panicle rice mite by N. Hummel |
| | Picture 4: Panicle rice mite – adult by USDA |
| | | Picture 5: Panicle rice mite – immature by USDA |
| | Picture 6: Panicle rice mite – eggs by USDA |
| | Picture 7: Mite injury on leaf sheath by N. Hummel |
| | Picture 8: Mite injury on leaf sheath by N. Hummel |
| | Picture 9: Mite injury on rice panicle by N. Hummel |
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