How to Manage Pests
UC Pest Management Guidelines
Spinach Crown Mite
Scientific name: Rhizoglyphus sp.
In this Guideline:
Spinach crown mites are tiny, almost transparent mites with
prominent long hairs, or setae. They are soil and leaf dwelling. Above ground,
they live deep in the crown of the spinach plant. Crown mite eggs are
transparent and spherical and arelaid
in the innermost parts of the plant. Immatures are similar to adults except
smaller in size.
Crown mites may damage sprouting seeds, seedlings before or after
emergence, or older plants. They feed primarily on newly expanding leaves at
the heart of the plant. Their ability to injure the crop decreases as plants
get larger and as plants grow rapidly. The damage appears as deformed leaves or
as small holes in expanding leaves.
Numerous predatory mites prey on crown mites in the field. However,
little effect is usually seen on crown mite populations.
Crown mite damage is generally associated with soils that are high
in organic matter and cool, wet conditions. Prompt destruction of harvested
fields and good sanitation of fields before planting may reduce mite
populations. Effectiveness of rotations with nonhost crops has not been
Biological and cultural control and treatments with azadirachtin are
acceptable for use on organically grown produce.
Monitoring and Treatment
Treat fields if damage is seen and cool, wet weather conditions
|The following materials are listed in order of usefulness in an
IPM program, taking into account efficacy,
information related to natural
enemies and honey bees, and
environmental impact. Not all registered pesticides are listed. Always read label
of product being used.
||MODE OF ACTION GROUP NUMBER1: 18B
||COMMENTS: Provides marginal control of crown mites. In an
organically certified crop, check with certifier for restrictions regarding the use of this product.
UC IPM Pest Management Guidelines: Spinach
UC ANR Publication 3467
Insects and Mites
S. T. Koike, UC Cooperative Extension, Monterey County
M. LeStrange, UC Cooperative Extension, Tulare County
Acknowledgements for contributions to Insects and Mites:
W. E. Chaney, UC Cooperative Extension, Monterey County
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