How to Manage Pests
UC Pest Management Guidelines
In this Guideline:
Garden symphylans, also called garden centipedes, are slender, white
arthropods, closely related to insects, about 0.33 inch (8 mm long), with 10 to
12 prolegs and distinct antennae. These fast-moving arthropods live in soil and
move up and down in the soil profile in relation to the moisture gradient.
After an irrigation they are near the soil surface. As the soil dries, they
move deeper. They hide when exposed to light. They occur mainly in soil with
high organic matter and especially in organic farms that fertilize with
manures. Symphylans are long lived; some adults may live several years. They move long distances in the soil
profile (up to 3 feet below the soil surface), yet cannot tunnel through soil
but must rely on existing soil pores.
They do not thrive in either compact soil or sandy soils because these
soils do not provide them with adequate tunnels for their movement.
Garden symphylans feed on decaying as well as living plant
material. They may damage
seedlings (before or after emergence) or older plants. They slow growth by
feeding on root hairs and small roots and feeding damage on older roots may
provide entryways for pathogens. Damage usually is concentrated in relatively
small areas and recurs every season; infestations spread slowly.
This pest usually occurs in relatively small areas and in soils
with a high organic matter. Reduce organic content and monitor known trouble
spots to determine the need for spot treatments.
Reduce the amount of undecomposed plant material or manure that
is applied to the soil. Wait to seed until soil-incorporated weeds or manure
has been broken down. Planting a higher seed population in problem areas may
help compensate for damage.
Cultural control is an organically
acceptable management tool.
Monitoring and Treatment
Research from other areas of the country indicates that
symphylans can be detected with bait trapping. Either carrots or potatoes can
be used as bait. Cut the bait in half longitudinally and scratch the cut surface
just before placing it on the soil to ensure that the surface is moist. Place
the bait at a depth where the soil is moist, and cover it with a plastic cup to
exclude light and prevent the soil from drying. Use at least a dozen bait traps
in the field. After 2 to 5 days, examine the cut surface and the soil upon
which it was resting for evidence of symphylans. If they are detected, consider
a treatment. If large numbers are detected (more than 20 per bait station),
consider planting the field to a different crop.
Infested soil can be treated with an insecticide, but its effect
is limited because of the symphylan's ability to migrate deep into the soil.
Insecticides may help in giving the plants a chance to establish in a protected
zone. Treat for symphylans just before planting. Spot treatments may be
|The following materials are listed in order of usefulness in an IPM program, taking into account efficacy and impact on natural enemies and honey bees. When
choosing a pesticide, also consider information relating to environmental
impact. Not all registered pesticides are listed. Always read label of product being used.
||(Warrior with Zeon)
||3.2 fl oz
||MODE OF ACTION GROUP NUMBER1: 3
||COMMENTS: PHI is 7 days for succulent shelled or edible podded crops and 21 days for dried shelled crops.
||MODE OF ACTION GROUP NUMBER1: 3
UC IPM Pest Management Guidelines: Dry
UC ANR Publication 3446
Insects and Mites
L. D. Godfrey, Entomology, UC Davis
R. F. Long, UC Cooperative Extension, Yolo County
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