Description of the Pest
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.
Garden symphylans may damage seedlings before or after emergence and may slow the growth of larger plants. Damage usually is concentrated in relatively small areas and recurs every season; infestations spread slowly. In recent years symphylans have become serious pests of young, transplanted processing tomatoes in areas of the San Joaquin Valley and lower Sacramento Valley.
This pest usually occurs in relatively small areas and in soils with high organic matter. Reduce organic matter input 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 or transplant until the cover crop, soil-incorporated weeds, or manure has been broken down.
- Planting a higher seed population in problem areas may help compensate for damage.
- Rotate to tolerant crops such as beans, oats, or potatoes.
Organically Acceptable Methods
Cultural control is an organically acceptable management tool. Limited research has shown no significant control by organic soil amendments or essential oils.
Monitoring and Treatment Decisions
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 applying a pesticide.
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 their roots in a protected zone. Treat for symphylans just before planting. Spot treatments may be adequate.
|Common name||Amount per acre**||REI‡||PHI‡|
|(Example trade name)||(hours)||(days)|
|Not all registered pesticides are listed. The following are ranked with the pesticides having the greatest IPM value listed first—the most effective and least harmful to natural enemies, honey bees, and the environment are at the top of the table. When choosing a pesticide, consider information relating to air and water quality, resistance management, and the pesticide's properties and application timing. Always read the label of the product being used.|
|(Warrior II with Zeon)||1.28–1.92 fl oz||24||5|
|MODE-OF-ACTION GROUP NUMBER1: 3|
|COMMENTS: Apply to soil in a minimum of 10 gallons water/acre next to or below the transplants with standard preplant fertilizer equipment just before transplants are set out in field. Use allowed under a FIFRA Section 2(ee) recommendation.|
|(Baythroid XL)||2.8 fl oz||12||0|
|MODE-OF-ACTION GROUP NUMBER1: 3A|
|COMMENTS: Apply to soil in a minimum of 10 gallons water/acre next to or below the transplants with standard preplant fertilizer equipment just before transplants are set out in field. A maximum of one pre-transplant application is allowed per crop season.|
|(Diazinon AG 600WBC)||51–102 fl oz||48||0|
|MODE-OF-ACTION GROUP NUMBER1: 1B|
|COMMENTS: Provides inconsistent control. Broadcast just before planting and immediately incorporate into the top 4 to 8 inches of soil.|
|**||See label for dilution rates.|
|‡||Restricted entry interval (REI) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (PHI) is the number of days from treatment until harvest can take place. In some cases the REI exceeds the PHI. The longer of these two intervals is the minimum time that must elapse before harvest may take place.|
|*||Permit required from county agricultural commissioner for purchase or use.|
|1||Rotate chemicals with a different mode-of-action Group number, and do not use products with the same mode-of-action Group number more than twice per season to help prevent the development of resistance. For example, the organophosphates have a Group number of 1B; chemicals with a 1B Group number should be alternated with chemicals that have a Group number other than 1B. Mode-of-action group numbers are assigned by IRAC (Insecticide Resistance Action Committee).|