Pest description, crop damage and life history
Pest Monitoring Infested soil can be treated with insecticides, but the effect is limited because of the symphylan's ability to migrate deep into the soil. Insecticides may help give the plants a chance to establish in a protected zone. In general, preplant field evaluation for symphylans involves grid sampling at one acre intervals, digging 6 x 6 x 12 inch holes (0.25 cubic foot), spreading and carefully examining the soil from the hole, and using an action threshold of 0.5 to 1 symphylans per sample. In Ohio, 50 to 100 symphylans per corn plant is considered damaging to early corn.
Many organisms prey on symphylans in the field, including true centipedes, predatory mites, predaceous ground beetles, and various fungi. However, little is known about their effect on symphylan populations.
Symphylan damage generally is associated with soils that are high in organic matter content and have good soil structure. Symphylans do not thrive in either compact or sandy soils, because these soils do not provide them with adequate tunnels for their movement (symphylans cannot make their own burrows). There is some evidence that packing down the soil surface after planting may reduce injury.
Flooding for 2 to 3 weeks has controlled symphylans in some situations but has been unsuccessful in others. Even in the best circumstances, flooding only reduces populations, and they can increase when conditions are again favorable. Effectiveness of rotations with non-host crops has not been studied.
Management-chemical control: HOME USE
Management-chemical control: COMMERCIAL USE
- chlorethoxyfos (Fortress) at 0.15 to 0.225 oz ai/1,000 row ft. REI 48 hr, or 72 hr if annual rainfall is less than 25 inches.
- chloropicrin (Telone)-Preplant.
- chlorpyrifos (Lorsban 15G) at 0.075 lb ai/1,000 row ft. PHI 21 days. Apply at planting as a band treatment. Incorporate 0.5 to 1 inch. Only one application per year. Toxic to fish.
- Isaria fumosorosea Apopka Strain 97 (PFR-97)-Naturally occurring fungus with broad insecticidal properties. OMRI-listed for organic production.
- ethoprop (Mocap 15G) at 1.2 oz ai/1,000 row ft. Rates for Mocap depend upon row spacing. Refer to label. REI 48 hr, or 72 hr if annual rainfall is less than 25 inches. Apply as a band on row or closed seed furrow, or sidedress from planting to lay-by.
- terbufos (Counter 15G) at 0.056 to 0.075 lb ai/1,000 row ft. PHI 60 days for ears, 30 days for grazing or forage. REI 48 hr, or 72 hr if annual rainfall is less than 25 inches. Apply as band or in-furrow at planting. Use the 1.2 oz rate in furrows or the 2.4 oz rate as a band. Do not exceed 1.3 lb ai/a.