Symphylans eat fine root hairs, thereby interfering with water and nutrient absorption. Your plants may be stunted; they may wilt easily and may not respond to fertilizer.

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Symphylans

Diagnose symphylans in your garden

You've done everything right, but your vegetable garden still looks wimpy. 

It may be symphylans in your soil.

A scourge of organic gardeners, these tiny centipede cousins live in the soil, where they feed on germinating seeds and roots and poke pinholes in carrots, beets, bulbs and potatoes. In fact, there are very few plants that symphylans won't attack, according Lynn Royce, OSU entomologist.

Symphylan populations are localized, damaging plants here and there in a garden or farmer's field. Large numbers can cluster in a small area. 

Symphylans eat fine root hairs, thereby interfering with water and nutrient absorption. Your plants may be stunted; they may wilt easily and may not respond to fertilizer. Yields are lower, and fruit and vegetable maturity is delayed.

Control of symphylans is tricky, even for commercial growers using soil-based insecticides. The tiny invertebrates move up and down in the soil, away from disturbance. They are especially at home in soils high in organic matter.

If you suspect you have symphylans, sprinkle about a quart of garden soil into a bucket of water. The symphylans should float on the surface. 

Don't mistake symphylans for the larger centipedes, which are often beneficial predators. 

Symphylans are white and much smaller - only a quarter inch long. They have six to 12 pairs of legs, depending on their level of maturity, and relatively long antennae.

Too small to make their own tunnels in the soil, tiny symphylans travel via earthworm burrows, cracks in the ground and the pores of otherwise healthy soil. They prefer loamy clay soils because tunnels stay intact. In sandier soil, small tunnels collapse and are no use to symphylans.

Once you have verified the presence of symphylans, the most effective remedy is to till your garden soil well next spring. This breaks down the runways in the soil and the symphylans cannot move around.

source: extension.oregonstate.edu