Symphyla

Fast moving, up to about 10mm long with 12 pairs of legs.

Nymphs look similar to adults, but have fewer legs.

Other soil-dwelling arthropods such as diplura or collembola.

Widespread and present in most soil types, with a preference for loose or cracking loams, and soils high in organic matter.

Attacks roots of a wide range of plant species. The damage is most noticeable in tap-rooted crops such as cotton, but symphyla are also considered pests of sugarcane.

• Root system development is stunted. In many cases the tap root stops growing and the subsequent root branching is often referred to as ‘witches’ broom’.
• Affected plants exhibit wilting symptoms (even in good soil moisture), general stunting, and sometimes seedling death.
• Symptoms are more prevalent if plants are stressed and cannot grow additional roots fast enough to offset the damage.
• Typically symphyla feed on roots where the soil is moist. As the moisture profile dries out, the continuous root pruning can leave plants stranded in the top 10-15cm of soil.

Symphyla are delicate—avoid compacting the soil while sampling.

• Insert a shovel to full depth at the plant line and carefully lever the soil out for closer inspection.
• Start examining soil from the bottom of the shovel, as symphyla are more common in the deeper, wetter part of the soil profile.
• Holding a soil clod in one hand, use your other hand to carefully break the soil apart while keeping a close eye on the inner surfaces for movement (they will rapidly shift to avoid sunlight).

It is difficult to target symphyla with insecticide:

• They can be active to depths of up to 1m.
• Insecticide at planting may not provide sufficient protection if roots quickly grow past the treated zone.

Non chemical management:

• Ensure that susceptible fields are planted last so that the warmer conditions aid rapid establishment.
• Monitor plant health closely, and if establishing plants show signs of moisture stress (and symphyla are present) a quick irrigation will aid plant development and allow the crop to out-grow the pest.

If more than 5 symphyla are found per shovel full of soil and establishment is poor enough to warrant replanting, consider a fibrous-rooted alternative crop such as maize or sorghum, or replant cotton in another field if possible.