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Symphilids - white invertebrates in pasture root systems

Reports of small, white centipede-like invertebrates have been found closely associated with the damaged root systems of an establishing pasture

Symphilids on the root system of a wheat plant (Source: Mark Golder)

 

Where have they been reported?

Reports of large numbers of small, white to cream invertebrates about 5-8 mm long have been reported closely associated with patches of seedling failure in an establishing clover/phalaris pasture in the near Corryong, in North East Victoria. These appear to be symphilids (possibly Scutigerella spp.) and were all found just below the soil surface. During 2014, symphilids were also found attacking establishing cereal crops around Young and Cootamundra in the South West Slopes district of NSW and were the first symphilid reports to the PestFacts Service. So far, all reports of symphilids to PestFacts have been from within the 600-900 mm annual rainfall zone.

About Symphilids

Symphilids are not common pests in Australia and are more frequently associated with Australian horticulture than grains. Reports from the USA and New Zealand, where they are more common, suggest that ‘garden symphilids’ are found mainly in moist, open-structured soils often containing plant/crop debris. Detailed information can be found at the Vegetables Victoria website and Massey University - Guide to New Zealand Soil Invertebrates.

Symphylans are not insects; they are more closely related to centipedes and millipedes. The garden symphilid (also known as Symphylan in the USA) are small, white, soft-bodied ‘centipede-like’ invertebrates, 3-7 mm long with 12 pairs of legs and a pair of antennae. The notable antennae are long and many-jointed. The soft, white body is divided into 14 segments, 12 of which bear pairs of hook-like legs. All of the legs on one side move simultaneously, alternating with those on the opposite side, thus producing a twisting and turning motion. They are sensitive to light and become very active when exposed.

Importantly, symphilids feed on the root hairs of plants and can also tunnel into the roots and stems leading to stunting and plant loss. They are known to feed on sprouting seeds and underground stems of seedlings. Depending upon the extent of feeding, plants are weakened or killed. On lucerne, symphilids are known to chew off the hair roots and prevent development of a healthy root system.

Our advice

There is nothing known about control options for symphilids in Australian cropping and pastures. We drew the following recommendations from New Zealand literature. To check for symphilids, turn over at least 10 shovels of soil. Sift the soil while looking for active symphilids. Some research suggests that an average of 1 symphilid per shovel of soil may warrant chemical treatment of the infested area before planting the next crop. Mark off the infested area; the entire paddock need not be treated. Numerous naturally occurring organisms prey on symphilids in the field including true centipedes, predatory mites, predacious ground beetles, and various fungi; however, nothing is known about their ability to control symphilid populations.

 

Sources of field reports

Bruce Saxton - Grower (North East Victoria)

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