Northwest berry Foundation

Management Detail

Garden Symphylan

in Blueberries

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Latin name: Scutigerella immaculata

Description:

Reason for Concern:
1) Symphylans live in the soil and feed on fine roots and can cause extensive crop damage. They can be exceptionally injurious to young plants.
2) Root feeding can reduce the bush’s ability to take up water and nutrients, which leads to general stunting.
3) Root damage may also render plants more susceptible to some soil-borne plant pathogens.

Identification/Symptoms:
Garden symphylans are tiny, white, centipede-like creatures 1/8- to ¼-inch long with 6 to 12 pairs of legs. Eggs are pearly white and spherical with hexagonal shaped ridges. The symptoms of low vigor and weak growth usually show up sometime between April and June.

Lifecycle:
Eggs, adults, and immature garden symphylans can be found together throughout most of the year. Temperature plays a key role in regulating egg laying, and the greatest numbers of eggs are usually deposited in the spring and fall. Eggs incubate for about 25 to 40 days, when temperatures range from 50° to 70°F, but hatching occurs in about 12 days as temperatures reach 77°F. First instars emerge from the egg with 6 pairs of legs and 6 antennal segments, their bodies covered with fine hairs. Slow movements and a swollen posterior make first instars appear superficially more like a springtail than an adult garden symphylan. These first instars, however, are rarely found in the rooting zone and within days molt to second instars that resemble small adult garden symphylans. Each of the 6 subsequent molts results in the addition of a pair of legs and variable numbers of body and antennal segments. Total time from egg to sexually mature adult (seventh instar) is about 2 to 5 months depending on temperature. It may be possible to have 2 complete generations a year. Adult garden symphylans may molt more than 40 times.

Links:

Scouting:

  • Weak spots in a field may indicate symphylan root feeding.
  • Sample by taking a shovelful of soil down to a depth of about 8 inches.
  • Carefully search through and count the number of symphylan present. At least one shovelful per acre should be sampled.
  • More than 5 per shovelful can indicate a problem although thresholds are not well established.
  • Symphylans can also be baited by putting out half a potato on the ground and covering it with a white pot with no holes.
  • Baiting can get variable results depending on time of year, weather and soil conditions.

 
Cultural Controls:

  • Tillage helps but is not a stand alone method.
  • Growers should avoid rotating from crops such as corn that are known hosts for symphylans.

 

For information about chemical controls, check with our Pesticide Guide.

images


photo by K. Gray


photo by D. Calvin

 

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