Heterodera glycines Ichinohe - Soybean Cyst Nematode

Systematic position.

Phylum Nematoda, class Secernentea, order Tylenchida, suborder Hoplolaimina, superfamily Hoplolaimoidea, family Heteroderidae, genus Heterodera.

Biological group.

Obligate parasite.

Morphology and biology.

H.glycines is characterized by sexual dimorphism; female is lemon-shaped, white (1-1.5 x 0.2-0.6 mm), male is vermiform, transparent (1-1.5 mm). Eggs are reniform (0.12 x 0.044 mm); pre-parasitic larvae of 1st and 2nd instars (0.35 x 0.48 mm) develop there. They are vermiform, being rolled inside the eggs. The eggs remain in cysts 3 years. The cyst is a dead female with hard external cover of brown color. The cysts are located in soil; in spring the larvae go out, move within wet soil, find the roots of plant hosts (soybean, vetch, lathyrus, chickpeas, peas, alfalfa, lupine), and invade them. Biological cycle takes place there; the larvae become sedentary, their head end is placed toward conducting bundles, and tail end to root bark. The larvae molt and grow during feeding; the middle part of their body thickens greatly and head and tail ends remain vermiform. These are parasitic larvae of 3 and 4 instars. The latter develops into lemon-shaped females or males (rolled inside the cuticle). The swollen bodies of the larvae break off the root bark. Males go out from larval cuticle and penetrate soil where they find the protruding tail ends of the females, inseminate them and die. Females with head end remaining in the roots continue feeding and produce eggs. The eggs are gradually laid in yellow gelatinous matrix, forming "egg sack". Invasive larvae develop in the eggs, and the biological cycle repeats. H.glycines has 3 generations during a vegetation period. In autumn the females are converted into cysts containing 500 larvae and spreading with soil. The roots parasitized by the nematode develop many small rootlets, becoming "shredded". The visible symptoms of plant infestation are stunt, dwarfism, yellow leaves, absence of fruits. This disease is called "yellow dwarf disease". Such plants are compactly situated in the field as a result of the initial ingress of cysts, their accumulation in the soil, and gradual extension of the focus. With time the foci extend all over the field area.


The Soybean Cyst Nematode is found in Amur Region and Primorskii Territory in 1970s. The surveys conducted in that period detected the pest wide distribution in the fields of soybean growing zone, high population density in soil (to 60,000 larvae per 100 g), and therefore large yield losses. Apparently, the nematode cysts were brought from the countries of Southeast Asia (Korea, China, Japan), where H.glycines was one of the main harmful pests (as in the USA). The Soybean Cyst Nematode is not detected in the European part of Russia in regions of soybean growing, as well as in the countries of the former USSR.


The species is inadequately investigated. The temperature limits are 10-31C for the nematode development in soybean roots under the conditions of the Russian Far East.

Economic significance.

The decrease of soybean yield results from poor growth and development of plants because of the infestation of their roots by the nematodes. The disease development and yield losses are caused by pre-sowing infestation of the soil. Thus, when the number of larvae in 100 g of soil amounts to 1,800, the yield decreases by 33%; 3,600 larvae per 100 g of soil reduce the yield by 58%, and 60,000 larvae decrease it by 96%. For example, in 1976 in Amur Region the soybean yield losses amounted to 560 kg/ha in the field area of 10 ha where the root infestation was 150 females per plant. To reduce the severity of H.glycines, such measures are necessary, as soybean growing in the fields with poorly infested soil that can be reached by growing unaffected crops (cereals, perennial grasses, clover, buckwheat) for 2-5 years and then using tolerant soybean cultivars (Amurskaya 456, Amurskaya 471).

Reference citations:

Glotova L.E. 1977. Nematodes of soybean and grain crops in Amur Region. Blagoveshchensk: Amur Agricultural Institute. 65 p. (in Russian)
Glotova L.E. 1979. Soybean cyst nematode that causes plant disease. Zashchita rastenii. 8: 36-37. (in Russian)
Glotova L.E. 1987. Soybean cyst nematode in the Far East. In: Reifman V.G., ed. Ways of enhancing production in plant cultivation, forage crop growing and horticulture in the Far East. Vladivostok: DVO AN SSSR.197-204 p. (in Russian)
Glotova L.E., Vlasenko E.V. 1986. Resistant and tolerant soybean cultivars and lines to soybean cyst nematode in Amur Region. In: Fadeev Yu.N., ed. Proc. VIII All-Union meeting on the immunity of agricultural plants to diseases. Part 1. Riga: VASKhNIL - Baltic branch of VIZR. 241-242 p. (in Russian)

© Gus'kova L.A.

Picture © Gus'kova L.A., Limantseva L.A. & Glotova N.E.

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