Eurygaster austriaca Schrank - Sunn Pest

Systematic position.

Class Insecta, order Hemiptera, family Scutelleridae, genus Eurygaster.

Biological group.

Oligophagous pests of cereals.

Morphology and biology.

The broadly ovoid body of imago is light brown or red brown, finely punctate. Its length varies from 11 to 13 mm. Pointed head as long as wide. Tylus shorter than cheek plates, often closed. Sometimes cheek plates form a cleft. Lateral borders of pronotum are prominent. Scutellum has high, smooth comb without tubercles. Larvae and imago are similar, but larvae are small, wingless. Globular eggs are light-green at first then brown, about 1 mm in diameter. Overwintering takes place at the imago stage under fallen leaves in forests, under trees and bushes. Bugs prefer mountainous places. Awakening is observed at the end of April and the beginning of May at the temperature 19-20°C (later than that of E. integriceps). Additional feeding is necessary for bugs. Insects populate perennial cereal grasses, living openly. Coupling takes place in May, and oviposition in June. Bugs lay eggs by regular rows into the drop of excretion on lower side of leaves or stems. Fecundity of one female varies from 20 to 28 eggs (1.5 times less than that in E. integriceps). Embryonal development lasts 14 days. Larva has five instars. The first instar larvae are not mobile, locating among scales of ears; older instar larvae crawl along plants, looking for food. Larvae and young bugs feed on grains. Larval stage lasts about one month. The bugs fly the middle of July and they migrate to forests at the beginning of August. Migration lasts during September and October. This species is marked on fields at a small number usually, but sometimes its numbers increase.


The insect is distributed in South and Middle Europe, North America, Anterior Asia. Within the territory of the Former Soviet Union, the species occurs northward to Byelorussia, Kursk, Tambov, Penza Regions. The bug is marked in the middle band and in the southern area of the European part. Its high harming activity appears in forest-steppe zone; the pest occurs seldom in steppe zone and in the Southeast of the European part.


This species is mesophilous. Insects essentially perish during cold damp winters with small snow covering. In spring, awakening bugs endure frequent changes of temperature and abundant precipitations. The most favorable conditions are the temperatures 25-27°C and the relative humidity 60-80%. The pest prefers dense crops (with high humidity), feeding also on perennial cereal grasses. During droughty years, it sometimes migrates actively to crops. The species gives one generation during a year. The most important predators are Microphanurus vassilievi Mayr., M. cultratus Mayr., Cystogaster globosa Fln., Helomyia lateralis Meig., Cylindromyia auriceps Meig., C. intermedia Meig., Rhodogune rotundatum L.

Economic significance.

The insect feeds on perennial cereal grasses, also on wheat, rye, barley, oats, maize, sorghum. Leaves become yellow and dry up, causing the plant to lag in its growth. Larvae and bugs feed on ears, which is most dangerous to grain. The ears have small grains that become puny, and flour loses its baking quality. The species is not as dangerous as E. integriceps because its awakening is marked later and its fecundity is not high. Control measures include eradication of weeds, early harvesting of grain, under-winter plowing, insecticide treatments against both imagoes and larvae at their essential numbers.

Reference citations:

Arkhangel'skii, N.N. 1946. Materials to studying factors regulating Eurygaster bug numbers. In: Zakharov, S.A., ed. Proceedings of Rostov State University. Rostov-on-Don: State University, p. 37-38 (in Russian).
Kerzhner, I.M. & Yachevskii, T.L. 1964. Order Hemiptera - bugs. In: Bei-Bienko, G.Ya., ed. Keys to insects of the European part of the USSR. V. 1. Moscow & Leningrad: Nauka, p. 830 (in Russian).
Kosov, V.V. & Polyakov, I.Ya. 1958. Forecasting and calculation of pests and diseases on agricultural crops. Moscow: Agricultural Department, p. 250-251 (in Russian).
Migulin, A.A. 1983, ed. Agricultural entomology. Moscow: Kolos, p. 76-77 (in Russian).
Nurmuratov, T.N., ed. 1986. Cereal protection from pests, diseases and weeds. Alma-Ata: Kainar, p. 68-70 (in Russian).
Pavlov, A.N. 1954. Damaging grains by sunn pests (Eurygaster, Pentatomidae) at the irrigation conditions. In: Oparin, A.I., ed. Reports of Academy of Sciences of USSR, 108(4): 661-663 (in Russian).
Pogorelov, M.N. 1965. Dynamics of development and species composition of cereal bugs in the eastern zone of Khar'kov region in 1964. In: Grinchenko, A.M., ed. Proceedings of Khar'kov agricultural institute, N 6. Khar'kov: Agricultural Institute, p. 11 (in Russian).
Puchkov, V.G. 1972. Order Hemiptera - bugs. In: Kryzhanovskii O.L., ed. Insects and mites - pests of agricultural cultures. V. 1. Leningrad: Nauka, p. 225-226 (in Russian).
Taranukha, M.D. 1952. Cereal bugs in forests and forest strips. In: Pogrebnyak, P.S., ed. Proceedings of Academy of Sciences of UkrSSR, N 4. Kiev: AN UkrSSR, p. 67-79 (in Russian).
Taranukha, M.D. 1954. To ecology of cereal bugs of the genus Eurygaster. In: Markevich, A.P., ed. Proceedings of Kiev State University. Kiev: State University. Part 1, p. 260-261 (in Russian).
Vasil.ev, V.P., ed. 1973. Pests of agricultural crops and forest plantations. Vol. 1. Kiev: Urozhai, p.348-350 (in Russian).

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