Pests
Meligethes aeneus F. - Rape Pollen Beetle
Systematic position.
Class Insecta, order Coleoptera, family Nitidulidae, genus Meligethes.Biological group.
Oligophagous pests of crucifers.Morphology and biology.
Oblong flat body of imago is black from above, with metallic green or blue shine. Its length varies from 2 to 3 mm. Prothorax is short. Elytra are covered with small punctures and fine gray hairs; they do not cover the last abdominal segment. Clavate black antenna consists of 11 segments (clava has 3 segments). Legs are short; red-brown or yellow tarsus has 5 tarsomeres. Foretibia is notched. Egg is white, oval, smooth. Gray or white-yellow larva has 3 pairs of thoracic legs. Its body (4 mm in length) is covered with small black warts bearing hairs. Segments of prothorax and mesothorax have brown horny shields on both sides. Pupa is about 3 mm in length; at first, it is light, later dark. Imagoes overwinter in the upper layer of ground or in the litter at forest edges or forest belts. The beetles emerge in April-May at the temperature 8°C and higher. Additional feeding is necessary. The beetles populate weed plants of various families, then migrate to cruciferous weeds. In June, the pest moves onto cultural crucifers. The beetles eat flower petals, pollen, pistils, stamens, nectar, and ovaries. Damaged flowers dry up. Coupling takes place in flowers, and in 3-4 days, female lays eggs (one by one) in young flower buds or in flowers. Fecundity of one female varies from 60 to 180 eggs. Embryonal period lasts 10-14 days. Larvae also eat pistils and stamens of flowers, living 3-4 weeks and molting 3-4 times. Late larvae also damage pods. During its life, a larva can damage several flowers. Pupation takes place in the upper layer of ground. Beetles of new generation appear at the middle of July.Distribution.
The insect is spread in Europe; Anterior and Middle Asia, North Africa. Within the territory of the Former Soviet Union, the species occurs widely (except the Far North). High harming activity appears in some regions of central zone of the European part of Russia, in Siberia, Ural, Ukraine, Byelorussia, and Moldova.Ecology.
Mass colonization of blooming plants is observed at the end of May and in the beginning of June at the daily air temperature 13.8-14.6°C (sum of degree days is about 239-247°C). Insects live in flowers; they prefer protection from cold winds and fields next to plots with dense weed vegetation. The insects develop at wide-ranging temperatures, but the most favorable conditions are the temperatures 21-26°C and relative humidity 70-80%. The species has one generation a year in central and northwestern regions; 2-3 in southern regions. The most important predators are: Malachius aeneus F., Microgaster sp., Coccinella septempunctata and others.Economic significance.
The pest damages rape, turnip, mustard, cabbage and others cruciferous cultures. Damaged flowers fall. Economic threshold of harmfulness is 2 beetles per plant. Five insects on one plant create yield loss of 16%, and 20 insects reduce yield by 50%. The first generation beetles are the most harmful. Control measures include eradication of weeds, winter plowing, destroying of plant residues, insecticide treatments against both imago and larvae at their high numbers.Reference citations:
Blinova V.P. 1972. Basing and improvement of control measures against rape pollen beetle (Meligethes aeneus F.) on seed crucifers in Moscow Region. PhD Thesis. Leningrad. LSKhI, 25 p. (in Russian).Bogdanov-Kat'kov N.N. 1920. Pests of seed cultures. Rape pollen beetle (Meligethes aeneus F.). Petersburg: Petersburg plant protection station, 15 p. (in Russian).
Chesnokov P.G. 1949. Bioecological features of rape pollen beetle and their significance for protection of seed crucifers. In: Eikhfel'd I.G., ed. Proceedings of Pushkin laboratories of VIR. Leningrad: VIR, p. 265-269 (in Russian).
Gar K.A., Mel'nikova A.I. 1986. Forecasting of rape pollen beetle emergence and dates of treatments. Zashchita rastenii 7: 51-52 (in Russian).
Karavyanskii N.S. & Blinova V.P. 1970. Rape pollen beetle. Sel'skoe khozyaistvo Belorussii 12: 15 (in Russian).
Karavyanskii N.S. & Mazur O.P. 1975. Pests and diseases of fodder cultures. Moscow: Rossel'khozizdat. p. 203-204 (in Russian).
Kireichuk A.G. 1979. Beetles of superfamily Meligethinae (Coleoptera, Nitidulidae) in fauna of the USSR. PhD Thesis. Leningrad. ZIN, 24 p. (in Russian).
Kosov V.V. & Polyakov I.Ya., ed. 1958. Forecasting and calculation of pests and diseases on agricultural cultures. Moscow: Agricultural Department. 539-540 p. (in Russian).
Kozhanchikov L.K. 1929. To biology of Meligethes aeneus Fabr. In: Bogdanov-Kat'kov N.N., ed. Plant protection against pests (Bull. of Bureau of Entomological and Phytopathological Congresses). Leningrad: Publishing House of Plant Protection against Pests. 560-562 p. (in Russian).
Man'kova G.S. 1977. Rape pollen beetle and testing of some insecticides for its control. In: Samsonov V.P., ed. Problems of agriculture and selection of field cultures (Proc. Byelorussian institute of agriculture). Zhodino: VNII agriculture. 193-198 p. (in Russian).
Migulin A.A. 1983, ed. Agricultural entomology. Moscow: Kolos. 211 p. (in Russian).
Pavlovskii E.N., ed. 1949. Harmful animals of Middle Asia. Moscow & Leningrad: Publishing House of Academy of Sciences of the USSR. 66 p. (in Russian).
Polyakov I.Ya., ed. 1989. Forecasting of pests and diseases on agricultural cultures in 1989. Moscow: VIZR. 145-146 p. (in Russian).
Polyakov I.Ya., ed. 1990. Forecasting of pests and diseases on agricultural cultures in 1990. Moscow: VIZR. 145-146 p. (in Russian).
Titov K.G. 1960. Protection of seed crucifers against rape pollen beetle. Sel'skoe khozyaistvo Belorussii 7: 73-74 (in Russian).
Vlasenko N.G. 1977. Rape pollen beetle. Zashchita i karantin rastenii 8: 47 (in Russian).
Vlasenko N.G. 1991. Attraction of crucifers for rape pollen beetle. In: Korobov V.A., ed. Forecasting and integrated protection against pests, diseases and weeds on agricultural cultures (Proc. of Siberian institute of agriculture and agricultural chemicalization). Novosibirsk: Siberian department of RASKhN. 40-41 p. (in Russian).
Volkov S.M., Zimin L.S., Rudenko D.K., Tupenevich S.M. 1955. Atlas of pests and diseases on agricultural cultures in the Non-Black Earth zone of the European part of the USSR. Moscow & Leningrad: Sel'khozgiz.. 164 p. (in Russian).