Pests
Melolontha hippocastani F. - Forest cockchafer
Systematic position.
Class Insecta, order Coleoptera, suborder Polyphaga, infraorder Scarabaeoidea, family Melolonthidae, subfamily Melolonthinae, tribe Melolonthini, genus MelolonthaBiological group.
Polyphagous pest.Morphology and biology.
Forest cockchafer is a beetle with fulvous scutum and brown elytrae with blackish edges. The body length is 20-29 mm. Color is quite varied. The most clear distinctive feature is shape and color of pigidium which is black and quite short. In females it forms a narrow projection and in males ends with a small rounded widening. Sexual dimorphism, besides the pigidium, is confined to notched tibia of female forelegs and number of plates of antennae, which are heptamerous in males and two times larger than in females, the latter having antennae with 6 plates. The beetle eggs are oval, sized 2-3 mm, dirty white. Larvae are whitish yellow and C-shaped. Brown head bears tetratomic antennae and strong mandibulae. There are three pairs of legs. The abdomen consists of 10 somits, the latter two of which are massive. Two parallel longitudinal rows of 22-30 chaetae are present on the last somit. Larvae have three instars distinguished by head capsule width (2.5 mm in first, 4 mm in second and 6 mm in third instar larvae). Pupa is free, colored light yellow. Young cockchafer beetles are found in soil as soon as the summer ends and hibernate there until the next spring. In southern regions they usually emerge from second half of April until beginning of June. In northern regions beetles emerge from middle of May to the end of June. Beetles fly in the edges of deciduous plantations and couple during additional feeding. An impregnated female bearing mature eggs repeatedly stops feeding and flies to the openings for laying eggs, each time using the same route. They prefer light warmed with a scarce soil layer, laying up to 70 eggs at the depth of 10-100 mm and returning to the feeding places 3-4 times. Larvae emerge after 40-50 days, from the end of June to July. Initially, they consume humus particles, then eat small roots. The most notable damage is seen by smaller and larger root injury by second and third instar larvae from May to September. Young pines and firs are the most susceptible to injury and perish during strong damaging; beet and other field crops are also damaged. Larval development lasts usually 3, sometimes 4 and 5 years. On the fourth summer, the larva pupates and in 1-1.5 months beetle emerges and remains in soil for hibernation.Distribution.
Forest cockchafer is an Eurasian species, widely distributed in forest zone of Russia from its western boundaries to Yakutia and Primorie. Northern limit of its areal crosses Tartu, Vyborg, Arkhangelsk; on the east boundary runs from Yakutia along the Pacific coast through Manchuria to Pekin. On south, it is limited on the level of Danube (in Europe), Odessa, Zaporozhye, Uralsk, Altay and Shanghai. In Russia forest cockchafer is a known pest of pine in forest and forest-steppe zones, is found in northern part of European steppe region, in Siberia in zones of taiga and forest-steppe. In Northern and Central Europe it dominates forest clearings on sandy soils. On south, it prefers places shadowed by forest plantings.Ecology.
Ecology of forest cockchafer is quite difficult due to wide diversity of climatic and soil zones constituting wide areal of the beetle. Northern part of the areal (Leningrad and Kalinin regions, northern part of Moscow region, Ivanovo, Kirov regions, Kharkov) is characterized by five-year cycle of the beetle and inhabitation of rarefied forest. Middle part of areal (from Northern boundary to Voronezh region) is the zone of optimal conditions for beetle development which mainly has 5-year cycle. Southern part of areal is characterized by 4-year cycle of development and beetle dwells under forest canopy. Natural enemies, such as moles, badgers, bats, cuckoos, woodpeckers, thrushes, magpies, rooks, jackdaws, sparrows, ground beetles, large wasps and tachinid flies, notably decrease may beetle numbers. All the maybug.s developmental stages, and especially pupae and imagoes, are submerged to infection with entomopathogenic fungi Beauveria brongniartii S. and B. bassiana B., bacteria Bacillus thuringiensis and Coccobacillus sp., microsporidia Pleistophora melolonthae H. and Telohania sp.Economic significance.
In the world agricultural practice, grubs are known as pests of many crops (plum trees, apple trees, cherry tree, berry bushes, grass plants). The third instar larvae are the most voracious, causing great damage to the young trees and especially to the fruit tree farms. Beetles eat up leaves and flowers. With the density of 5 to 40 beetles per square meter, plant damange may reach 25%. To control the cockchafers, it is recommended to stimulate growth of healthy and resistant plantings with help of soil treatment with annual or biannual fallowing, correct choice of tree and bush grade, the use of high quality seeding and planting material and to plow fields causing larvae death due to mechanical injury and submerging as the birds. prey. Beetles may be caught and destroyed using light traps. Organophosphorous insecticides are applied to the plantings after blooming during the beetle flight period and to the soil to kill larvae and to treat roots before the planting. Beauveria bassiana-based mycoinsecticides show good results as well.Reference citations:
Averkiev, I.S. 1967. Investigation of forest cockchafer in forests of Mari ASSR. In: Danilov, M.D., ed. Bull. Forestry Faculty Chairs. Ioshkar Ola: Mariiskoe knizhnoe izdatel.stvo. 3(58): 214-217 (in Russian).Berezina, V.M. 1960. Geographic zoning of habitat distribution of forest cockchafer on the territory of USSR. In: Polyakov, I.Ya., ed. Bull. All-Russ. Inst. Plant Protection. Vol. 15. Leningrad: VIZR, p. 87-128 (in Russian).
Berezina, V.M., Stark, V.N. 1936. Areal of forest cockchafer in USSR. In: Zelenukhin, I.A., ed. Res. Summ. All-Russ. Inst. Plant Protection in 1935. Leningrad: All-Union Academy of Agricultural Sciences, p. 28-32 (in Russian).
Dmitriev, G.V. 1969. Bases for protection of green plantings from the pestiferous arthropods. Family Scarabaeidae. Kiev: Naukova dumka, p. 279, 377 (in Russian).
Gavyalis, V. 1970. Distribution of beetles of the Melolontha genus in Lithuanian SSR and its flight years // In. OzolinТsh, V.Ya., ed. Pests of agricultural and forest plants and their control measures. Proc. 7 Baltic Conf. Plant Protection. P 2. Elgava: Pribaltiiskii filial VIZR, p. 68-71 (in Russian).
Gol.tsmaier, O.P. 1956. Forest cockchafer (Melolontha hippocastani F.) in forest-steppe part of Novosibirsk region. Ph.D. thesis. Novosibirsk: Tomskii gosudarstvennyi universitet, 19 p. (in Russian).
Gol.tsmaier, O.P. 1959. On drought impact on decrease of abundance and harmfulness of the forest cockchafer. In: Bei-Bienko, G.Ya., ed. Proc. 4 Congr. All-Soviet Entomol. Soc. Agricultural and forest entomology, biological pest control, apiculture and sericulture. P. 2. Moscow, Leningrad: Akademiya nauk SSSR, p. 19-21 (in Russian).
Grishina, L.G. 1966. On ecology of the forest cockchafer (Coleoptera, Scarabaeidae) of Altay. In: Cherepanov, A.I., ed. // Fauna and ecology of arthropods of Siberia. Novosibirsk: Nauka, p. 206-208 (in Russian).
Lisov, N.A. 1984. Impact of some ecological factors on place choice for oviposition of females of the forest cockchafer. In: Tsygankova, E.N., ed. Proc. 9 All-Russ. Entomol. Soc. P. 2. Kiev: Naukova dumka, p. 19 (in Russian).
Negrobov, S.O. 2000. On the fauna and ecology of stag-beetles and scarabs (Coleoptera: Lucanidae, Scarabaeidae) of Voronezhskaya region. Entomologicheskoe obozrenie 79(1): 89-95 (in Russian).
Polozhentsev, P.A., Troitskii, B.G. 1963. May beetle in the forests of Mari ASSR. In: Koperin, F.I., ed. News of higher education institutions. Lesnoi zhurnal. Arkhangel.sk: Arkhangel.skii lesotekhnicheskii institut, p. 35-38 (in Russian).
Rozhkov, A.A. 1968. Forest cockchafer as the main pest of pine crops in Tyumen region. In: Kataev, O.A. Forest protection. Sci. Labors. Leningrad: Leningradskaya lesotekhnicheskaya akademiya. 1(115): 97-106 (in Russian).
Tanskii, V.I. 1985. Application of economical harmfulness thresholds of most important pests of major agricultural crops. Methodical guidelines. Leningrad: VIZR, 28 p. (in Russian).
Tsinovskii, Ya.P. 1957. Biological bases for the forecasting of scarabeid beetles pupation In: Bei-Bienko, G.Ya., ed. Proc. 3 Congr. All-Soviet Entomol. Soc., Tbilisi. Moscow, Leningrad: IzdatelТstvo Akademii nauk SSSR, p. 38-39 (in Russian).
VasilТev, V.P., Livshits, I.Z. 1984. Fruit crop pests. Forest cockchafer (Melolontha hippocastani F.). Moscow: Kolos, p. 129-130 (in Russian).
Volkova, I.P. 1972. On inhabitation of Karelian nursery forests with forest cockchafer grubs. In: Shemeleva, A.V., ed. Proc. Sci. Conf. Karelian Biologists devoted to 50th anniversary of USSR. Petrozavodsk: Karel.skii filial AS USSR, p. 215-216 (in Russian).
Volkova, I.P. 1972. Features of settling of forest cockchafer (Melolontha hippocastani F.) on the territory of Karelia. In: Bei-Bienko, G.Ya., ed. Proc. 12 Internat. Etomol. Congr. V. 3. Leningrad: Nauka, p. 106 (in Russian).