Pests
Hoplocampa brevis Klug. - Pear Sawfly (Pear Fruit Sawfly)
Systematic position.
Class Insecta, order Hymenoptera, family Tenthredinidae, genus Hoplocampa Hartig.Biological group.
This is a pest of pears.Morphology and biology.
Body length of adult reaches 4-5 mm. Imago yellowish in color, dorsal side of thorax and abdomen darkened, mesonotum with black spots. Eyes rounded, vertex not towering above ocelli. Apical margin of clypeus is deeply emarginated. Pterostigma is yellowish. Ovipositor is slightly shorter than hind tibia. Larva is yellowish-white, head yellowish with brown spot on dorsal side. Larva molt 4 times. Body length of larva of last instar is about 10 mm. Larvae of last instar hibernate in cocoons in soil at a depth of 5-15 cm, rarely deeper. About 25% of larvae hibernate 2 years. Pupation occurs in spring during pear bud blossoming and at a temperature of about 7°C at a depth of 10 cm. Adults appear synchronously over 5-7 days during the balloon stage of pear. Parthenogenesis is typical of the species. Males appear sporadically in Pear Sawfly populations. Additional feeding on pollen and nectar of wild fruiters is obligatory for adults before propagation. Female scarifies epidermis of calyx and sepals with ovipositor and lays eggs one by one into fruit. Fertility is near 10-40 eggs. Egg develops in 6-7 days at air temperatures about 10-18°C. After hatching the larva mines fruit, after 1st molt it devours seeds and seed chambers. After every molt the larva changes fruit, causing injury to 4 fruits during its development. Larval development lasts 20-34 days. Most of larvae go underground for hibernation before abscission of injured fruits.Distribution.
The species inhabits Central and Northern Europe, Asia Minor and Iran. Perhaps introduced to North America. In the former USSR the species is distributed in Byelorussia, Moldavia, Ukraine, in middle and southern parts of the European part of Russia, and in the Caucasus.Ecology.
Adults of H. brevis appear in orchards earlier than other species of sawflies. Rosette of damaged fruit comprised of larval frass have specific smell.Economic significance.
Early-blossoming pear types are more strongly injured, especially in Armenia and Georgia. Autumn plowing and disking between tree rows are important preventive control measures against H. brevis. Control measures include pesticide treatment twice in the spring after mass appearance of adults during the red bud stage of development and immediately after blossoming.Reference citations:
Batiashvili I.D. 1959. Pests of continental and subtropical fruit crops. Tbilisi: Institut sel'skogo khozyaistva. 455 p. (In Russian)Ermolenko V.M. 1984. Family Tenthredinidae. In: Kopaneva L.M., ed. Keys to harmful and useful insects and mites on the fruiters and berry crops in the USSR. Leningrad: Kolos. 288 p. (In Russian)
Gusev V.G., Ermolenko V.M., Svishchuk V.V., Shmigovskii K.A. 1962. The atlas of insect pests of Ukraine. Kiev: Radyans'ka Shkola. 224 p. (In Ukrainian)
Mirzoyan S.A. 1970. Sawflies and horntails - the pests of bush and forest plantations of Armenia. Collection of works of Armenian Institute of Plant Protection. V. 1. Erevan: Armenian Institute of Plant Protection. 95-118 p. (In Russian)
Savkovskii P.P. 1976. Atlas of the pests of fruit and berry plants. Kiev: Urozhai. 207 p. (In Russian)
Tryapitsyn V.A., Zhelokhovtsev A.N. 1981. Order Hymenoptera, Suborder Symphyta. In: Narchuk E.P., Tryapitsyn V.A., eds. Insects and mites - pests of agricultural plants. V. 4. Hymenoptera and Diptera. Leningrad: Nauka. 221 p. (In Russian)
Vasil'ev V.P., ed. 1973. Pests of agricultural crops and forest plantations. V. 1. Kiev: Urozhai. 496 p. (In Russian)
Zhelokhovtsev A.N. 1988. Order Hymenoptera. Suborder Symphyta (Chalastogastra). Keys to insects of European part of the USSR. V. 3. Part 6. Leningrad: Nauka. 288 p. (In Russian)