Pests
Contarinia pyrivora Riley - Pear Midge, Pear Gall Midge
Systematic position.
Class Insecta, order Diptera, superfamily Sciaroidea, family Cecidomyiidae, subfamily Cecidomyiinae, genus Contarinia.Biological group.
Pest of pear.Morphology and biology.
Adult insect dark gray, body 3-4 mm, wing 2.5-3 mm long. Antenna long, yellowish-brown, 26-segmented in males, 14-segmented in females. Flagellum of imago with short pedicels. Adults differ from other species of the genus in having long pedicels on 11th and 12th flagellomeres. Larvae to 4 mm long, light yellow. Pupae winter in ground at a depth of 5-10 cm. Female lays 15-20 eggs in one bud by use of its long needle-shaped oviscapt, inserting them between opening flower parts. Sometimes 100 eggs appear in one bud, being laid by several females. Embryonal development lasts 4-6 days. As a rule, larvae hatch and go into receptacles before full blossoming. Larvae develop 30-40 days.Distribution.
The species is found in Europe (northward to Norway and Sweden), Japan, China, USA, Canada, Australia. In the former USSR, it is known in Latvia and Ukraine (Crimea). The species inhabits probably all territories of the European part of the CIS (except for the north).Ecology.
Monovoltine species. Imagoes fly in spring, in the phase of red buds of pear. After copulation, females start oviposition, which lasts until the beginning of blossoming. Larvae finish feeding in June, fall on the ground, and make cocoons. They remain in their cocoons until the end of August - the beginning of October, pupating in autumn and then wintering. Clinodiplosis pyricola Nordl. is a gall inquiline.Economic significance.
Larvae damage young fruits of pear, eating away apical part of ovary. The damaged fruits compared with healthy ones have a smaller size, covered with dark spots and slightly lengthened. Populated ovaries are distinguished by very fast growth. Due to abnormally large size, they are easily found on a tree in two weeks after flowering. By the end of larva development, the internal part of fruitlets are completely eaten. They dry up, shrink, dehisce, and fall down on the ground. Loss of fruits can reach 50-90% if there are no control measures. Agronomical control measures include soil loosening for destruction of larvae. Physical ones are trapping of imagoes by sticky traps during their flight. Chemical measures are insecticide treatments of pear trees in stage balloon.s status of pear growth.Reference citations:
Fedotova Z.A. & Kovalev O.V. 2001. Family Cecidomyiidae. In: Ler P.A., ed. Keys to insects of the Far East of the USSR. V. 6(2). Vladivostok: Dal.nauka, p. 390-614 (in Russian).Kryshtal. A.F. 1974. Cecidomyiidae. In: Vasil.ev V.P., ed. Pests of agricultural crops and forest plantations. V.2. Arthropods. Kiev: Urozhai, p. 499-519 (in Russian).
Mamaev B.M. 1969. Cecidomyiidae (Itonididae). In: Bei-Bienko G.Ya., ed. Keys to the insects of the European part of the USSR. V. 5(1). Moscow & Leningrad: Nauka, p. 356-420 (in Russian).
Mamaeva Kh.P. & Mamaev B.M. 1981. Cecidomyiidae. In: Narchuk E.P. & Tryapitsyn V.A., eds. Insects and mites . pests of agricultural plants. V. 4. Hymenoptera and Diptera. Leningrad: Nauka, p. 68-98 (in Russian).
Vasil.ev V.P. & Livshits I.Z. 1984. Pests of fruit crops. Moscow: Kolos, 399 p. (in Russian).