Pests
Lyonetia clerkella Linnaeus - Apple Leaf Miner, Peach Leaf Miner
Systematic position.
Class Insecta, order Lepidoptera, superfamily Yponomeutoidaea family Lyonetiidae, subfamily Lyonetiinae, genus Lyonetia.Synonym.
Lyonetia aerella Тm.Biological group.
Pest of pome and stone-fruit rosaceous trees and bushes.Morphology and biology.
Small moth with narrow forewings of silvery-white to brownish-gray color (wingspan 8-10 mm). Anterior margin has 4 narrow black stripes just before apex. Wing apex with a fanlike black spot and narrow brush of dark hairs. Hind wings very narrow, with long fringe. Egg oval, matt-whitish. Caterpillar glass-green, with brown or black head and thoracic legs, 5 mm in length. Pupa light green to gray, within white cocoon. Moths winter under the peeled-off bark of trees and in other shelters. Female lays eggs one by one on the lower side of leaves, inside the leaf tissue, piercing underside epidermis. Average fertility is about 50 eggs with development in 5-7 days. Hatching caterpillar feeds upside down in a mine. Mine is very long, serpentine, slightly expanding, sometimes crossing the main vein, but not passing to another leaf. It is filled by light tissue of callus; the latter is formed by thin-walled cells lacking in chlorophyll and connecting the separated tissues of the leaf. Excrement in a mine is linearly situated, but the tip of the mine has no excrement. Having finished its feeding, the caterpillar gnaws a crescent outlet on the upper leaf side and goes outside. In Ukraine, the caterpillar feed duration is 6-14 days. Pupation occurs usually on the lower leaf side within white cocoons hanging on silk white threads. Pupae develop 11-21 days. Development of one generation lasts 27-39 days.Distribution.
Western Europe (except for northern Scandinavia), Asia Minor, Japan, Northern Africa, the Middle East, Madagascar, Korea, China (including Taiwan), Northern India. In the former USSR it is widespread in the European part (except for the North), in Transcaucasia, Kazakhstan, Central Asia, southern Siberia, in the Far East.Ecology.
The species develops in 3-4 generations in Ukraine, in 1-2 in the north. The beginning of the moth flight coincides with apple growth stage red bud in Ukraine; the flight starts in the last 3rd of April in Georgia and at temperature 11-12°C in Azerbaijan. The moths live 20 days. Oviposition coincides with appearance of first apple leaves (in Ukraine). Food plant change during a season is proven for the species. One leaf may bear several mines. Their maximal number, 1.5 mines per leaf on the average, is observed in the middle third of May, middle third of July, and also in August (in Georgia). One of the factors limiting population density is spring fluctuation of temperature. Wind is an essential factor for local migrations. The period of a generation development in autumn is longer than that in summer because of the increased duration of pupa stage. Moths of summer generations (in a zone of 3 generations) fly in June and August; wintering moths fly in October and April-May. The 2nd generation is the most harmful.Economic significance.
The pest is counted in a complex of leaf-mining moths in orchards of the south of the former USSR. The main damaged plants are plum, cherry and apple tree. Caterpillars mine also leaves of pear, quince, biwa, sweet cherry, hawthorn, mountain ash, cotoneaster, birch, hop, and willow. Gnawing through conduction tracts, the caterpillars break leaf metabolism and cause abscission of leaves. There is a linear correlation between mine density and quantity of leaves on shoots; the basal leaves of new shoots fall down more often than upper ones. Control measures. Agronomical ones are gathering and burning fallen leaves, clearing trunks and branches of drying bark. Biological measures are application of biologically active compounds (chitin synthesis inhibitors). Chemical ones are insecticide treatments of fruiters against young caterpillars before the mine length exceeds 1-2 cm. Replacement of insecticide treatments for biological ones is recommended.Reference citations:
Kholchenkov V.A. 1974. Family Lyonetiidae. In: Vasil.ev V.P., ed. Pests of agricultural crops and forest plantations. V.2. Arthropods. Kiev: Urozhai, p. 230-231 (in Russian).Kuznetsov V.I. & Seksyaeva S.V. 1994. Family Lyonetiidae (Leucopteridae, Leucopterigidae, Cemiostomidae). In: Kuznetsov V.I., ed. Insects and mites . pests of agricultural plants. V. 3(1). Lepidoptera. St.Petersburg: Nauka, p. 269-273 (in Russian).
Savkovskii P.P. 1976. Atlas of the pests of fruit and berry plants. Kiev: Urozhai. 207 p. (in Russian).