Plum Moth (Grapholitha Funebrana)

Pest Type: Fruit Pest

Row: Lepidoptera – Lepidoptera

Family: Leaflet Tortricidae

It is found everywhere. It damages plum, cherry plum, apricot, peach, thorns, occasionally sweet cherries and cherries.

Butterfly with a wingspan of 13-15 mm; fore wings dark brown with a faint violet tint; the mirror is blurry, with 3-4 black strokes or dots inside; hind wings monochromatic, gray-brown. The egg is round, 0.7 mm in size, flat, white, translucent, subsequently yellow-green. The caterpillar of the early centuries is pale white, adult, 12-15 mm long, pale pink; head and legs dark brown; prothoracic and anal shields light brown; abdominal legs with a two-tailed rim with 35-40 tightly located claws, anal legs with 18-22 claws. Pupa 7-8 mm in size, light brown; end of abdomen smoothly rounded, with eight hook-shaped setae at apex.

The caterpillars that completed feeding hibernate in spider web cocoons in cracks of the bark, under the lagged bark on the trunks, in the surface layer of the soil, in plant debris. Pupation begins 10-15 days after the daily average temperature goes beyond 10 ° C, which coincides with the period of bud isolation in late plum varieties. Pupation is extended and lasts 35-45 days. This extension further accompanies the subsequent stages of development. For the development of the pupa, 15-26 days are required. The flight of butterflies begins at the sum of effective temperatures + 105 … + 120 ° С (with a development threshold of 10 ° С), mass years – in 12-15 days. Butterflies are active after 17 hours and at dusk at an air temperature of at least 16-17 ° C. With a decrease in air temperature to 12-13 ° C years and egg-laying cease. The optimum temperature is 24-26 ° C. 3-5 days after departure, the female lays eggs one at a time, sometimes 2-3, on the illuminated areas of the fruit, less often on the lower surface of the leaves, most often the lower and middle tiers of the crown. Fertility – 50-90 eggs.

After 5-10 days, with the sum of effective temperatures of 190-200 ° C, caterpillars revive, which move from the surface of the fruit for several minutes to three hours. Upon penetration into the fetus, the caterpillar braids a small area with cobwebs and bites under the skin into it. After penetration, it closes the hole with cobwebs and stubs of the fetus. A drop of gum is released from the damaged areas.

After 3-5 days, the caterpillar makes a move in the pulp, reaches the cuttings and gnaws the bunch, as a result of which the flow of nutrients is disrupted, the growth of the fetus stops. Damaged fruits turn purple, prematurely “ripen” and fall off. In young fruits, the caterpillars damage the flesh and the uncured bone, while in mature ones the flesh gnaws around the bone, filling the cavity with excrement. Caterpillars can pass into another fruit. The development of the caterpillar lasts 20-30 days.

In the woodland and the northern forest-steppe, most of the caterpillars switch to cocooning and fall into diapause. In the southern regions, the second generation is developing.

However, even here a small part of the first generation caterpillars falls into diapause until the spring of next year. A significant loss of plum moth caterpillars, reaching in some years 70-80%, is observed in cold winters with little snow. The number of plum moths is reduced by arthropod parasites indicated for the apple moth, 5-10% of the pests are infected by entomophagy.

Protective measures. Carrying out a number of preventive measures indicated for the apple moth. Depending on the number of pests, one to two spraying of trees with insecticides against each generation. The first treatment is carried out at the beginning of the revival of the caterpillar caterpillars – when the sum of the effective temperatures of 190-200 ° C (threshold 10 ° C) is reached. As tests have shown, satisfactory results were achieved with the use of pheromone (fun on) to disorient males. Economic threshold of harmfulness: fishing for pheromone traps of five males for five days during the flowering of plums, 2-5% of damaged ovaries during their development and before harvesting.

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