Pest Type: Fruit Pests
Row: Hymenoptera – Hymenoptera
Family: true sawflies – Tenthredinidae
It is found everywhere. Significant damage is caused by pears in Transcarpathia, Crimea and the steppe zone of Russia.
Imago 4-5 mm long; yellow ore color with a slight blackening in the upper chest and abdomen; spots on transparent wings yellowish. The egg is 0.6 mm in size, whitish, shiny. Larva up to 10 mm long, yellow-white, yellowish chairman with bruympyatny top. Pupa – 6-7 mm, white, in a dense oval cocoon.
Larvae hibernate in a cocoon in the soil at a depth of 5-15 cm, individual individuals – up to 20-25 cm. Pupate when the soil is warmed up to 7 ° C at a depth of 10 cm, which coincides in time with the onset of pear bud swelling. Up to 20% of larvae that overwintered remain in diapause until next year. 11-14 days after the start of pupation, adults emerge – during the period of isolation of pear buds. Friendly years and lasts 15-17 days.
Males are rare, and therefore parthenogenesis is observed. From unfertilized eggs, females develop. For 4-6 days, females feed on nectar and pollen of stone fruit and wild pears that bloom early. The eggs are laid in incisions made with the help of an ovipositor in the perianth, receptacle tissue, at the base of the sepals, one per bud. Fertility – 30-40 eggs.
The ovaries of the female that has just emerged contain an average of 19 eggs. In connection with the gradual maturation of eggs, the duration of their laying is stretched to 10-14 days. Egg laying occurs strictly within the phenophases of separation and staining of pear buds. Therefore, it begins in the early and ends in the late varieties of pears. After 6-8 days, larvae are regenerated, which, without coming to the surface, gnaw through an annular passage – a mine at the base of the calyx, and after the first molt penetrate into the ovary of the fetus. In the seed chamber, the larva eats the seeds rudiments and the entire core, after which it carries out three more transitions from fetus to fetus. The larva develops 20-34 days, on average 26 days, passing five centuries over this period. Having finished feeding, the larva gnaws at the outlet and passes into the soil, where it remains until the spring of next year. Annual generation. Damaged fruits fall off.
The number of pear fruit sawfly is reduced by the same entomophages as the apple fruit sawfly.
The protective measures are the same as for the apple fruit sawfly.