Pear Fruit Sawfly

2024 Author: Gavin MacAdam | [email protected]. Last modified: 2023-12-16 13:38

The pear fruit sawfly is especially harmful to pears growing in the steppe zone of Russia, as well as in the Crimea and Transcarpathia. As a rule, fruit trees are mainly harmed by larvae and, despite the fact that one-year generation is characteristic of malignant sawflies, they cause a lot of harm - the fruits attacked by them gradually fall off, which leads to a significant reduction in harvest volumes

Pear sawfly - description

The adults of pear fruit sawflies are 4 to 5 mm in size. These voracious parasites are characterized by a yellowish-ore color with a pronounced blackening in the upper abdomens and breasts. Small yellowish specks can be seen on the transparent wings of the pests.

Whitish shiny eggs of sawflies reach 0.6 mm in size. And the larvae growing up to 10 mm are painted in yellowish-whitish tones and are endowed with yellowish chairmen with brownish specks at the top. The size of the little white pupae, located in dense oval cocoons, ranges from 6 to 7 mm.

The wintering of harmful larvae takes place in the soil at a depth of five to fifteen centimeters - there the pests comfortably settle in their strong cocoons. And some individuals manage to go deep into the soil and twenty to twenty-five centimeters. As soon as the soil at a depth of ten centimeters warms up to seven degrees, pear fruit sawflies begin to pupate. As a rule, pear buds begin to swell at this time. About twenty percent of overwintered larvae continue to be in a state of diapause until the next season. In days eleven to fourteen after the start of pupation, when the pear buds begin to separate, adults begin to hatch. They are characterized by amicable years, lasting for fifteen to seventeen days.

Parthenogenesis is also characteristic of pear fruit sawflies, since males are extremely rare in the population. Females, developing from unfertilized eggs, feed on juicy nectar and weightless pollen of early flowering wild pears and some stone fruits for about four to six days. After a while, they begin to lay eggs, placing them in incisions in the tissues of the perianth, made with the help of the ovipositor. Also, females place eggs one at a time in the buds, near the bases of the sepals and in the tissues of the receptacle - there they also make characteristic cuts. The total fertility of each female averages from three to four dozen eggs. As a rule, the ovaries of newly released females contain about nineteen eggs. Due to the fact that the rest of the eggs ripen gradually, the egg-laying process of the sawflies stretches to one and a half to two weeks. At the same time, eggs are laid by pests exclusively at the stage of separation and coloring of pear buds. Because of this, the egg-laying process starts in early pear varieties and ends in later ones.

After six to eight days, tiny larvae are reborn. Without going outside, they immediately gnaw at the bases of the cups the ring-shaped passages-mines. And at the end of the first molt, the larvae make their way into the fruit ovaries. In the seed chambers, they eat out the entire core, together with the seed buds, and then pass from one fruit to another several times. The development of larvae takes from twenty to thirty-four days (on average - twenty-six), and during this time they manage to pass five centuries. Individuals who have finished eating gnaw out exit holes in the fruits and instantly move into the soil, where they stay until next spring.

Fighting the pear sawfly

In order to get rid of pear fruit sawflies as soon as possible, it is necessary to loosen the soil to a depth of nine to eleven centimeters. At the same time, it is necessary to loosen the soil layer not only in the near-trunk circles, but also in the nearby aisles. And repeated loosening with overturning of the previously treated layer contributes to the inevitable death of pests.

As for spraying with insecticides, it is advisable to carry out them during the mass summer of harmful sawflies.