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UDK:595.79.7.937+95
MAIN PESTS OF THE PEAR TREE AND THEIR BIOECOLOGY
Jumaev Rasul Akhmatovich
Professor, Tashkent State Agrarian University
Irgashova Nilufar
Associate Professor, Tashkent State Agrarian University
Orcid. 0000-0003-1340-8227
Abstract:
The article studies the main pests of the peach tree and their bioecology. The research
was mainly conducted between 2023 and 2024.
Pear lace bug (
Stephanitis pyri
F.) The adult pear lace bug is 3-3.5 mm long, with a dark brown
to black div. The forewings are reticulated (net-like), transparent like glass, with irregular dark
spots and prominent venation. The hindwings are reduced. The tip of the female’s abdomen is
rounded. The eggs are elongated, about 0.4 mm long, dark gray to black in color. Nymphs are
0.6-2.3 mm long, flattened, and light brown. From the third instar onward, wing pads begin to
develop.
Keywords:
Pear, biocenosis, pest, bioecology, infestation, distribution, generation, population.
Introduction:
In plant protection, the monitoring of fruit trees from the time seedlings are
planted until they begin bearing fruit must be conducted continuously throughout the year. Our
republic has highly favorable natural and climatic conditions for the development of horticulture.
However, the relatively long vegetation period, along with abundant heat and light, also
contribute to the rapid development of pests and diseases. Due to such favorable conditions,
pests and diseases cause significant damage to orchard productivity. Therefore, the effective
implementation of plant protection measures is of great importance.
Organizational and agronomic practices, as well as the selection of disease- and pest-resistant
fruit tree varieties, play a crucial role. Biological control methods, along with the selective use of
environmentally safer chemical agents, are also important.
The pear mite sometimes reproduces massively on pear leaves, severely damaging a significant
portion of the foliage and, to some extent, the fruits, weakening the overall condition of the trees.
As a result, the quantity of damaged fruits is substantially reduced sometimes by more than half.
Many of the young fruits fall prematurely. In heavily infested trees, both leaves and fruits may
fall off entirely well before ripening.
The gall-inducing pear mite (
Eriophyes pyri
Pagst) is extremely small and invisible to the
naked eye (without a microscope). The div of the mite is elongated, worm-like, with
transverse grooves on the abdomen and rows of small tubercles on the dorsal side. The
rostrum (snout) is short, and it has only two pairs of legs. Its size reaches up to 230 microns.
The presence of this pest on pear trees can be identified by characteristic changes occurring
on the tree.
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Figure
1. Leaves and fruits infested with pear mites
The pear mite
(Eriophyes pyri
Pagst) overwinters in sheltered areas near the base of pear
tree shoots, in front of buds, beneath bark layers and bud scales, and among fallen leaves.
In spring, the mites crawl onto newly emerging leaves and begin feeding on their sap. As a
result, galls (swellings) form slightly raised on the upper side of the leaf and flat on the
underside. These galls are hollow inside and connected to the outside air through small
openings on the inner side of the leaf. Initially, the galls are light green, but they later turn
dark brown or black. The pests feed and reproduce inside the galls. As the galls merge,
they form characteristic dark blotches. The pear mite produces several generations
throughout the summer.
The pear psylla (
Psylla vasilievi
Suts), both adults and nymphs, feed on the sap of pear
buds, leaves, flowers, and young shoots, causing the trees to become severely weakened.
Severely infested leaves blacken and fall off. If no control measures are taken, trees may
lose all their foliage as early as the beginning of July. The shoots of affected trees become
twisted and deformed; the fruits remain small, hard, tasteless, and are often covered with
sticky honeydew secreted by the pear psylla.
Figure 2. Shoots and leaves infested with pear aphids
Adult psylla reach up to 3 mm in length. Their div color ranges from yellowish to light
green-brown, with transverse black stripes on the abdomen. The wings are transparent,
with a dark spot at the rear edge; the hindwings are shorter than the forewings.
The adult female pear psylla (
Psylla vasilievi
Suts) is slightly larger than the male. Males
have two transverse dark stripes on the underside of their abdominal segments, whereas
females have two round dark spots. The tip of the female’s abdomen points downward, while
that of the male is slightly raised. Overwintering pear psylla are somewhat larger and darker
than summer generations.
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The eggs are tiny, white, and barely visible to the naked eye. Shortly before hatching, they
turn yellowish. One end of the egg is slightly enlarged and has a small stalk that helps it
adhere to twigs; the other end tapers into a bristle-like projection. The nymphs are wingless,
yellow (sometimes green), and flattened. In later instars, they become larger and develop
wing buds.
Pear psylla overwinter as adults under the bark scales on pear branches and partially on the
trunk. Shortly before bud break, they begin mating and laying eggs. Eggs are laid at the tips of
shoots and near the buds. The first generation feeds on the sap of swollen buds, newly
unfolded leaves, and especially flower calyxes. The pest develops rapidly, and by late April to
early May, new winged adults of the first generation appear. In Central Asia, pear psylla
produces 4-5 generations per season.
By the time the winged forms of the first generation emerge, the larger, darker overwintered
individuals die off. Summer-generation females begin laying eggs 3-8 days after emerging,
mainly along the veins on the upper surface of leaves. A single female can lay between 300
and 480 eggs during her lifetime.
An adult pear psylla lives approximately 2-3 months, so individuals from different
generations can be observed simultaneously throughout the summer.
Adult psylla frequently fly from one tree to another, whereas the nymphs are relatively
sedentary. Except for the first generation, nymphs from all subsequent generations excrete
abundant sticky, sugary honeydew, which is the basis for the pest’s common name. By the
end of summer, honeydew production becomes especially intense. This honeydew drips onto
leaves, shoots, the trunk, and fruits, causing contamination. Affected fruits develop light
brown sticky spots.
During summer and autumn, adult psylla continue to move between trees and aggregate in
large numbers to overwinter.
Pear sucker (
Psylla pyri
L.) The pear sucker and its nymphs feed on the sap of buds, leaves,
shoots, and fruits of pear trees. While feeding, they excrete a sticky, sugary substance known as
honeydew. As a result, vital physiological processes in the buds, leaves, and shoots are disrupted.
During periods of mass reproduction, the trees become sticky, the leaves turn black and fall
prematurely. The fruits harden, and the trees become weakened, which leads to a significant
reduction in yield the following year.
Adult pear suckers are reddish-brown with reddish eyes. The nymphs are yellow with transverse
stripes on their bodies. Overwintering individuals are dark gray in color.
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Figure 3. Leaf and stem infected with pear scab
The adult pear sucker (
Psylla pyri
L.) reaches a div length of about 3.7 mm. Its wings are small
and pale yellowish-white. Nymphs are yellow during the first and second instars, and greenish-
blue in the third instar.
The pear sucker is a monophagous pest that exclusively damages pear trees. It is widely
distributed across Central Asia. Adults overwinter in bark crevices of pear trees. Females
overwinter after mating and begin laying eggs on lower branches in early spring. After 5-7 days,
the nymphs hatch and begin feeding on young shoots, leaves, and flowers of the pear tree.
Within about a month, they develop into winged adults.
The pear sucker can produce up to five generations per season. A single female can lay up to 450
eggs, and adults live for up to two months. While feeding, nymphs secrete honeydew, which
promotes the development of fungal infections and other leaf diseases in many areas.
Pear lace bug (
Stephanitis pyri
F.) The adult pear lace bug is 3-3.5 mm long, with a dark brown
to black div. The forewings are reticulated (net-like), transparent like glass, with irregular dark
spots and prominent venation. The hindwings are reduced. The tip of the female’s abdomen is
rounded. The eggs are elongated, about 0.4 mm long, dark gray to black in color. Nymphs are
0.6-2.3 mm long, flattened, and light brown. From the third instar onward, wing pads begin to
develop.
Adults overwinter under fallen leaves, bark crevices, and other protected locations. They become
active in early April and migrate to the trees. At the end of the pear flowering period, females
begin oviposition, inserting 7-8 eggs per site into the underside of leaves. A female may lay up to
400 eggs. Eggs hatch in 20-30 days, and nymphs reach adulthood in 25-30 days.
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Figure 4. The appearance and damage of pear kandal
Both adult and nymph stages of the pear lace bug (
Stephanitis pyri
F.) feed on the underside of
pear leaves by sucking plant sap. Severely affected leaves lose their coloration, and the underside
becomes stained with excrement, leaving dark spots. The first generation of adults emerges in
June, reproduces immediately, and starts laying eggs. The second generation, which is more
numerous and causes greater damage, appears in August and enters diapause for overwintering.
This pest produces two generations per year.
Case-bearing moth (
Coleophora hemerobiola
Fil.) The larvae of this species feed on the swelling
and newly opening buds of quince, cherry plum, cherry, pear, and especially apple trees, leading
to significant defoliation in early spring. As a result, the trees remain without foliage for an
extended period. Later, the larvae feed on the leaf petioles and lamina. Severely damaged leaves
turn brown and appear scorched.
The adult moth has a wingspan of approximately 12 mm, with a div length of around 5 mm.
The wings are narrow and pointed at the tips. The forewings are grayish with darker tips, while
the hindwings are a lighter shade of gray. Both fore- and especially hindwings bear long fringes
composed of elongated scales.
Figure 5. Sheath moth, caterpillar appearance and damage
The case-bearing moth (
Coleophora hemerobiola
Fil.) The mature larva reaches up to 5 mm
in length and is liver-colored, with two forked projections at the posterior end of the
abdomen. The larva lives inside an elongated, light brown case. The anterior end of the case
is trumpet-shaped and attaches to the tree bark via this widened part. A silk thread emerges
from the trumpet-like opening. The posterior end of the case is shaped like a three-sided
pyramid, with a radial slit in the tip.
Before pupation, the larva reaches a length of 5-6 mm and is light brown with a darker head.
The dorsal sides of the first and second thoracic segments feature a pair of forked black
shields. The larva resides inside the case, which enlarges as the larva grows. The species
derives its name from this behavior. When the larva moves, it drags the case along and
protrudes the anterior part of its div from the trumpet-shaped opening.
The larval case is distinguishable from the pupal case by its slightly flattened shape and lack
of a pyramidal end. The egg is short, oval-shaped, approximately 1–3 mm long, with one end
blunt.
Larvae overwinter in the mid-instar stage on branches of host fruit trees and awaken in early
spring before bud swelling. By the time black locust (Robinia pseudoacacia) begins to bloom,
the larvae cease feeding and descend to the tree trunks, hiding under bark scales or in bark
crevices. They attach themselves using silk, seal the front of the case, bend their heads
toward the posterior end, and remain motionless. After some time, pupation occurs.
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About one month later, adult moths emerge. In late May or June, females lay 50–70 eggs on
the underside of leaves, mainly along the midrib. Nine to ten days later, larvae hatch,
penetrate the leaf mesophyll between the upper and lower epidermis, and feed internally.
Afterward, they exit and construct a case on the leaf surface. There, they continue feeding
throughout summer, creating nearly circular cavities.
The larva attaches itself to the leaf via the trumpet-like end of the case, extends part of its
div into the leaf, feeds, and then re-enters the case to relocate. Growth is slow, and by
September-October, feeding ceases. Larvae overwinter on the same twigs.
The blotch leafminer moth (
Cemiostoma scitella
Zell.) This moth mines the leaves of apple
trees and, occasionally, pear trees, forming rounded blotches. In cases of heavy infestation,
the damaged areas merge, occupying a large portion of the leaf blade. Adults have a
wingspan of 5-8 mm. The wings are silvery-white with a shiny, pale bluish hue, and the tips
of the wings are marked with small dark spots.
Figure 6. Spiny moth, appearance and damage of the worm
The blotch leafminer moth (
Cemiostoma scitella
Zell.) The egg is oval-shaped and white.
The larva reaches up to 5 mm in length, is pale yellowish-white, and has a liver-colored
head. The larvae develop legs only after the fourth instar. The pupa is dark yellow and
resides inside a white, rhomboid-shaped cocoon. The blotch leafminer overwinters in the
pupal stage beneath soil particles around the tree, among dry fallen leaves, and partially in
bark crevices.
In the first half of April, adult moths emerge from the pupae. Female moths lay single eggs
on the lower side of apple and sometimes pear leaves. During its lifespan, a female lays 40-
80 eggs. The most favorable temperature for the moth’s activity is 23-24°C. Larvae hatch 8-
12 days after oviposition.
The larvae feed on the mesophyll of the leaf, creating rounded blotches. By early May,
numerous blotches appear on leaves, which continue to increase gradually throughout the
summer. Larval development takes about two weeks, after which the larvae emerge onto the
leaf surface and pupate in place without descending. The pupal stage lasts 9-16 days. In
summer, C. scitella completes a generation in just over a month. The species produces four
generations per year. The larvae of the final generation spin a silk thread and descend to the
ground to pupate. In Central Asia, natural enemies particularly parasitoids developing in the
larval and pupal stages suppress population outbreaks of the blotch leafminer. However, the
species composition of these parasitoids is not yet fully identified.
REFERENCES
1.
Jumaev RA, Kimsanboev XX, Adilov MM, Rustamov AA, The technology of rearing
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Braconidae in vitro in biolaboratory,
European Science Review
3-4, 3-5 (2017).
2.
Rasul Jumaev. Methods of determining the optimal temperature and humidity in
dryness and storage of in vitro propagated parasitic entomophages. E3S Web of Conferences.
2024. –P. 553.
3.
Rasul Jumaev, Abdurakhim Kuchboev, Nozimakhon Jumaeva, Farukh Yakubov,
Shamsi Esanbaev. Molecular identification and polymerase chain reaction analysis of
Xanthogaleruca Luteola (Chrysomelidae) species. E3S Web of Conferences. 2024. –P. 563.
4.
Jumaev R, Invitro rearing of parasitoids,
E3S Web of Conferences
371, 01032 (2023).
5.
Lebedeva N, Akhmedova Z, Kholmatov B, Revision of stoneflies insecta: plecoptera
fauna in Uzbekistan,
E3S Web of Conferences
258, 08030 (2021).
6.
Gazibekov A, Sulaymonov O, Sobirov B, Representatives of Lepidoptera groups
occurred in forestry and agricultural crops and their effective entomophage types,
E3S Web of
Conferences
244, 02020 (2021).
7.
Kimsanboev K, Rustamov A, Usmonov M, Euzophera Punicaella Mooze Lepidoptera
bioecology and development of host entomophagic equilibrium in biocenosis,
E3S Web of
Conferences
244, 01003 (2021).
8.
Kimsanbaev K, In vitro mass reproduction of parasitic entomophages Braconidae
Trichogrammatidae,
E3S Web of Conferences
389, 03100 (2023).
9.
Axmatovich JR, In vitro rearing of trichogramma Hymenoptera: Trichogrammatidae,
European science review
9-10, 11-13 (2016).
10.
Axmatovich JR, Karimbaevich SS, Qizi NB, O'g'li BSS, Bioecology of generations of
Trichogramma diluted by different methods,
European science review
3-4, 25-28 (2018).
11.
Rustamovich SI, Xamrakulovich KX, Axmatovich RA, Nozimxon J, Axmatovich JR,
Bioecology harm of tobacco trips for the cotton plant and measure of counteraction,
European
science review
3-4, 29-31 (2018).
12.
Dаlabaevna MR, Shavqievich MK, Axmatovich JR, The development of russet mite in
various plants and effectiveness of pesticide,
European science review
1-2, 21-23 (2018).
13.
Abdushukirovich SB, Xamraqulovich KX, Axmatovich JR, Karimbaevich SS, Rearing
of Trichogramma species T evanescens T pintoi T chilonis in vitro culture,
European science
review
1-2, 29-31 (2018).
14.
Shamsi Esanbaev, Rasul Jumaev. Study on stem pests of elm tree in Uzbekistan. S
Esanbaev, R Jumaev - E3S Web of Conferences, 2024.
