Інвазійні комахи-шкідники інтродукованих рослин дендрологічного парку “Олександрія” НАН України. Повідомлення 3: щодо біології Pineus orientalis (Dreyfus, 1889) (Heteroptera: Adelgidae)
The article discusses problems associated with the introduction of plants and the accompanying invasion of new species of insect pests into park plantings. It emphasises the urgent need to study their biology. The paper describes some biological features of one of the invasive species of pests – the...
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| Дата: | 2026 |
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M.M. Gryshko National Botanical Garden of the NAS of Ukraine
2026
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Plant Introduction| _version_ | 1860145181975642112 |
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| author | Dragan, Grygoriy |
| author_facet | Dragan, Grygoriy |
| author_sort | Dragan, Grygoriy |
| baseUrl_str | https://www.plantintroduction.org/index.php/pi/oai |
| collection | OJS |
| datestamp_date | 2026-01-09T02:00:58Z |
| description | The article discusses problems associated with the introduction of plants and the accompanying invasion of new species of insect pests into park plantings. It emphasises the urgent need to study their biology. The paper describes some biological features of one of the invasive species of pests – the Eastern pine adelgid, Pineus orientalis. The data on phenology, feeding and reproductive features, number of generations, composition of life cycle morphs, and damage caused by P. orientalis to its forage plants are presented. |
| doi_str_mv | 10.46341/PI2025015 |
| first_indexed | 2026-02-08T08:11:58Z |
| format | Article |
| fulltext |
© The Authors. This content is provided under CC BY 4.0 license.
Plant Introduction, 109, 3–13 (2026) ISSN 1605-6574, e-ISSN 2663-290X
RESEARCH ARTICLE
Invasive insect pests of introduced plants of the “Оlexandria” Dendrological
Park. Report 3: towards a biology of Pineus orientalis (Dreyfus, 1889)
(Heteroptera: Adelgidae)
Grygoriy Dragan
The “Оlexandria” State Dendrological Park of the National Academy of Science of Ukraine, Ukraine, Kyiv region, 09113 Bila Tserkva,
Ukraine; adragangid@gmail.com
Received: 20.09.2025 | Accepted: 04.11.2025 | Published: 08.01.2026
Abstract
The article discusses problems associated with the introduction of plants and the accompanying invasion
of new species of insect pests into park plantings. It emphasises the urgent need to study their biology.
The paper describes some biological features of one of the invasive species of pests – the Eastern pine
adelgid, Pineus orientalis. The data on phenology, feeding and reproductive features, number of generations,
composition of life cycle morphs, and damage caused by P. orientalis to its forage plants are presented.
Keywords: Pineus orientalis, plant introduction, biological invasions, full development cycle, side development cycle, diapause, life
cycle morphs
https://doi.org/10.46341/PI2025015
UDC 595.752.2
Funding: The research was conducted under the thematics 0123U100482 “Natural and anthropogenic transformation and problems
of preservation of local and introduced flora of the dendrological park “Olexandria” of the NAS of Ukraine” (budget program code
6541030).
Competing Interests: The author declares no conflict of interest.
Introduction
The study of pests and diseases of introduced
plants is integral part of scientific research
aimed at solving, among other things, such
problems as, assessing the pressure of the
new biotic environment on the introduced
plant, the impact of introductions on local
ecosystems due to the introduction of new
pests and pathogens, a detailed study of the
biology of invading pests, organization of
the monitoring and ways to manage their
numbers. All the issues are related to a more
general problem – the problem of biological
invasions. Currently, this topic has become
a central theme in modern ecological and
environmental research (Ehrenfeld, 2010;
Strayer, 2012; Carneiro et al., 2024).
Biological invasions are one of the main
components of today’s global changes.
Through mechanisms such as predation,
hybridization, or competition, invasive species
offer unique opportunities to understand
fundamental evolutionary and ecological
processes, thanks to their ability to adapt to
new environments and successfully compete
with native species (Haubrock et al., 2023).
The “Оlexandria” State Dendrological Park
of the National Academy of Science of Ukraine
(Dendropark “Olexandria”), located in the Kyiv
region (Ukraine), has also faced the problem
of biological invasions. The natural conditions
https://creativecommons.org/licenses/by/4.0/
https://orcid.org/0009-0000-2697-0783
4 Plant Introduction • 109
Dragan
and terrain of the park are conducive to the
growth and development of a diverse range
of vegetation. Nearly 1,200 species and forms
of tree species from various floristic zones
worldwide grow in the park (Boyko et al., 2013).
One of the consequences of the large-scale
introduction of plants into the park was the
invasion of new species of tree-eating insects
into its plantings. Over the past twenty years,
the park’s entomofauna has been enriched by
at least 20 species of insect invaders (Dragan
& Dragan, 2024), and this list continues to
grow. In 2025 alone, about 36 such species
have already been identified. Park ecosystems
saturated with introduced plants have proven
to be highly favorable for the establishment
of invasions and the formation of stable
populations. An example of successful insect
invasions in park plantings is the plane tree
leaf miner (Phyllonorycter platani Staudinger,
1870), which has been severely damaging a
group of plane trees in the Great Meadow
landscape area for several years, or the
Japanese lime leaf miner (Phyllonorycter issikii
Kumata, 1963), which has been found en masse
on many species of Tilia spp. Another invasive
species, the oak lace bug (Corythucha arcuata
Say, 1832), also poses a great danger to park
plantings. Currently, it damages introduced
oak species, such as Quercus macranthera
Fisch. & C.A.Mey ex Hohen, Q. castaneifolia
C.A.Mey, Q. serrata Murray. However,
C. arcuata causes the most damage to the local
species – Q. robur L.
A special place among new invasive pests
belongs to a group of insects from the family
Adelgidae (Heteroptera). This family comprises
approximately 70 species known today, which
are distributed worldwide (Favret et al., 2015;
Havill et al., 2025). Among them are many
serious forest pests (Havill & Foottit, 2007).
These include, in particular, the eastern pine
adelgid, Pineus orientalis (Dreyfus, 1889),
which comes from Western Caucasus and
Anatolia (Turkey). In this area, its primary host,
the Eastern spruce (Picea orientalis (L.) Link),
and local pine species (secondary host plants)
naturally grow. In Europe, Pineus orientalis is
widespread almost everywhere in parks where
its forage plants are found (Steffan, 1972; Liska
et al., 2011; Albrecht, 2017).
In Ukraine, it can be found in the parks of
the Forest-Steppe and Chernihiv Polissya, as
well as botanical gardens of all natural zones
(Dmitriev, 1987; Dragan, 2013; Pokhilchenko
et al., 2020).
Adelgids (Heteroptera, Adelgidae) have
very complex life cycles. Famous researcher
of this group of insects, Eichhorn (1989),
noted that the development cycles of adelgids
belong to the most fascinating phenomena in
biology, and their progressive understanding
is one of the remarkable achievements of
entomologists. Despite a long history of
studying their life cycles, many questions
concerning the general biology of adelgids,
as well as the specific biology of individual
species, remain insufficiently studied. One
such species is the Eastern pine adelgid
(Pineus orientalis), the biology of which has
been studied for over 130 years.
According to Kholodkovsky (1915), the
species was first described by Dreyfus in
1888 on Eastern spruce, where it produced
long spindle-shaped galls. Marshal (1913)
considered this species to be the eastern
race of the European Pineus pini Macq.
Kholodkovsky (1915) suggested that Pineus pini
and P. orientalis were originally one indigenous
southern species, which then split into two:
one southern (Chermes (= Pineus) orientalis
sensu stricto) and one northern (Ch. pini),
which lost the ability to form galls and retained
migration only as a biological rudiment.
According to modern studies employing the
molecular methods (DNA barcoding), the
Pineus pini / P. orientalis species complex
is essentially a single species (Havelka et al.,
2019).
Steffan (1972) classified this adelgid as a
typical holocyclic species with five generations
(fundatrix, alata migrans, hiemosistens,
sexupara = andropara + gynopara, and
sexualis), the order of which is genetically
determined (Fig. 1).
Some recent authors also describe the five-
generation complete life cycle of adelgids as
typical (Havill & Foottit, 2007; Sano & Ozaki,
2012).
Lampel (1968), considering adelgids in
general, also pointed out that their complete
life cycle consists of five stages. In this case,
each morph within the main cycle is usually
represented by one generation, and before
sexupara, there is only one generation of
settlers. However, referring to the works of
other authors (Böerner & Heinze, 1957), he
considered the Eastern pine adelgid to be
Plant Introduction • 109 5
Invasive insect pests of introduced plants of the “Оlexandria” Dendrological Park. Report 3
an exception, since this species has two or
three generations of settlers before sexupara.
Later, Liska et al. (2011) proposed a schema
for the development of Pineus orientalis that
was significantly different from the others.
This schema included winged form of the
settlers (i.e., alata exsulans, according to the
generally accepted terminology for adelgids)
as well as several generations of sistentes
(Liska et al., 2011). The existence of the Pinus
orientalis morph sistens in the life cycle is
also mentioned in other sources (Dransfield &
Brightwell, 2025).
According to the concept of double cycles
(Steffan, 1968, 1972), the life cycle of the
Eastern pine adelgid consists of two parallel
phases, male and female, which interact
only during the sexual reproduction of the
amphigonous generation. At the same time, a
secondary developmental cycle (paracycle) is
assumed only in the female line. Consequently,
with the temporary loss of the primary host,
the adelgid population loses the potential
opportunity to restore the holocycle due to
the loss of the ability to produce androparous
and male forms. It should be noted that this
concept was later emphasized (Eichhorn, 1989;
Alles, 1994), and the limits of its applicability to
the entire group of adelgids remain unknown.
Figure 1. Diagram of the life cycle of the Eastern
pine adelgid (Pineus orientalis Dreyfus, 1889)
adapted from Steffan (1972). Designations:
F – fundatrix; Am – alata migrans; H – hiemosistens;
P – progrediens; A – andropara; G – gynopara;
Sm – males; Sf – normal females.
Several other issues important for
understanding its biology also remain unclear.
Meanwhile, to the best of our knowledge,
there is very little research on this issue. This
article presents the results of studies that
complement and clarify the existing knowledge
about the life cycle of Pineus orientalis.
Material and methods
All stationary observations and experiments
were carried out in the Dendropark
“Olexandria” in 1998–2024. Seedlings of
pine (Pinus sylvestris L.) in containers
were used to study the peculiarities of the
seasonal development of Pineus orientalis.
All experimental pine plants were free from
settlement by any phytophagous insects that
could affect the course and results of the
research.
Non-opened pine adelgid galls were
transferred to experimental pine seedlings.
The nymphs emerging from galls molted into
adult winged females. These females moved
to the needles of pine trees and began to lay
eggs there. Larvae hatched from the eggs,
which fed on the bark of shoots and developed
there into imagoes. The egg clutches of these
adults were transferred to uninfected plants.
This procedure was then repeated until the
end of the season. The last generation of the
year did not develop into imagoes and instead
entered winter diapause in the larval phase at
various ages. Three years after the experiment
began, the experimental pine plants with
adelgid colonies were transferred to a site
where Eastern spruce trees (Picea orientalis)
had been growing for many years. During the
entire previous period, no damage (galls) by
any species of adelgids was ever recorded
on them. Since this procedure was carried
out in early spring, the appearance of winged
sexupara flying from experimental plants was
observed on the Eastern spruce in the same
year, and galls of a typical form were observed
the following year.
The preparation of microslides was carried
out according to the generally accepted
method in aphidology (washing in alcohol,
maceration of soft tissues in a KOH solution,
mounting in Fora liquid). Photos were taken
using the built-in camera on the Oppo Reno
8 T smartphone.
6 Plant Introduction • 109
Dragan
Results
According to the results obtained, the seasonal
development of Pineus orientalis is as follows.
On the Eastern spruce, the first-age fundatrix
larvae (Fig. 2) overwinter, attached to the bases
of the needles on the shoots of the last year of
life.
The spring reactivation of overwintering
larvae was observed in different years
depending on weather conditions from
the end of March to the second decade of
April. After three molts, they turn into adult
parthenogenetic females, which reproduce
within a few weeks, laying up to 200 eggs
(Fig. 3).
The alata migrans larvae hatching from
them move to the bases of the needles on the
green shoots of the current year. Under the
influence of their sucking, the bases of the
needles, and often the adjacent part of the
stem, swell, forming chambers in which the
larvae feed and develop into nymphs (larvae of
the last fourth instar). The galls of the Eastern
pine adelgid (Fig. 4) are pretty diverse in
shape. Most often, these are spindle-shaped
neoplasms of various but sometimes slightly
shortened and curved shoots, in which all or
almost all needles swell at the base. The shape
of the galls is apparently determined by the
state of the shoots at the beginning of their
settlement by the phytophagic larvae. Spruce
shoots at an early stage of their development
are more sensitive to the effects of growth-
active substances released by the larvae
during sucking. Hence, the more profound
transformations of the shoot. In other
cases, when the shoot completes its normal
development, the invasion of the larvae only
slightly transforms it.
The opening of the galls of Pineus orientalis
was observed in some years as early as the end
of May, but in other years, it occurred during
June. Migration to pine begins, as a rule, in
the second decade of June and ends by the 1st
decade of July. Migrants lay up to 25–30 eggs
on pine needles. After 10–15 days, larvae hatch
from them, which feed on the bark of shoots
of different ages or very rarely on needles.
During heavy precipitation, the latter are most
often washed away by rain.
Аfter four molts, these larvae mature into
parthenogenetic egg-laying females, giving
rise to three or four generations of settlers.
It should be emphasized that all individuals
of settlers, developing on a secondary host,
without exception, reach maturity after
passing four larval instars.
Morphologically, individuals developing on
pine throughout the season are very similar,
although there are some differences of a
purely quantitative nature. The differences
Figure 2. First instar larval skin of Pineus orientalis.
× 200.
Figure 3. Adult fundatrices – white waxy lumps at
the base of spruce (Picea orientalis) needles.
Plant Introduction • 109 7
Invasive insect pests of introduced plants of the “Оlexandria” Dendrological Park. Report 3
Figure 4. Pineus orientalis on Picea orientalis shoots: A – galls on young shoots; B – damage to shoots
remaining after galls dry up.
BA
concern the size of the body, the degree of its
sclerotization, and the number of wax glands
(Fig. 5).
External factors determine the transition
to winter diapause, with the most significant
ones being the reduction of photoperiod,
the condition of the food plant, and a
decrease in temperature. In warm, humid,
and prolonged autumn seasons, the onset
of diapause in settlers shifts from the
usual end of September to the beginning of
October, and then to the end of October,
to the start of November. Larvae of all four
ages overwinter on pine, but mainly larvae
of older ages, and, as a rule, the last two
generations of the year.
The spring resumption of the development
of overwintered larvae is closely related to
the beginning of vegetation (bud swelling)
in pine. The first reactivated larvae can be
observed, depending on weather conditions,
from the second half of March to the second
decade of April. Transformation into adult
parthenogenetic females occurs after a total
of four molts. Individuals that overwintered
in older larval instars in the imago phase
have larger sizes, a greater degree of
sclerotization, and waxy pubescence of the
body than individuals that went into winter
diapause as larvae of the first or second
instar.
The mass maturation of the overwintering
generation typically occurs at the end of April.
Still, in years with an early and warm spring,
it may occur at the beginning of this month.
Females lay eggs, 70–110 in total, over two and
a half to four weeks. From these, larvae of the
next (first summer) generation emerge, which
primarily move to May shoots of pine. However,
some of them populate the bases of needles
under the film covering, the bark of shoots
from previous years of life, thick branches, and
even the trunks of young pine plants. After a
little less than a month, they turn into either
wingless or winged adult females.
Wingless females of the first summer
generation give rise to several more
generations of the same individuals. In total,
up to six summer generations of settlers can
develop on a pine within the paracycle during
the season.
The appearance of the winged females
(sexupara) varies slightly by year. Thus, over
a long-term observation period, we noted a
difference of only a few days (May 18–22). In
nature, the winged females always develop
only on young May shoots. In experimental
conditions (complete removal of growth buds
8 Plant Introduction • 109
Dragan
in spring), they also occurred on needles.
No other winged forms develop on the pine
except for the sexupara. The report of alata
exsulantes in the life cycle of Pineus orientalis
(Liska et al., 2011) has not been confirmed in
our research.
As our studies have shown, sexupara Pineus
orientalis remigrate to the primary host with
immature sexual products and therefore need
additional nutrition. As a result, they lay eggs
for one to two weeks. In this case, a relatively
small number of eggs are laid – up to 20 pcs.
As a result of the sexupara sucking on the
spruce needles, the latter turns yellow and
is slightly deformed. When feeding, females
produce abundant waxy pubescence (Fig. 6).
Under the protection of this pubescence and
the wings of the female itself, the development
of the next generation occurs – sexual females
and males. In this case, the sexupara –
gynopara and andropara, produce individuals
of one sexual type – either females or males.
The maturation of individuals in the sexual
generation – specifically, normal females and
males – occurs during July and early August.
As a result, copulation and laying of fertilized
eggs by normal females is also stretched out
in time. After fertilization, females climb into
various secluded places, often these are the
remains of scales between annual growths,
where they lay only one egg. From them,
fundatrix develops during July – mid-August.
This marks the end of the full two-year
development cycle of the Eastern pine adelgid.
An important area of our research was the
study of the peculiarities of the Eastern pine
adelgid life cycle under conditions of isolation
from its primary host and after restoration
of this connection. Studies have shown that
under isolation conditions, the development
of adelgids on pine has not undergone any
changes in the number of generations or in
the composition of morphs. What is important
to note is that every year, the adelgid colonies
on the experimental plants produced winged
individuals in the spring. After reconnection
of communication with the primary host,
the same year, the sexuparas were observed
to remigrate to spruce and subsequently
develop normal females and males, followed
by fundatrices. The following year, galls
typical of the eastern adelgid developed on
the spruce. Thus, this experiment showed
that the complete development cycle of this
species can be restored from a paracycle that
functioned for some time in isolation from it.
Discussion
The data we obtained show that the complete
life cycle of the Eastern pine adelgid differs
from the ‘classical’ scheme, which typically
involves five generations. In total, the complete
BA
Figure 5. Pineus orientalis: A – adult hiemoprogrediens; B – adult aestivoprogrediens. × 80.
Plant Introduction • 109 9
Invasive insect pests of introduced plants of the “Оlexandria” Dendrological Park. Report 3
Figure 6. Pineus orientalis on Picea orientalis shoots: A – galls and sexupara on the shoot tips; B – sexupara
and damaged (dechromated) spruce needles.
BA
two-year life cycle of this species consists
of nine to ten complete generations (Fig. 7).
Within the paracycle, up to six complete
generations of settlers can develop on the
pine tree. It can be said that the number of
generations within both the holocycle and
paracycle of the Eastern pine adelgid is not
fixed. The data obtained generally confirm the
results of Böerner & Heinze (1957), specifying,
however, that after migration to the pine
tree, this species can develop twice as many
generations of settlers before the appearance
of sexupara as these researchers indicated.
There is a widespread opinion that adelgids
undergo a typical five-generation complete
life cycle (Lampel, 1968; Steffan, 1972; Havill &
Foottit, 2007; Sano & Ozaki, 2012). Only a few
cases of deviation from this rule were reported
(Lampel, 1968). However, holocycle comprising
more than five generations occurs in Dreyfusia
prelli, D. merkeri, Adelges laricis (Eichhorn,
1957, 1994), Pineus orientalis (Böerner & Heinze,
1957), Dreyfusia nordmannianae, Aphrastasia
pectinataе (Dragan, 1996, 1999), and possibly
in Gilletteella cooleyi (Dragan, 2012). Therefore,
we do not share the opinion that a five-
generation full life cycle is typical for adelgids,
as suggested by some authors (Steffan, 1972;
Havill & Foottit, 2007; Sano & Ozaki, 2012). On
the contrary, the data we have indicate that
the five-membered holocycle of adelgid is
most likely an exception with a limiting case
of reduction in the number of generations in
the holocycle. According to our data, a similar
holocycle is present in Sacchiphantes viridis
Ratz. and, possibly, in some other species of
adelgid.
As the present studies have shown, in the
Eastern pine adelgid, the development of the
population on the secondary host within the
holocycle proceeds synchronously with the
paracyclic one. It should be assumed that such
a feature is also characteristic of other adelgid
species. Knowing how the adelgid population
develops in the secondary cycle, it is possible
to predict that the part of the population that
is involved in the full development cycle will
behave similarly on the secondary host.
Regarding the morphs of the Eastern pine
adelgid’s life cycle, in addition to the three on
the primary host, there are only two on the
secondary host: progrediens and sexupara
(also known as andropara/gynopara).
The morph sistens, the presence of which
was previously reported by other sources, is
absent from the life cycle of this species. Let
us clarify our position on this issue. The term
‘sistens’, denoting individuals developing
10 Plant Introduction • 109
Dragan
on the secondary host with a period of
rest, was introduced by Marshall (1913), and
cited by Lampel (1968). Among them, he
distinguished sistens, which develop with a
break for summer diapause – aestivosistens-
and those for winter – hiemosistens. He
gave the name ‘progrediens’ to individuals
developing on the secondary host without
diapause. Steffan (1968) held similar views.
He believed that the progrediens morph is
unspecialized and has four larval instars,
while in fundatrix, hiemosistens, and
aestivosistens, the number of instars was
reduced to three during evolution. In the
diagram of the life cycle of Pineus orientalis
proposed by Steffan (1968, 1972), it is clearly
seen that in this species, it is precisely the
specialized form hiemosistens that develops
on the secondary host in three instars. At the
same time, Steffan (1972) noted that fourth
instar larvae can also overwinter on the
secondary host, which, in connection with
this, cannot be classified as hiemosistens.
This contradiction does not allow us to
state with certainty what views the author
adhered to regarding the existence of a
specialized winter-diapausing morph in the
Eastern pine adelgid.
Figure 7. Diagram of the life cycle of the Pineus
orientalis by G. Dragan (first published here).
Designations: F – fundatrix; Am –alata migrans;
Ex1–6 – generations of settlers (exules, progrediens);
hiem Ex – hiemoprogredientes; Sp – sexupara
(andropara + gynopara); Sx – sexualis (males and
normal females).
In turn, Lampel (1968) divided the individuals
developing in summer on a secondary host
(aestivales) into aestivoprogrediens and
aestivosistens. As can be seen from the names,
the former develop without diapause and
the latter with diapause. He assumed that
progrediens are always only aestivales, i.e.,
individuals that develop into adults in summer.
He classified all hibernating individuals as
hiemosistens (= hiemalis).
In our opinion, the assignment of wingless
settlers to one or another morph should
be based on biological basis rather than on
seasonality. These biological characters,
which allow differentiating the wingless
settlers into morphs, are the number of larval
instars and the presence of an obligatory
diapause in the first larval instar. The latter
factor is independent of external conditions
and is genetically determined. All settlers of
Pineus orientalis that winter on pine, without
exception, develop into adults after four larval
instars, and none of them exhibit obligatory
diapause in the first larval instar. As already
mentioned, their diapause is determined by
external conditions, and they go to hibernation
in one to four instars.
Thus, the Eastern pine adelgid generally
lacks the hiemosistens morph and sistens
morph in its life cycle. In fact, in this
species, the non-specialized progrediens is
the hibernating morph. Individuals of this
morph develop without diapause in the
summer season. However, with the onset of
the unfavorable winter season, they enter
diapause at a certain age, when the effect of
external factors that eventually cause diapause
reaches a critical value. We will distinguish
two seasonal variations of the morphs
progrediens – aestivo- and hiemoprogrediens
in the eastern pine adelgid. Then, all breeding
individuals of the settlers in the summer period
should be referred to as aestivoprogrediens,
and those breeding after winter diapause –
to hiemoprogrediens. A similar approach to
distinguishing between summer and winter
settlers on pine was applied earlier by Annand
(1928). It is the external conditions (lower
temperature, shorter daylight hours) affecting
the development of larvae for a sufficient
amount of time in the period preceding
diapause that cause the corresponding
morphological changes and the characteristic
appearance of ‘typical’ hiemoprogrediens. The
Plant Introduction • 109 11
Invasive insect pests of introduced plants of the “Оlexandria” Dendrological Park. Report 3
larvae of progrediens, whose development
before diapause was short, did not exhibit
corresponding morphological features in the
adult phase.
However, both the former and the latter
should be classified as hiemoprogrediens
based on the presence of winter diapause
in their development and the existence of
undeniable physiological differences with
aestivoprogrediens associated with their
adaptation to unfavorable living conditions
during the autumn-winter season.
The restoration of the full developmental
cycle of Eastern pine adelgid from the
paracycle after a three-year absence of the
primary host apparently indicates that not
only female individuals but also male ones
reproduce in the paracycle. This means that
the population isolated from the primary
host retains for some time the potential to
repopulate it in the future. It is unknown how
long this possibility remains. Suppose we
assume that Pineus orientalis and P. pini are
one species (Havelka et al., 2019) and consider
them as different races. In that case, P. pini is
a race that, as a result of very long isolation
from the primary host, has lost the male
developmental cycle. This means that the time
during which the holocycle can be restored is
finite.
As the research has revealed, the damage
caused by the pine adelgid to its primary host
is due, firstly, to gall formation, which usually
kills the damaged shoots, and secondly, to
the sucking of the female sexparas and their
offspring on the pine needles, causing them
to turn yellow and partially die. The direct
negative impact of the pest on the primary
host is limited to the first half of the season.
The nature of the damage caused by the
pine adelgid to the secondary host, the pine
tree, is determined by the fact that the pest
reproduces and feeds on it continuously,
without diapause, throughout the season.
During this period, up to six generations of
settlers develop in the secondary cycle. The
harmfulness of these generations is not the
same. The overwintering and first summer
generations cause the most tremendous
damage to pine trees. Densely populated by
settlers, young pine shoots may dry out, or
their growth may be significantly reduced,
and their needles may become smaller.
Subsequently, because of the remigration of a
significant part of the first summer generation
to spruce, the load on young shoots decreases
naturally. Precipitation (rain), which partially
washes away the adelgids, as well as the
activity of entomophages, also play a particular
role in reducing the number of adelgids. In
the summer, the presence of the pest on
pine trees becomes less noticeable due to its
secretive location on the plant and limited
feeding activity. This is reflected in a decrease
in the size and fertility of parthenogenetic
females in the second and subsequent summer
generations. Only in autumn is there a second
(after spring) peak in the activity of Pineus
orientalis on pine trees: the size and fertility
of reproducing females increase, as does the
amount of wax they produce.
Another significant result of the work
done is the experimental confirmation of
the impossibility of breaking the complete
life cycle of adelgids due to the temporary
isolation of the paracycle from the main
development cycle. In practical terms, this
means that planting eastern spruce in a habitat
populated by adelgids that develop only in a
secondary cycle on pine trees will inevitably
lead to its colonization by this pest.
Based on the data obtained, the following
practical conclusions can be drawn: planning
of protective measures against Pineus
orientalis should be timed to coincide with the
spring period on both pest-hosting plants and
in the secondary host in the fall.
Conclusions
It was found that the full life cycle of Pineus
orientalis is not fixed and consists of nine to
ten complete generations. In the paracycle,
P. orientalis develops up to six complete
generations in the secondary host.
It has been established that this species
lacks a specialized neotenic winter diapausing
form of sistentes on the secondary host.
All wingless settlers belong to one morph
– progredientes. The winter diapause in
pine is facultative and is not genetically
programmed. Individuals on the second host,
whether winter or summer, are biologically
identical and differ from each other only in
quantitative characteristics: the size and
degree of sclerotization of the body, as well as
the number of wax glands on it.
12 Plant Introduction • 109
Dragan
The life cycle of P. orientalis lacks the
winged form of settlers (alatae exsulantes). The
sexupara of this species, unlike other species,
feeds on spruce conifers before laying eggs.
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Plant Introduction • 109 13
Invasive insect pests of introduced plants of the “Оlexandria” Dendrological Park. Report 3
Інвазійні комахи-шкідники інтродукованих рослин дендрологічного парку
“Олександрія” НАН України. Повідомлення 3: щодо біології Pineus orientalis
(Dreyfus, 1889) (Heteroptera: Adelgidae)
Григорій Драган
Державний дендрологічний парк “Олександрія” НАН України, Біла Церква-13, Київська обл., 09113,
Україна; adragangid@gmail.com
У статті розглядаються проблеми, пов’язані з інтродукцією рослин та супутнім вторгненням нових
видів комах-шкідників у паркові насадження. Підкреслюється нагальна необхідність вивчення їхньої
біології. В статті описано деякі біологічні особливості одного з інвазійних видів – східного соснового
хермеса (Pineus orientalis). Вперше представлені дані про фенологію, особливості харчування і
розмноження, числу генерацій, складу морф життєвого циклу, а також шкодочинність P. orientalis.
Ключові слова: Pineus orientalis, інтродукція рослин, біологічні інвазії, повний цикл розвитку, побічний цикл розвитку, діапауза,
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|
| id | oai:ojs2.plantintroduction.org:article-1678 |
| institution | Plant Introduction |
| keywords_txt_mv | keywords |
| language | English |
| last_indexed | 2026-02-08T08:11:58Z |
| publishDate | 2026 |
| publisher | M.M. Gryshko National Botanical Garden of the NAS of Ukraine |
| record_format | ojs |
| resource_txt_mv | wwwplantintroductionorg/35/5642e4b94c5167ded2957c0652d4cf35.pdf |
| spelling | oai:ojs2.plantintroduction.org:article-16782026-01-09T02:00:58Z Invasive insect pests of introduced plants of the “Оlexandria” Dendrological Park. Report 3: towards a biology of Pineus orientalis (Dreyfus, 1889) (Heteroptera: Adelgidae) Інвазійні комахи-шкідники інтродукованих рослин дендрологічного парку “Олександрія” НАН України. Повідомлення 3: щодо біології Pineus orientalis (Dreyfus, 1889) (Heteroptera: Adelgidae) Dragan, Grygoriy The article discusses problems associated with the introduction of plants and the accompanying invasion of new species of insect pests into park plantings. It emphasises the urgent need to study their biology. The paper describes some biological features of one of the invasive species of pests – the Eastern pine adelgid, Pineus orientalis. The data on phenology, feeding and reproductive features, number of generations, composition of life cycle morphs, and damage caused by P. orientalis to its forage plants are presented. У статті розглядаються проблеми, пов’язані з інтродукцією рослин та супутнім вторгненням нових видів комах-шкідників у паркові насадження. Підкреслюється нагальна необхідність вивчення їхньої біології. В статті описано деякі біологічні особливості одного з інвазійних видів – східного соснового хермеса (Pineus orientalis). Вперше представлені дані про фенологію, особливості харчування і розмноження, числу генерацій, складу морф життєвого циклу, а також шкодочинність P. orientalis. M.M. Gryshko National Botanical Garden of the NAS of Ukraine 2026-01-08 Article Article application/pdf https://www.plantintroduction.org/index.php/pi/article/view/1678 10.46341/PI2025015 Plant Introduction; No 109 (2026): Early view; 3-13 Інтродукція Рослин; № 109 (2026): Early view; 3-13 2663-290X 1605-6574 en https://www.plantintroduction.org/index.php/pi/article/view/1678/1578 Copyright (c) 2026 Grygoriy Dragan http://creativecommons.org/licenses/by/4.0 |
| spellingShingle | Dragan, Grygoriy Інвазійні комахи-шкідники інтродукованих рослин дендрологічного парку “Олександрія” НАН України. Повідомлення 3: щодо біології Pineus orientalis (Dreyfus, 1889) (Heteroptera: Adelgidae) |
| title | Інвазійні комахи-шкідники інтродукованих рослин дендрологічного парку “Олександрія” НАН України. Повідомлення 3: щодо біології Pineus orientalis (Dreyfus, 1889) (Heteroptera: Adelgidae) |
| title_alt | Invasive insect pests of introduced plants of the “Оlexandria” Dendrological Park. Report 3: towards a biology of Pineus orientalis (Dreyfus, 1889) (Heteroptera: Adelgidae) |
| title_full | Інвазійні комахи-шкідники інтродукованих рослин дендрологічного парку “Олександрія” НАН України. Повідомлення 3: щодо біології Pineus orientalis (Dreyfus, 1889) (Heteroptera: Adelgidae) |
| title_fullStr | Інвазійні комахи-шкідники інтродукованих рослин дендрологічного парку “Олександрія” НАН України. Повідомлення 3: щодо біології Pineus orientalis (Dreyfus, 1889) (Heteroptera: Adelgidae) |
| title_full_unstemmed | Інвазійні комахи-шкідники інтродукованих рослин дендрологічного парку “Олександрія” НАН України. Повідомлення 3: щодо біології Pineus orientalis (Dreyfus, 1889) (Heteroptera: Adelgidae) |
| title_short | Інвазійні комахи-шкідники інтродукованих рослин дендрологічного парку “Олександрія” НАН України. Повідомлення 3: щодо біології Pineus orientalis (Dreyfus, 1889) (Heteroptera: Adelgidae) |
| title_sort | інвазійні комахи-шкідники інтродукованих рослин дендрологічного парку “олександрія” нан україни. повідомлення 3: щодо біології pineus orientalis (dreyfus, 1889) (heteroptera: adelgidae) |
| url | https://www.plantintroduction.org/index.php/pi/article/view/1678 |
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