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Longhorn beetles as new pests for exotic plantations in Vietnam

Authors:
  • Vietnamese Academy of Forest Sciences
  • Vietnamese Academy of Forest Sciences

Abstract and Figures

Longhorn beetles are important pests in commercial forests and exotic tree plantations worldwide, consequently leading to economic losses for timber producers and plantation owners. Acacia, Eucalyptus and Pinus plantations have been established widely in Vietnam for reforestation, wood products and paper industry. However, severe infestations of these three exotic trees have occurred due to longhorn beetles. The present study identified Coptops annulipes Gahan, 1894, Anagelasta apicalis Pic, 1925, Desisa subfasciata (Pascoe, 1862), and Cephalallus unicolor (Gahan, 1906) as four new longhorn beetles attacking Acacia crassicarpa in Quang Tri province, Eucalyptus hybrid (E. urophylla × E. grandis) in Bac Giang province, and Pinus caribaea in Quang Tri province, Vietnam. The infestation levels caused by C. annulipes, A. apicalis, D. subfasciata and C. unicolor were 16.8%, 29.5%, 39.2% and 24.3%, respectively. The damage indeces were 0.41, 0.85, 1.16 and 0.71, respectively. A. apicalis damaged at the base, C. annulipes and C. unicolor damaged at the lower trunk of host trees, D. subfasciata infested the top of trees. This information is expected to assist forest owners and government authorities across the country in pest surveillance and in developing suitable management plans for these four emerging pests.
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Ecologica Montenegrina, 70, 2023, 188-198
Longhorn beetles as new pests for exotic plantations in Vietnam
DUY LONG PHAM1, NGUYEN MINH CHI1*, VU VAN LOI1, DUONG NGOC DANH2,
NGUYEN THI KIM VUI2, PHAM TIEN HUNG2, LE CONG DINH2, NGOC LINH HA3,
& FRANCESCO VITALI4
1 Forest Protection Research Centre, Vietnamese Academy of Forest Sciences, Hanoi 11910, Vietnam.
https://orcid.org/0000-0002-0810-474X, https://orcid.org/0000-0002-9645-6867
2 Forest Science Centre for North of Central Vietnam, Vietnamese Academy of Forest Sciences, Dong Ha, Quang Tri
48065, Vietnam.
https://orcid.org/0009-0000-2941-2904, https://orcid.org/0009-0005-8630-0630,
https://orcid.org/0009-0000-2879-8390, https://orcid.org/0009-0002-0291-1812
3 Institute of Ecology and Biological Resources, Vietnam Academy of Science and Technology, Hanoi 113000, Vietnam.
https://orcid.org/0000-0002-1723-1230
4 National Museum of Natural History Luxembourg, Rue Münster 24, 2160 Luxembourg, Luxembourg.
https://orcid.org/0000-0003-3052-2910
* Corresponding author. E-mail: nguyenminhchi@vafs.gov.vn; https://orcid.org/0000-0002-2345-2398
Received 26 November 2023 │ Accepted by V. Pešić: 22 December 2023 │ Published online 26 December 2023.
Abstract
Longhorn beetles are important pests in commercial forests and exotic tree plantations worldwide, consequently leading
to economic losses for timber producers and plantation owners. Acacia, Eucalyptus and Pinus plantations have been
established widely in Vietnam for reforestation, wood products and paper industry. However, severe infestations of
these three exotic trees have occurred due to longhorn beetles. The present study identified Coptops annulipes Gahan,
1894, Anagelasta apicalis Pic, 1925, Desisa subfasciata (Pascoe, 1862), and Cephalallus unicolor (Gahan, 1906) as
four new longhorn beetles attacking Acacia crassicarpa in Quang Tri province, Eucalyptus hybrid (E. urophylla × E.
grandis) in Bac Giang province, and Pinus caribaea in Quang Tri province, Vietnam. The infestation levels caused by
C. annulipes, A. apicalis, D. subfasciata and C. unicolor were 16.8%, 29.5%, 39.2% and 24.3%, respectively. The
damage indeces were 0.41, 0.85, 1.16 and 0.71, respectively. A. apicalis damaged at the base, C. annulipes and C.
unicolor damaged at the lower trunk of host trees, D. subfasciata infested the top of trees. This information is expected
to assist forest owners and government authorities across the country in pest surveillance and in developing suitable
management plans for these four emerging pests.
Key words: Acacia crassicarpa, Anagelasta apicalis, Cephalallus unicolor, Coptops annulipes, Desisa
subfasciata, Eucalyptus, Pinus caribaea.
Introduction
Longhorn beetles (Coleoptera: Cerambycidae) are among the most diverse groups of beetles, with over
35,000 species described worldwide (Wang 2017). While many longhorn beetles are beneficial, some
Ecologica Montenegrina 70: 188-198 (2023)
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https://dx.doi.org/10.37828/em.2023.70.20
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Ecologica Montenegrina, 70, 2023, 188-198 189
species can become major insect pests of many hardwood trees, agricultural crops, fruit trees and
ornamental plants (Wang 2017; Thu et al. 2021). For instance, the Asian longhorn beetle, Anoplophora
glabripennis (Motschulsky, 1853) has become an invasive species attacking various broadleaf tree species in
Europe and North America (van der Gaag and Loomans 2014).
Acacia, Eucalyptus and Pinus are three of the most important genera for the forestry industry
worldwide due to their economic and ecological significance (Fimbel and Fimbel 1996; Arnold et al. 2020).
These trees have been widely utilised to establish intensively managed plantations, particularly in the tropics,
to meet the demand for reforestation, wood products, paper and other forest-related industries (Fimbel and
Fimbel 1996; Richardson et al. 2007; Nambiar and Harwood 2014). However, a range of longhorn beetles
have been reported as important insect pests for Acacia, Eucalyptus and Pinus species (Hanks et al. 1993;
Akbulut and Stamps 2012; Wang 2017). Many longhorn beetles have been recorded as serious pests in
Acacia plantations worldwide: Tithoes confinis (Laporte de Castelnau, 1840) on A. senegal and A. seyal in
Sudan (Jamal 1994), Plagithmysus claviger (Sharp, 1900) and P. varians Sharp, 1896 on A. koa in
Hawaii (Goldsmith et al. 2007), Lepturges guadeloupensis (Fleutiaux & Sallé, 1889) on A. farnesiana in
the Antilles (Wang 2017) and Xystrocera festiva on A. mangium in Vietnam (Thu et al. 2021). Several
species of the genus Phoracantha have been shown to infest Eucalyptus species in Australia and worldwide,
such as P. semipunctata (Fabricius, 1775) and P. recurva (Newman, 1840) on E. diversicolor, E. globulus, E.
grandis, E. nitens, E. saligna and E. viminalis in USA (Hanks et al. 1993), E. gomphocephala and E.
camaldulensis in Tunisia (Dhahri et al. 2016). In addition, some species of the genus Monochamus have
been shown to carry harmful pathogens that caused severe mortality of Pinus species in Holoarctic and
south-eastern Asia (Luzzi et al. 1984; Kobayashi 1988; Linit 1990; Bergdahl et al. 1991; Akbulut and
Stamps 2012).
In Vietnam, A. crassicarpa has been widely grown in sandy coastal areas for environmental
protection purposes and to provide wood chips and paper (Nirsatmanto and Sunarti 2019). Eucalyptus hybrid
(E. urophylla × E. grandis) is the most preferred for its growth rate, wood quality, disease resistance, and
tolerance to specific environmental conditions meanwhile P. caribaea is valued for its rapid growth, straight
stem form, and adaptability to extreme climates (Thu et al. 2021). Plantations of these three tree species have
been established widely for reforestation and afforestation efforts, helping restore degraded lands with
approximately 100,000 ha of A. crassicarpa plantation, 200,000 ha of Eucalyptus hybrid plantation, and
10,000 ha of P. caribaea plantation in 2021 (Thu et al. 2021; To et al. 2021a).
Prosoplus bankii (Fabricius, 1775) is the only longhorn beetle reported as host for A. crassicarpa
(Sirait et al. 2020), but Xystrocera globosa (Olivier, 1800), Trirachys holosericeus (Fabricius, 1787) and
Derolus volvulus (Fabricius, 1801) have been recorded causing damage to Acacia trees in south-eastern Asia
(Wang 2017). Some cerambycid species have been reported to attack Eucalyptus trees in the country, such as
Sarothrocera lowii White, 1846 (Thu and Cam 2008) and Batocera lineolata Chevrolat, 1852 (Quang et al.
2022a). Several insect pests have been recorded in P. caribaea plantations in Vietnam, such as the sawfly
Diprion sp. and the moths Dendrolimus punctatus (Walker, 1855) and Dioryctria sp. (Thu 2016), but no
damage caused by longhorn beetle has been found.
Exotic tree species play a very crucial role in the development of forestry economics and the
livelihoods of farmers in Vietnam (To et al. 2021a; To et al. 2021b). The total forest planted area of Acacia,
Eucalyptus and Pinus species in Vietnam is approximately 2.5, 0.4 and 0.3 million hectares, respectively (To
et al. 2021b; Vietnam 2021). The total annual revenue from the exploitation and processing of wood from
acacia, eucalypt and pine species contributes tens of billions of dollars to the Vietnamese economy (To et al.
2021a). With the area of forests planted with these tree species being forecast to increase (Vietnam 2021),
the risk of damage by pests is entirely possible. The objectives of this study were to identify new longhorn
beetles attacking A. crassicarpa, Eucalyptus hybrid and P. caribaea trees in plantations in Vietnam and
quantify the extent of the damage. This information will be valuable for forest owners and government
authorities across the region for pest surveillance and the development of suitable management plans to
address these emerging pests.
Materials and methods
Collection of longhorn beetles from plantations and rearing in laboratory
Twenty 10-year-old trees of Acacia crassicarpa with 5–10 holes/tree, and thirty 2-year-old trees of
Eucalyptus hybrid (E. urophylla × E. grandis) with 5–7 holes/tree were cut down in July 2023. Two 30-year-
NEW PESTS OF LONGHORN BEETLES FROM VIETNAM
190
old trees of Pinus caribaea with >500 holes/tree were cut down in June 2023; the boles were cut into 1.0 m
lengths and the logs were taken to Hanoi, where cerambycid larvae were collected manually and reared on a
laboratory by compound diets (Table 1) until adults were obtained.
Table 1. Artificial diet formulation (for 500 g) for rearing longhorn beetles damaging Acacia crassicarpa, Eucalyptus
hybrid and Pinus caribaea plantations in Vietnam.
Ingredients
Diets for beetle species
Diet 1
(Coptops)
Diet 2
(Anagelasta)
Diet 3
(Desisa)
Diet 4
(Cephalallus)
Agar (g) 24.2 24.2 24.2 24.2
Glucose (g) 32.2 32.2 32.2 32.2
Cellulose (g) 8.1 8.1 8.1 8.1
Yeast extract (g) 20.1 20.1 20.1 20.1
Rye flour (g) 48.3 48.3 48.3 48.3
Natri benzoate (g) 3.2 3.2 3.2 3.2
Sorbic acid (g) 1.6 1.6 1.6 1.6
Distilled water (ml) 241.5 241.5 241.5 241.5
Fresh Acacia crassicarpa phloem-cambium powder (g) 120.8
Fresh Eucalyptus hybrid phloem-cambium powder (g) 120.8 120.8
Fresh Pinus caribaea phloem-cambium powder (g) 120.8
Branches (4–5 cm in diameter, 1 m long) of 3-year-old A. crassicarpa trees, 2-year-old Eucalyptus
hybrid trees (7–8 cm in diameter, 7–9 m long), and branches of 10-year-old P. caribaea trees (7–8 cm in
diameter, 1 m long) were collected from plantations in Quang Tri and Bac Giang provinces; then, they were
sawn into 50–60 cm logs before being grilled into powder in the laboratory of Forest Protection Research
Centre, Hanoi (FPRC). The detailed composition of four artificial diets (Diet 1, Diet 2, Diet 3 and Diet 4)
was described in Table 1. The diet composition was modified from diets developed by Wu et al. (2017).
Initially, we put all diet components in a 1L pot, and then we mixed them with a magnetic stirrer on a heating
plate for 3 minutes. When completely solubilized, the solution was divided into 50 ml round-bottomed
polypropylene fancol bottles (28 mm in inner diameter), which were capped with silicon stoppers. Ten small
holes (0.5 mm in diameter) were created on the cap surface to allow the exchange of air in the course of
laboratory rearing. The test tubes filled with diets were then autoclaved at 121 oC for 20 minutes at a vapor
pressure of 1.2 kg/cm2 and placed in a tilled position until solidified.
One day after artificial diets were being prepared, larvae of longhorn beetles were manually
extracted from the infested host trees, which were collected from the field one day before. The larvae were
individually placed into bottles with artificial diets. In total, twenty larvae of each longhorn beetle species
were reared on the artificial diets. Environmental conditions were: temperature of the rearing room 25 ± 3
°C, the humidity 70–80%, photoperiod 14L:10D. All larvae were observed and artificial diets were replaced
weekly by carefully transferring the larvae to a new bottle of artificial diet. The larvae were reared in their
artificial diets until adult emergence.
Characterization and identification
Adult body length was measured along the midline from the anterior of the eye to the apex of the elytra, and
width was measured across the dorsal side at the widest point. Thirty adult specimens of each species were
deposited in the insect collection of the FPRC, 46 Duc Thang Ward, Bac Tu Liem District, Hanoi, Vietnam.
Assessment of damage and severity
For Acacia crassicarpa, field observations were carried out during June 2023 at 5–10 year-old plantations
in Quang Tri province, Vietnam. Plantations were 11–15 ha in size with 1660 trees/ha. This province has a
tropical monsoon climate with two distinct seasons; the mean annual rainfall is 2200–2300 mm and the mean
average temperature is 25–26 oC. Three plantations were selected and 4 plots, each 1000 m2, were randomly
laid out in each plantation. All 80 trees in each plot (ca. 12–18 cm in diameter at breast height and 11–16 m
height) were checked for attack symptoms and then, several holes were counted before dimension
PHAM ET AL.
Ecologica Montenegrina, 70, 2023, 188-198 191
measurement. The trunk holes were a combination of exit holes and exposed larval feeding sites. Damage
was classified at four levels: 0 = healthy trees; 1 = trees with 1–5 holes into the trunk; 2 = trees with 5–10
holes in the trunk, mild leaf senescence; 3 = more than 10 holes in the trunk, about 50% canopy senescing or
trees with full canopy senescence or trees dead. Damage was also observed in each plantation.
For Eucalyptus hybrid, field observations were carried out during May 2023 at 2-year-old
plantations in Bac Giang province, Vietnam. Plantations were 15–30 ha in size with 1660 trees/ha. This
location has a tropical monsoon climate with four distinct seasons; the mean annual rainfall is 1550–1600
mm and the mean average temperature is 23–24 oC. Three plantations were selected and 4 plots, each 500
m2, were randomly laid out in each plantation. All 80 trees in each plot (ca. 6–8 cm in diameter at breast
height and 9–11 m height) were checked for attacks and hole dimensions were measured. The trunk holes
were a combination of exit holes and exposed larval feeding sites. Damage was classified at four levels: 0 =
healthy trees; 1 = trees with 1–3 holes into the trunk, mild leaf senescence; 2 = trees with 4–6 holes in the
trunk, about 50% canopy senescing; 3 = more than 6 holes in the trunk, trees with full canopy senescence or
trees dead. Damage was also observed in each plantation.
Other field observations were carried out during June 2023 at 30–38 year-old trees of Pinus caribaea
plantations in Quang Tri province, Vietnam, where there was local concern for the decline of P. caribaea in
plantations. Plantations were 5–12 ha in size with 400–500 trees/ha. Three plantations were selected and 4
plots, each 1000 m2, were randomly laid out in each plantation. All 40 trees in each plot (ca. 40–60 cm in
diameter at breast height and 20–25 m height) were checked for attack symptoms and then, a number of
holes were counted before dimension measurement. The trunk holes were a combination of exit holes and
exposed larval feeding sites. Damage was classified at four levels: 0 = healthy trees; 1 = trees with 1–50
holes into the trunk; 2 = trees with 51–100 holes in the trunk, mild leaf senescence; 3 = more than 100 holes
in the trunk, about 50% canopy senescing or trees with full canopy senescence or trees dead. Damage was
also observed in each plantation.
Data analysis
Following the results of damage classification, damage incidence (P%) was calculated using equation (1):
P% = (n/N) × 100 (1)
where n is the number of trees attacked by longhorn beetles and N is total number of trees assessed.
The average damage index (DI) in each plot was calculated using equation (2):
DI = (Ʃni × vi)/N (2)
where ni is the number of infected trees at damage index I, vi is the damage index at level i and N is total
number of trees assessed.
Results
Identification
Based on the external morphological characters of adults in this study, the longhorn beetles infesting Acacia
crassicarpa in Quang Tri province were identified as Coptops annulipes Gahan, 1894 (Figs. 1A, B, C),
infesting Eucalyptus hybrid (E. urophylla × E. grandis) in Bac Giang province were identified as Anagelasta
apicalis Pic, 1925 (Figs. 2A, B, C) and Desisa subfasciata (Pascoe, 1862) (Figs. 3A, B, C), and infesting
Pinus caribaea in Quang Tri province were identified as Cephalallus unicolor (Gahan, 1906) (Figs. 4A, B,
C).
Damage symptoms
Coptops annulipes damage in Acacia crassicarpa
First and second-instar larvae initially feed on the inner bark and sapwood, and then tunnel deeper into the
heartwood thereby creating zigzag patterns inside the trunks. The feeding activity of the larvae causes
damage to trees and can be of concern in weakening and killing hosts. The gallery is 9–14 mm wide (Fig.
1D) and 26–35 cm long. The exit holes range from 11 to 12 mm in diameter, with a circular shape. Larvae
typically cause damage at a height of 1 to 3 m on host trunks and often attack trees affected by diseases or
mechanical damages because such trees may have weakened or compromised defenses, making them more
susceptible to infestations.
NEW PESTS OF LONGHORN BEETLES FROM VIETNAM
192
Figure 1. Coptops annulipes damage in Acacia crassicarpa in Quang Tri province: A, B, C. female adult; D.
damaged tree with holes on the stem (white arrows).
Anagelasta apicalis damage in Eucalyptus hybrid
First and second-instar larvae initially feed on the inner layers of the bark, including the phloem and the
stratum corneum. After feeding on the bark, larvae primarily bore into the layer of wood located beneath the
bark. Larvae tunnel through the sapwood, creating a zigzag pattern or serpentine galleries, 9.5–13.5 mm
wide and 26–35 cm long. Larvae complete their development and adults emerge through exit holes which are
11.5–12.5 mm in diameter. A. apicalis often causes damage at the base of host trees, 5–20 cm above the
ground (Fig. 2D), preferentially attacking trees under stress or disease. The density of larvae is sometimes
very high, A. apicalis causing significant damage by feeding all the wood layers at the base of tree and
consequently, causing host trees to die.
Desisa subfasciata damage in Eucalyptus hybrid
First and second-instar larvae initially feed the layered statue, then break it down, as they tunnel deeper into
the sapwood and create zigzag galleries at the top of the tree. Larval burrows are 8.6–12.4 mm wide and 16–
25 cm long. Exit holes range from 10 to 11.5 mm in diameter. D. subfasciata often infest the tops of trees, 1–
1.5 m away from the bud of the main top. Preferentially diseased host trees, potentially leading to branch
dieback or even tree death.
Cephalallus unicolor damage in Pinus caribaea
First-instar larvae feed on the inner shell, while second-instar larvae feed on the stratum corneum. Then,
larvae chisel into the sapwood of tree, where the wood is softer, and create zigzag or serpentine tunnels
within the trunk, 8.2–14.5 mm wide and 19–36 cm long (Fig. 4D). Exit holes range from 10.5 to 12.5 mm in
diameter. Infestation of C. unicolor targets the lower trunk of host trees, 1.5–4.5 m above the ground. C.
unicolor adults start laying eggs on host trees and continue causing damage closer to the point of egg-laying
until the hosts die. In case of severe infestations, the number of C. unicolor larvae in each tree reach hundred
of individuals, resulting in tree mortality due to large number of larvae quickly consuming the wood inner
layers and sapwood of host trees.
PHAM ET AL.
Ecologica Montenegrina, 70, 2023, 188-198 193
Figure 2. Anagelasta apicalis damage in Eucalyptus hybrid (E. urophylla × E. grandis) in Bac Giang province: A, B,
C. female adult; D. damaged tree with holes near the base.
Figure 3. Desisa subfasciata damage in Eucalyptus hybrid (E. urophylla × E. grandis) in Bac Giang province: A, B,
C. female adult; D. damaged tree with a hole on the top (white arrow).
NEW PESTS OF LONGHORN BEETLES FROM VIETNAM
194
Figure 4. Cephalallus unicolor damage in Pinus caribaea in Quang Tri province: A, B, C. female adult; D. damaged
tree with holes on the stem
Severity of longhorn beetles in host plants
This study has recorded the extent of damage (Table 2) caused by: Coptops annulipes in Acacia
crassicarpa plantations in Quang Tri province (P% = 16.8%; DI = 0.41); Anagelasta apicalis (P% =
29.5%; DI = 0.85) and Desisa subfasciata (P% = 39.2%; DI = 1.16) in Eucalyptus hybrid plantations in
Bac Giang province; Cephalallus unicolor in Pinus caribaea plantations in Quang Tri (P% = 24.3%; DI
= 0.71). In P. caribaea plantations, about 5–6% of trees are being newly damaged each year and at the
same time, trees attacked in previous years are severely damaged or die.
Table 2. Damage incidence and average damage index of four longhorn beetle species in exotic plantations in Vietnam.
Pest Location Acacia crassicarpa Eucalyptus hybrid Pinus caribaea
P% DI P% DI P% DI
Coptops annulipes Quang Tri 16.8±2.1 0.41±0.08 - - - -
Anagelasta apicalis Bac Giang - - 29.5±3.3 0.85±0.04 - -
Desisa subfasciata Bac Giang - - 39.2±4.5 1.16±0.12 - -
Cephalallus unicolor Quang Tri - - - - 24.3±2.6 0.71±0.07
Note: P% is damage incidence (%), DI is mean damage index.
Discussion
This is first record of damage of Coptops annulipes in Acacia crassicarpa, Anagelasta apicalis and
Desisa subfasciata in Eucalyptus hybrid and Cephalallus unicolor in Pinus caribaea.
1) Coptops annulipes is widespread in Cambodia, China, India, Indonesia, Laos, Malaysia,
Myanmar, Thailand, and Vietnam (Gahan 1894; Breuning 1967). The only known hosts of this species
were the pear (Pyrus communis) in Myanmar (Beeson and Bathia 1938) and the walnut (Juglans regia) in
China (Gahan 1894; Breuning 1967). This study has recorded that C. annulipes often attacks Acacia
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Ecologica Montenegrina, 70, 2023, 188-198 195
crassicarpa trees that were stressed due to mechanical damage or previous disease. Before having been
recorded causing damage to A. crassicarpa, this pest has never been recorded on any host plant species in
Vietnam.
2) Anagelasta apicalis and Desisa subfasciata have a fairly wide distribution (Gahan 1894;
Breuning 1967). Beeson and Bathia (1938) recorded the former species from Acacia sp., Adina cordifolia,
Bauhinia vahlii, Ficus rumphii, Mucuna imbricata, Shorea robusta and Terminalia tomentosa and the latter
one from Bauhinia vahlii and Mallotus philippensis. This is the first time that Eucalyptus hybrid has been
recorded as a host plant for these two pests.
Eucalyptus plantations in many countries have been damaged by longhorn beetles (Dell et al. 2012).
Batocera species can cause serious damage with great economic loss in Eucalyptus plantations: B.
rufomaculata (DeGeer, 1775) and B. numitor Newman, 1842 in India (Bhojvaid et al. 2014; Kumawat et
al. 2015), and B. horsfieldi (Hope, 1839) and B. lineolata in China (Dell et al. 2012; Zheng et al. 2016; Sun
et al. 2020). In India, Cerosterna scabrator (Fabricius, 1781) caused serious damage in Eucalyptus
plantations (Bhawane et al. 2015), as well as Trirachys holosericeus on E. robusta (Kariyanna et al. 2017).
In Vietnam, Sarothrocera lowii caused damage in Eucalyptus urophylla plantations (Thu and Cam 2008),
while Batocera lineolata caused serious damage in Eucalyptus hybrid plantations (Quang et al. 2022a).
However, the damage symptoms of A. apicalis and D. subfasciata on Eucalyptus hybrid trees in this study
have completely different characteristics compared to previous descriptions of damage symptoms for S. lowii
and B. lineolata. Without effective management solutions, A. apicalis and D. subfasciata will also become
pests that can cause great economic losses.
3) Cephalallus unicolor is widely distributed in south-eastern Asia from India to Japan (Gahan
1894; Breuning 1967). Pinus kesiya (= P. insularis) (Beeson and Bathia 1938, Gressitt 1951, Gressitt
and Rondon 1970, Hua 2002), P. luchuensis (Makihara et al. 2004), P. massoniana (Chu et al. 2021)
and Camellia oleifera (Hua 2002) have been recorded host plants. This study has recorded P. caribaea
as a new host plant of C. unicolor. Although newly recorded in Quang Tri province, Vietnam, the
damage of this pest is very serious. The density of larvae is very high, up to hundreds of larvae per
tree. After attacking the tree, they often eat all the libe and cause the tree to die.
Some beetles of the genus Monochamus have been shown to carry harmful pathogens caused severe
mortality of pine species (Pinus spp.) such as M. alternatus in P. alternatus, P. densiflora, P. thunbergii in
Japan and China (Kobayashi 1988), M. carolinesis, M. scutellatus, M. titillator, M. obtusus, M. notatus, M.
marmorator, M. mutator in P. sylvestris and P. elliottii in America (Luzzi et al. 1984; Linit 1990; Bergdahl
et al. 1991; Akbulut and Stamps 2012). In Vietnam, P. kesiya, P. massoniana, and P. merkusii plantations
have been attacked by Monochamus alternatus (Thu 2003; Thanh et al. 2019).
4) Future scenarios. The four newly recorded longhorn beetle species in this study all tend to
preferentially attack stressed trees. However, some studies have shown that some other longhorn
beetles, such as Batocera lineolata, Tapinolachnus lacordairei and Xystrocera festiva caused initial
damage to forestry plants on stressed trees but later, when their density was higher, they attacked even
healthy trees (Chi et al. 2021; Thu et al. 2021; Quang et al. 2022a). In another case, ambrosia beetles
(Euwallacea fornicatus and E. similis) were initially commonly recorded on stressed trees of Acacia
plantations in some locations in Vietnam but then, have caused widespread damage throughout the
country and attacked even healthy trees (Hung et al. 2022). Therefore, there is a need for continuous
monitoring of these four pests to have timely management solutions.
Some longhorn beetles, such as Batocera lineolata on Eucalyptus hybrid (Thu et al. 2021;
Quang et al. 2022a), Xystrocera festiva on A. mangium (Thu et al. 2021) and Bacchisa medioviolacea
Breuning, 1965 on Docynia indica (Quang et al. 2022b), have been recorded to appear and break out into
pest epidemics on some forestry plant species in Vietnam. Moreover, several new species have been
recorded in Vietnam in plantations very close to natural forests (Buchsbaum et al. 2022). The cause of their
sudden appearance and very rapid population outbreaks may be due to climate change and the shrinking of
the area of their preferred host tree species, possibly the decline that comes from natural forests. Hence,
future research directions should focus on determining the biological and ecological characteristics and
management solutions for these four pests.
NEW PESTS OF LONGHORN BEETLES FROM VIETNAM
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Acknowledgements
The authors would like to thank Mr. Nguyen Van Kiem, Hoang Tran Thi, and Ms. Nguyen Thi Thanh Nga
for their support in collecting samples.
References
Akbulut, S., Stamps, W.T. (2012) Insect vectors of the pinewood nematode: a review of the biology and
ecology of Monochamus species. Forest Pathology, 42 (2), 89–99.
https://doi.org/10.1111/j.1439-0329.2011.00733.x
Arnold, R.J., Xie, Y.J., Luo, J.Z., Wang, H.R., Midgley, S.J. (2020) A tale of two genera: Exotic Eucalyptus
and Acacia species in China. 2. Plantation resource development. International Forestry Review, 22
(2), 153–168. https://doi.org/10.1505/146554820829403441
Bergdahl, D.R., Halik, S., Tomminen, J., Akar, H. (1991) Frequency of infestation of Monochamus notatus
and M. scutellatus by Bursaphelenchus xylophilus in Vermont. Phytopathology, 81, 120.
Bhawane, G.P., Gaikwad, Y.B., Gaikwad, S.M., Mamlayya, A.B. (2015) Longicorn beetles and their diet
breadth from forests of Kolhapur district, Northern Western Ghats, Maharashtra. The Bioscan, 10
(2), 679–684.
Bhojvaid, P.P., Kaushik, S., Singh, Y.P., Kumar, D., Thapliyal, M., Barthwal, S., (2014) Eucalypts in India.
ENVIS Centre on Forestry, National Forest Library and Information Centre.
Breuning, S. (1967) Nouveaux Cerambycidae Lamiinae des collections du Muséum national d'Histoire
naturelle de Paris [Col.]. Bulletin de la Societe Entomologique de France, 72 (5), 183–189.
https://doi.org/10.3406/bsef.1967.20945
Buchsbaum, U., Grehan, J.R., Chen, M.Y., Chi, N.M., Pham, D.L., Khai, T.Q., Jones, L.D., Ignatev, N.
(2022) New species of Endoclita (C. and. R. Felder, 1874) and first record of E. salvazi from
Vietnam (Insecta: Lepidoptera: Hepialidae). Vernate, 41, 267–286.
Chi, N.M., Thanh, N.V., Quang, D.N., Thanh, L.B., Thao, D.V., Son, L.T., Hinh, T.X., Thu, P.Q., Dell, B.
(2021) First report of Tapinolachnus lacordairei (Coleoptera: Cerambycidae) damage in Chukrasia
tabularis. International Journal of Tropical Insect Science, 41 (1), 909–914.
https://doi.org/10.1007/s42690-020-00260-2
Dell, B., Xu, D., Thu, P.Q., (2012) Managing threats to the health of tree plantations in Asia. In: Bandani,
A.R. (Ed) New perspectives in plant protection. InTech, Rijeka, Croatia, pp 63–92.
Dhahri, S., Lieutier, F., Cheikhrouha, F.C., Ben Jamaa, M.L. (2016) Distribution, preference and
performance of Phoracantha recurva and Phoracantha semipunctata (coleoptera cerambycidae) on
various eucalyptus species in Tunisia. Redia, 99, 83–95.
https://doi.org/10.19263/redia-99.16.12
Fimbel, R.A., Fimbel, C.C. (1996) The role of exotic conifer plantations in rehabilitating degraded tropical
forest lands: A case study from the Kibale Forest in Uganda. Forest Ecology and Management, 81
(1), 215–226. https://doi.org/10.1016/0378-1127(95)03637-7
Gahan, C.J., (1894) A list of the longicorn Coleoptera: collected by Signor Fea in Burma and the Adjoining
regions, with descriptions of the new genera and species. Tipografia del R. Istituto Sordo-Muti.
Goldsmith, S., Gillespie, H., Weatherby, C. (2007) Restoration of Hawaiian montane wet forest: endemic
longhorned beetles (Cerambycidae: Plagithmysus) in koa (Fabaceae: Acacia koa) plantations and in
intact forest. The Southwestern Naturalist, 52 (3), 356–363.
https://doi.org/:10.1894/0038-4909(2007)52[356:ROHMWF]2.0.CO;2
Hanks, L.M., McElfresh, J.S., Millar, J.G., Paine, T.D. (1993) Phoracantha semipunctata (Coleoptera:
Cerambycidae), a serious pest of Eucalyptus in California: biology and laboratory-rearing
procedures. Annals of the Entomological Society of America, 86 (1), 96–102.
https://doi.org/10.1093/aesa/86.1.96sss
Hung, T.X., Thu, P.Q., Chi, N.M., Binh, L.V., Dell, B. (2022) Impacts and trapping of ambrosia beetles
Euwallacea fornicatus and E. similis in Acacia plantations in Vietnam. Southern Forests: a Journal
of Forest Science, 84 (3), 242–252. https://doi.org/10.2989/20702620.2022.2128931
Jamal, A. (1994) Major insect pests of gum arabic trees Acacia senegal Willd. and Acacia seyal L. in
western Sudan. Journal of Applied Entomology, 117 (1-5), 10–20.
PHAM ET AL.
Ecologica Montenegrina, 70, 2023, 188-198 197
https://doi.org/10.1111/j.1439-0418.1994.tb00702.x
Kariyanna, B., Mohan, M., Das, U., Biradar, R., Anusha Hugar, A. (2017) Important longhorn beetles
(Coleoptera: Cerambycidae) of horticulture crops. Journal of Entomology Zoology Studies, 5 (5),
1450–1455.
Kobayashi, F., (1988) The Japanese pine sawyer. In: Dynamics of forest insect populations: patterns, causes,
implications. Springer, pp 431–454.
Kumawat, M.M., Singh, K.M., Ramamurthy, V.V. (2015) A checklist of the long-horned beetles
(Coleoptera: Cerambycidae) of Arunachal Pradesh, northeastern India with several new reports.
Journal of Threatened Taxa, 7 (12), 7879–7901. https://doi.org/10.11609/JoTT.o4007.7879-901
Linit, M.J. (1990) Transmission of pinewood nematode through feeding wounds of Monochamus
carolinensis (Coleoptera: Cerambycidae). Journal of Nematology, 22 (2), 231.
Luzzi, M.A., Wilkinson, R.C., Tarjan, A.C. (1984) Transmission of the pinewood nematode,
Bursaphelenchus xylophilus, to slash pine trees and log bolts by a cerambycid beetle, Monochamus
titillator, in Florida. Journal of Nematology, 16 (1), 37.
Nambiar, E.K.S., Harwood, C.E. (2014) Productivity of acacia and eucalypt plantations in Southeast Asia. 1.
Bio-physical determinants of production: opportunities and challenges. International Forestry
Review, 16 (2), 225–248.
Nirsatmanto, A., Sunarti, S., (2019) Genetics and breeding of tropical acacias for forest products: Acacia
mangium, A. auriculiformis and A. crassicarpa. In: Al-Khayri J.M., Jain S.M., Johnson D.V. (Eds)
Advances in plant breeding strategies: industrial and food crops: volume 6. Springer International
Publishing, Cham, pp 3–28. https://doi.org/10.1007/978-3-030-23265-8_1
Quang, D.N., Chi, N.M., Thao, D.V., Thanh, L.B., Son, L.T., Chung, D.H., Minh, L.N., Dell, B. (2022a)
Damage caused by Batocera lineolata Chevrolat (Coleoptera: Cerambycidae) in Eucalyptus and its
management in Vietnam. International Journal of Tropical Insect Science, 42 (2), 1389–1399.
https://doi.org/10.1007/s42690-021-00659-5
Quang, D.N., Thu, P.Q., Binh, L.V., Pham, D.L., Thang, T.V., Tong, T.A., Thu, N.H., Thanh, N.V., Thong,
N.Q., Tiep, B.Q., Dell, B. (2022b) Damage caused by Bacchisa medioviolacea Breuning
(Coleoptera: Cerambycidae) in wild apple (Docynia indica) orchards in northwest Vietnam.
Horticulturae, 8 (12), 1219. https://doi.org/10.3390/horticulturae8121219
Richardson, D.M., Rundel, P.W., Jackson, S.T., Teskey, R.O., Aronson, J., Bytnerowicz, A., Wingfield,
M.J., Procheş, Ş. (2007) Human impacts in pine forests: Past, present, and future. Annual Review of
Ecology, Evolution, and Systematics, 38 (1), 275–297.
https://doi.org/10.1146/annurev.ecolsys.38.091206.095650
Sun, J., Dong, C., Tian, Y., Chen, B., Chen, G., Long, X., Chen, H., Bai, Y. (2020) Damage characteristics
of Batocera lineolata in Eucalyptus plantations in a large scale. Journal of Northwest A&F
University, 48, 34–46. https://doi.org/10.13207/j.cnki.jnwafu.2020.12.005
Thanh, N.V., Zhang, F.P., Quy, N.V., Xie, W.W. (2019) Analysis of morphological differences among
different geographical population of Monochamus alternatus. Asian Academic Research Journal of
Multidisciplinary, 6 (3), 89–98.
Thu, P.Q. (2003) Status of a pine wilt nematode in Vietnam. New Zealand Journal of Forestry Science, 33
(3), 336–342.
Thu, P.Q. (2016) Results of a survey of insect pests and diseases of the main forest plantation species in
Vietnam. Vietnam Journal of Forest Science, 1, 4257–4264.
Thu, P.Q., Cam, N.V. (2008) Longhorned beetle Sarothrocera lowi white damaged stem of Eucalyptus
urophylla S.T. Blake, clone U6 planted in Pleiku, Gia Lai. Science and Technology Journal of
Agriculture and Rural Development, 12, 91–95.
Thu, P.Q., Quang, D.N., Chi, N.M., Hung, T.X., Binh, L.V., Dell, B. (2021) New and emerging insect pest
and disease threats to forest plantations in Vietnam. Forests, 12 (10), 1301.
https://doi.org/10.3390/f12101301
To, X.P., Cao, T.C., Tran, L.H. (2021a) Vietnam export and import of timber: Status 2020 and trend 2021.
Vietfores.
To, X.P., Tran, L.H., Cao, T.C. (2021b) The source of Acacia wood in Vietnam, current status and trends.
Vietfores.
van der Gaag, D.J., Loomans, A.J.M. (2014) Host plants of Anoplophora glabripennis, a review. EPPO
Bulletin, 44 (3), 518–528. https://doi.org/10.1111/epp.12151
NEW PESTS OF LONGHORN BEETLES FROM VIETNAM
198
Vietnam (2021) Decision No. 523/QD-TTg dated 1/4/2021 of the Prime Minister of the Socialist Republic of
Vietnam on approving the Vietnam forestry development strategy for the period of 2021-2030, with
a vision to 2050. Hanoi, Vietnam.
Wang, Q. (2017) Cerambycid pests in agricultural and horticultural crops. In: Wang, Q. (Ed) Cerambycidae
of the world: biology pest management. CRC Press/Taylor Francis, Boca Raton, FL, pp 471–472.
Wu, S., Xia, F., Zhang, F. (2017) An artificial feed for the young larvae of Monochamus altematus and
preparation method. China Patent CN201710324582.2.
Zheng, X.L., Su, J., He, H.X., Yang, J.H., Kong, L.P., Yang, M., Yang, Z.D., Yang, X.H., Lu, W. (2016)
Incidences on Eucalyptus of two wood-boring insects, Batocera horsfieldi Hope, 1839 (Coleoptera:
Cerambycidae) and Endoclita signifer Waller, 1856 (Lepidoptera: Hepialidae) in China. Journal of
the Entomological Research Society, 18 (2), 23–31.
... The diversity of longhorn beetles (Coleoptera Cerambycidae) is not only in the large number of species but also in their hosts. In fact, their larvae feed on healthy living trees (van der Gaag & Loomans 2014;Haack 2017;Thu et al. 2021;Quang et al. 2022), on stressed trees that have been attacked by injury or disease Pham et al. 2023), and on harvested woods and wood products (Wagner et al. 1991;Eyre & Haack 2017;Kulinich et al. 2022). ...
... Previous research had documented this species feeding on trees of Pyrus communis L. in Myanmar (Beeson & Bhatia 1938), Juglans regia L. in China (Gahan 1894;Breuning 1967) and Acacia crassicarpa A. Cunn. ex Benth. in Vietnam (Pham et al. 2023). Gressitt (1951) recorded Batocera lineolata from many trees (Sapium sebiferum (= Triadica sebifera (L.) Small), Ligustrum sinense Lour., Quercus glandulifera Blume (= Q. serrata Murray), Castanea, Fagus, Morus, Ficus, Ulmus, Salix, Pasamia, Eriobthya, Paulownia, Setaria), but these hosts need confirmation due to past confusion with the sibling B. horsfieldi (Hope, 1839). ...
... Cephalallus unicolor was recorded from trees of Pinus kesiya Royle ex Gordon (Beeson & Bhatia 1938;Gressitt 1951;Gressitt & Rondon 1970;Hua et al. 2009), P. luchuensis Mayr (Makihara et al. 2004), P. massoniana (Chu et al. 2021), P. caribaea (Pham et al. 2023) and Camellia oleifera Abel (Hua et al. 2009), the last host being doubtful, as it is not a conifer. This study confirmed P. caribaea and P. massoniana as hosts for C. unicolor (Tab. ...
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