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The effect of three species of Eucalyptus on growth and fecundity of the Eucalyptus snout beetle (Gonipterus scutellatus)

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The Eucalyptus snout beetle, Gonipterus scutellatus , was first detected in NW Spain in 1991, in the area with the largest European eucalypt plantations. Feeding preferences in the field and the effect of three species of Eucalyptus on larval development, survival, and adult fertility were studied. It was estimated that individuals of G. scutellatus consume 1.2–1.7 g of fresh biomass in Eucalyptus cinerea and E. globulus during their development. Diet had a significant effect on larval survival and rate of development, the least suitable tree species being E. obliqua . Nevertheless, females fed with these eucalypt species or with an alternated diet containing all three eucalypts, did not produce significantly different numbers of larvae. In the field, G. scutellatus showed a marked preference for E. globulus, E. longifolia, E. grandis and E. propinqua , and completely avoided other species.
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Introduction
Eucalypt plantations are widespread in temperate
and tropical regions (Anonymous, 1997) because
they grow at a high rate even on poor soils,
making them highly productive. One of the
reasons for the high productivity of eucalypt
plantations in Europe is the absence of significant
herbivore losses, especially by insects. Neverthe-
less in their country of origin, eucalypts are dra-
matically affected by herbivore insects (Morrow,
1977; Fox and Morrow, 1983), and in many parts
of Australia, there is currently a generalized
dieback phenomenon due to repetitive insect
attacks (Lowman and Heatwole, 1992).
In Spain eucalypts are basically cultivated to
produce paper. Two species are widespread: E.
globulus Labill. (325 000 ha) and E. camaldulen-
sis Dehnh. (175 000 ha; Montoya, 1995). In
Galicia (NW Spain), monocultures of E. globulus
are a basic resource in areas where agriculture is
not profitable. There is a growing concern about
The effect of three species of
Eucalyptus
on growth and fecundity
of the
Eucalyptus
snout beetle
(
Gonipterus scutellatus
)
A. CORDERO RIVERA AND S. SANTOLAMAZZA CARBONE
Departmento de Ecoloxía e Bioloxía Animal, Universidade de Vigo, EUET Forestal, Campus Universitario,
36005 Pontevedra, Spain
Summary
The Eucalyptus snout beetle, Gonipterus scutellatus, was first detected in NW Spain in 1991, in the
area with the largest European eucalypt plantations. Feeding preferences in the field and the effect of
three species of Eucalyptus on larval development, survival, and adult fertility were studied. It was
estimated that individuals of G. scutellatus consume 1.2–1.7 g of fresh biomass in Eucalyptus
cinerea and E. globulus during their development. Diet had a significant effect on larval survival and
rate of development, the least suitable tree species being E. obliqua. Nevertheless, females fed with
these eucalypt species or with an alternated diet containing all three eucalypts, did not produce
significantly different numbers of larvae. In the field, G. scutellatus showed a marked preference for
E. globulus, E. longifolia, E. grandis and E. propinqua, and completely avoided other species.
© Institute of Chartered Foresters, 2000 Forestry, Vol. 73, No. 1, 2000
E-mail: acordero@uvigo.es
02 Cordero Rivera (jl/k) 5/1/00 1:31 pm Page 21
the ecological effects of eucalypt plantations
(Anonymous, 1997), mainly due to the losses of
biodiversity because there are almost no herbivore
insects feeding on E. globulus in the Iberian penin-
sula, which means that higher trophic levels are
also scarce (Paiva, 1992). Productivity in these
stands may reach a maximum of 60 m3ha21a21,
but the mean productivity is 20 m3ha21a21(Cal-
vo de Anta, 1992).
In theory, monocultures are intrinsically highly
susceptible to insect outbreaks. Three Australian
insect species have colonized NW Spain, but only
the Eucalyptus snout beetle, Gonipterus scutella-
tus Gyllenhal, has produced significant damage.
Outside Australia, G. scutellatus was first found
in South Africa in 1916 (Tooke, 1955), but it is
now widespread in Africa, America and Europe
(Mansilla and Pérez Otero, 1996). Damage to
eucalypts by G. scutellatus in South Africa is so
intense that its presence is a factor limiting euca-
lypt planting in some localities (Lowman and
Heatwole, 1992). Biological control of this
species by means of the importation of Anaphes
nitens (Hym. Mymaridae), an egg parasitoid, has
been highly successful in many areas (Tooke,
1955; Kidd and Jervis, 1997).
G. scutellatus was first found in 1991 in NW
Spain (Mansilla, 1992). It is now widespread and
causing severe defoliation to eucalypt stands. In
South Africa, susceptible varieties of E. viminalis
Labill. begin to be attacked when the tree is about
2 years old and at 60 months of age the average
height of these varieties is only 3.4 m, when the
resistant varieties have reached 7.12 m (Richard-
son and Meakins, 1986). This is a clear example
of the considerable losses that the attack of G.
scutellatus can cause in susceptible species.
G. scutellatus is a generalist herbivore of Euca-
lyptus spp. In Australia its favorite food plant is E.
viminalis (Tooke, 1955). In spite of this special-
ization, it has been recorded feeding on apple in
New Zealand and Australia (Moutia and Vinson,
1945; Frappa, 1950; Tooke, 1955). Where the bio-
logical control of G. scutellatus is unsuccessful, the
alternative is to use resistant host plant species.
Nevertheless, there are no studies on the effects of
different species of Eucalyptus on success of this
herbivore. The first aim of this study was to
measure the amount of biomass consumption and
the effect of three species of Eucalyptus on growth
and fecundity of G. scutellatus. Specific tests were
carried out to find if a varied diet could improve
female fecundity. If that were the case, a mixture
of different species in the same plot should be
avoided. Tests were also done to assess if this
species of beetle can use apple leaves as food.
Finally, the degree of attack by G. scutellatus was
measured on 20 species of Eucalyptus, to obtain
information on the resistant species that might be
used in highly attacked areas.
Methods
Feeding experiments
Three species of Eucalyptus were used in the
experiments: E. globulus, E. obliqua L’Herit. and
E. cinerea F. Muell. ex Benth., respectively a
frequently attacked species (and dominant in
Galician plantations), one rarely attacked and
one not attacked in South Africa (Tooke, 1935).
To determine if G. scutellatus can feed on apple,
apple leaves were provided to a group of 50 newly
hatched larvae. All experiments were carried out
in a climatic room at 21°C during 14 hours of
light and 19°C during 10 hours of darkness. The
humidity was 80 per cent. The first experiment
was carried out to evaluate the biomass con-
sumed during larval development. Three groups
of 16 newly hatched larvae each were raised on
leaves of the three eucalypt species. Offered leaves
were weighed to the nearest 0.1 mg, by means of
an electrobalance (Denver XE Series Model 50).
During the first week of life, larvae were main-
tained in pairs, in Petri dishes 5 cm in diameter.
The consumption obtained in this way was
divided by two to estimate the consumption per
larva. When larvae reached the second instar, they
were isolated in Petri dishes (9 cm diameter), to
evaluate individual larval consumption. Leaves
were carefully selected, to obtain two groups with
similar weight and surface area. Of these groups,
one leaf was offered as food to the larvae and the
other was used as a control to estimate the loss of
weight of the leaves. Fresh biomass consumption
was estimated by calculating the difference
between the initial weight and the final weight of
the leaf after 24 hours. This weight was corrected
by multiplying this value by the ratio between the
nal and initial weights of control leaves.
The second experiment was carried out to
evaluate the effect of eucalypt species on larval
development and survival and adult weight. It
22 FORESTRY
02 Cordero Rivera (jl/k) 5/1/00 1:31 pm Page 22
was carried out with 300 newly hatched larvae.
All the larvae emerged on the same day and were
randomly assigned to three treatments with two
replicates. Each group (50 larvae) received fresh
leaves of E. globulus, E. cinerea or E. obliqua
every 2 days. Larvae were maintained in 1-litre
plastic boxes until pupation. They were weighed
individually every 4 days. For pupation, larvae
were transferred to similar containers with 5 cm
of soil. Adults were weighed and sexed on the day
of their emergence (about 1 month later).
The third experiment was carried out to evalu-
ate the effect of eucalypt species on fecundity and
fertility of the female beetles. Adult G. scutellatus
were collected on 22 February 1997 near Pon-
tevedra (42°279N 8°369W) when they were start-
ing their reproductive activity. Adults were
maintained together and the spontaneously
formed pairs were randomly assigned to four
treatments (10 pairs per treatment). Three treat-
ments received fresh leaves of E. globulus, E.
obliqua or E. cinerea every 2 days. The fourth
treatment received one of the previous species
every other day, in an alternate way. Each pair was
kept in isolation in a tube 6 cm high by 3.5 cm
diameter. Females were maintained with the male
that they spontaneously accepted, since there is
experimental evidence that females of some
species can lay more or fewer eggs depending on
the characteristics of their mate (Eberhard, 1996).
Counts were made of the number of egg masses
laid each day and the number of emerged larvae
for 1 month (or until the death of the female).
Feeding preferences in the field
Feeding preferences were estimated in the eucalypt
plots (established in 1955) at the Center of Forest
Research of Lourizán (Pontevedra), at the end of
the period of reproduction of G. scutellatus in the
spring of 1996. To evaluate the preferences of G.
scutellatus for different species of eucalypts, at
least three trees per species were examined using
binoculars. Damage by G. scutellatus is very
characteristic and is concentrated on the terminal
buds. An arbitrary scale was used, varying from 0
(absence of damage) to 5 (all the terminal branches
severely attacked). If G. scutellatus has any prefer-
ence for certain species it has the opportunity to
choose among them in the same locality.
Results
Experiment 1. Leaf consumption in three species
of Eucalyptus
Figure 1 shows the daily biomass consumed by
the larvae. Results are similar for E. globulus and
EFFECT OF EUCALYPTUS SPECIES ON EUCALYPTUS SNOUT BEETLE 23
Figure 1. Daily biomass consumption by Gonipterus scutellatus larvae on three Eucalyptus species. The
minumum on days 16 and 17 for E. obliqua was due to a temporary unavailability of fresh leaves. Mean
± s.e.
02 Cordero Rivera (jl/k) 5/1/00 1:31 pm Page 23
E. cinerea, with a daily consumption around
0.10–0.15 g for mature larvae. Consumption was
lower towards the end of the feeding period for
E. globulus because some larvae reached the
prepupa and ceased feeding. By contrast, for E.
obliqua, leaf consumption in the first instar larvae
was very low and increased when the surviving
larvae reached the second instar. Daily consump-
tion remained around 0.2 g, with the exception of
days 15 and 16, due to the unavailability of fresh
leaves.
Throughout their development, larvae of G.
scutellatus consumed a quantity of biomass that
varied between 1.0 and 4.6 g (Table 1). Con-
sumption was significantly different between tree
species (ANOVA, F= 209.34 d.f. = 2, P< 0.001),
being specially high E. obliqua (test Scheffé, P<
0.05). This species had low palatability, so that it
was impossible to rear the 16 larvae initially used
for the experiment (see also below). No differ-
ences were detected in the consumption of leaves
of E. globulus and E. cinerea.
Experiment 2. Effect of food on the
development of G. scutellatus
Different feeding treatments had very significant
effects on survival probability (Figure 2). Larvae
fed with E. obliqua suffered a higher mortality
throughout the duration of the experiment. The
groups fed with E. globulus and E. cinerea fol-
lowed a very similar pattern, with the exception
of the emergence of the adults, where one of the
groups fed with E. globulus suffered a very high
mortality (whose cause was unknown) during the
pupal phase.
24 FORESTRY
Table 1: Leaf consumption estimates during larval development of Gonipterus scutellatus in three eucalypt
species
Species Leaf consumption (g) Minimum Maximum
globulus 1.73 ± 0.07 (16) 1.33 2.41
cinerea 1.24 ± 0.03 (16) 1.01 1.55
obliqua 3.49 ± 0.17 (11) 2.65 4.63
Figure 2. The effect of diet on the survival of Gonipterus scutellatus fed on three species of Eucalyptus. Mean
± s.e.
02 Cordero Rivera (jl/k) 5/1/00 1:31 pm Page 24
The growth curve is presented in Figure 3. It is
clear that larvae fed with E. obliqua grew more
slowly than those fed on the other two species.
The effects of eucalypt species on the weight of
larvae was significant from an early stage (3 days
of age) and was manifested clearly in the mature
larvae (ANOVA, P< 0.05 at all the ages). Signifi-
cant differences between replicates were found in
almost all the cases, and there was a food-repli-
cate interaction in some ages of larvae.
Taking into account the effect of sex on adult
weight (females are heavier than males), the
weights of the adults were also affected by the
food species (ANOVA, food, F= 3.502, d.f. = 2,
P= 0.034; replicate, F= 0.787, d.f. = 1, P= 0.377;
sex, F= 34.477, d.f. = 1, P< 0.0001; no inter-
action was significant). In this case the few adults
reared on E. obliqua weighed more than the other
treatments (Figure 3).
Experiment 3 Effect of food on fecundity and
fertility of female beetles
Significant differences were detected among treat-
ments in the number of egg masses laid (F= 4.85,
d.f. = 3, P= 0.006). The average values (± s.e.)
were 31.8 ± 1.8 egg masses (1.1 egg masses per
day) for the females fed with E. obliqua, 18.8 ±
3.3 (0.7 per day) for E. globulus, 22.1 ± 2.2 (0.8
per day) for E. cinerea and 22.8 ± 2.6 (0.8 per
day) for those that received the alternated food.
Nevertheless, the numbers of larvae that hatched
were not significantly different between treat-
ments: 186.1 ± 25.9 for E. obliqua, 112.1 ± 25.6
for E. globulus, 123.9 ± 17.6 for E. cinerea and
122.2 ± 20.8 for alternated food (F= 2.20, P=
0.105).
The fertility of the females tended to diminish
with increasing age (Figure 4; correlation between
age and number of larvae produced: E. globulus
Spearman r= 20.31, P= 0.098; E. cinerea, rs=
20.78, P< 0.001; alternate, rs= 20.58, P=
0.001), except for the group of females fed with
E. obliqua that increased their fertility around 20
days of age (rs= 0.03, P= 0.896).
Feeding preferences
The tests with young apple leaves indicated that
G. scutellatus cannot feed on this species of tree:
all the larvae died in 2–3 days, although they
tasted the offered leaves. Table 2 presents the
attack scores observed in different species of
Eucalyptus in the plots at the Center of Forest
Research of Lourizán (Pontevedra). The results
indicate that besides E. globulus, G. scutellatus
EFFECT OF EUCALYPTUS SPECIES ON EUCALYPTUS SNOUT BEETLE 25
Figure 3. The effect of feeding on three species of Eucalyptus on the growth rate of Gonipterus scutellatus.
Note that E. obliqua was clearly the worst diet. Mean ± s.e.
02 Cordero Rivera (jl/k) 5/1/00 1:31 pm Page 25
attacks preferably E. longifolia Link and Otto, E.
grandis Hill ex Maiden, E. propinqua Deane and
Maiden, E. ovata Labill., E. citriodora Hook. E.
viminalis and E. pauciflora Sieber ex Sprengel.
Samplings carried out in mixed plots agree
with the data presented above. G. scutellatus
clearly prefers to attack E. globulus rather than
E. obliqua in plots located in Lourizán, where
both species grow in mixture (Table 3). In
Folgoso (Forcarei), G. scutellatus showed again a
marked preference for E. globulus (Table 3). In
this locality, the density of G. scutellatus in E.
globulus reached a maximum of 78 egg masses
and more than 600 larvae in a tree of about 4 m
height, but only two attacked trees of E. camald-
ulensis were found among 50 examined. E.
camaldulensis has low palatability for G. scutel-
latus, but surprisingly not for European insect
fauna, since abundant geometrid larvae were
found feeding on this species.
Discussion
In the different countries where it has spread, G.
scutellatus has shown marked preferences for
several species of eucalypt. Tooke (1935, 1955)
presented a list of four groups of species in rela-
tion to the degree of attack observed in South
Africa. On the island of Mauritius E. robusta
Smith, E. tereticornis Smith and E. kirtoniana
Maiden are cited as the most susceptible (Williams
et al., 1951). In Kenya, the attacked species were
E. globulus, E. maidenia F. Muell., E. robusta and
E. smithii R.T. Baker, while E.saligna Smith and
26 FORESTRY
Figure 4. The effect of feeding on single Eucalyptus species or alternating species on fecundity of Gonipterus
scutellatus females. Age refers to days since the start of the experiment.
Table 2: The attack degree by Gonipterus scutellatus
on trees at the eucalypt plots of the Forest Research
Center of Lourizán (NW Spain) in May 1997. The
scale is arbitrary, from 5 (maximum attack) to 0 (no
attack). Mean ± s.e. (n)
Species Attack degree
globulus 5.0 ± 0.0 (3)
longifolia 5.0 ± 0.0 (3)
grandis 4.0 ± 0.0 (3)
propinqua 3.7 ± 0.3 (3)
ovata 2.7 ± 0.3 (3)
citriodora 2.5 ± 0.5 (2)
viminalis 2.0 ± 0.0 (3)
pauciflora 1.7 ± 0.7 (3)
microcorys 1.0 ± 0.8 (3)
rubida 0.8 ± 0.8 (4)
alpina 0.7 ± 0.7 (3)
dives 0.3 ± 0.3 (3)
pilularis 0.3 ± 0.3 (3)
saligna 0.3 ± 0.3 (3)
cornuta 0.0 ± 0.0 (3)
fastigata 0.0 ± 0.0 (3)
ficifolia 0.0 ± 0.0 (2)
niphoploia 0.0 ± 0.0 (3)
obliqua 0.0 ± 0.0 (2)
amygdalina 0.0 ± 0.0 (3)
02 Cordero Rivera (jl/k) 5/1/00 1:31 pm Page 26
E. citriodora were cited as practically immune
(Kevan, 1946). In Madagascar the most suscepti-
ble were E. cornuta, E. viminalis, E. punctata, E.
globulus, E. urnigera and E. rostrata (= E. camal-
dulensis) (Frappa, 1950). In Italy G. scutellatus
showed a clear preference for the leaves of E. glob-
ulus, not attacking the plants of E. cinerea, E.
gunnii Hook. f., E. polyanthemos Schauer, E. stu-
artiana and E. rostrata (Arzone and Meotto,
1978). Finally in Galicia only damages to E. glob-
ulus and E. obliqua have been reported (Mansilla
and Pérez Otero, 1996). Comparing the present
results with the literature it clearly emerges that
the species most cultivated in Galicia, E. globulus,
is one of the favorite species of G. scutellatus.
Nevertheless, the choice of eucalypt species by G.
scutellatus clearly depends on availability, as the
results of Clarke et al. (1998) indicate. They found
that in Tasmania, G. scutellatus avoids E. globu-
lus and E. viminalis, laying most eggs in E. pul-
chella Desf.
Among the species with the highest attacks in
Lourizán, all except E. grandis and E. citriodora
are mentioned by Tooke (1935) as highly suscep-
tible. E. grandis does not appear in Tooke’s list.
The difference in the susceptibility of E. citri-
odora may be due to varietal differences, as was
found for E. viminalis (Richardson and Meakins,
1986). On the other hand, the species least
attacked in Lourizán are also those mentioned by
Tooke (1935) as not very susceptible. The present
evaluation of the damage by G. scutellatus was
made without knowledge of Tooke’s list, and
therefore the results are independent. Clearly the
most susceptible species in South Africa and other
countries are the most susceptible in NW Spain.
Results of this study might therefore be used as a
guide to resistance in other countries.
It seems that G. scutellatus cannot survive on
apple leaves. The literature citations of this
species feeding on apples are probably due to
adults that may be found resting on different
species of plants, but they would not serve as a
substitute food.
Significant differences in the leaf consumption
by G. scutellatus were detected on the three
studied tree species. However, the method used to
estimate consumption is intrinsically subject to
high errors, due to the different morphologies and
densities of the leaves of the different species
(Waller and Jones, 1989). Results indicate that
the larvae of G. scutellatus consume approxi-
mately 11–15 times their final weight during their
development, when they are fed respectively with
E. cinerea or E. globulus, but the value rises to 27
times when the food is E. obliqua (the final weight
of the larvae fed with this species was significantly
smaller). Freitas (1991) fed the larvae of
Gonipterus gibberus with leaves of E. saligna, a
species lightly attacked according to Tooke
(1935). It was estimated that G. gibberus con-
sumed a total of about 12 times their weight,
using the method of Waldbauer (1962), that accu-
rately corrects for differences between the weight
of experimental and control leaves. The value
found in the present experiments with G. scutel-
latus fed with E. globulus and E. cinerea is there-
fore very similar, which suggests that the method
was acceptable. When the density of G. scutella-
tus larvae is very high, they can produce almost
complete defoliation of trees (one tree with 300
larvae can lose more than 500 g of fresh leaves).
Eucalyptus globulus is nevertheless highly resis-
tant to insect damage, because 50 per cent de-
foliation in spring or summer, but not in autumn,
does not significantly reduce initial height growth
EFFECT OF EUCALYPTUS SPECIES ON EUCALYPTUS SNOUT BEETLE 27
Table 3: The mean number of adults, egg masses and larvae of Gonipterus scutellatus, on different eucalypt
species. Trees were 1–4 m high
Species and locality Adults Egg masses Larvae
Lourizán, April 1996
globulus (n= 60) 0.4 ± 0.11 22.0 ± 2.83 1.7 ± 0.31
obliqua (n= 60) 0.05 ± 0.03 8.2 ± 1.76 0.2 ± 0.09
Forcarei, April 1997
globulus (n= 50) 0.4 ± 0.05 22.0 ± 3.11 147.2 ± 20.82
camaldulensis (n= 50) 0.0 ± 0.00 0.6 ± 0.09 2.7 ± 0.38
viminalis (n= 25) 0.1 ± 0.06 4.7 ± 2.96 5.8 ± 3.18
02 Cordero Rivera (jl/k) 5/1/00 1:31 pm Page 27
(Abbott and Wills, 1996). There are no estimates
of productivity losses due to G. scutellatus on E.
globulus, but if it behaves similarly to E. mar-
ginata, more frequent low intensity defoliations
will reduce growth more than less frequent higher
intensity defoliations (Abbott et al., 1993).
The results of experiment 2 indicate that not all
tree species are suitable. E. cinerea that supposedly
was a non-attacked species (Tooke, 1935; Arzone
and Meotto, 1978) was similar to E. globulus in
its palatability. E. obliqua, a species that is used
rarely in the field (Table 3), is not appropriate for
larval development of G. scutellatus. Surprisingly,
the few adults that emerged from larvae fed with
this species were heavier than individuals fed with
E. globulus or E. cinerea. This suggests that even
less palatable species might be used by the insect if
the preferred species are absent.
It is possible that if G. scutellatus has several
eucalypt species in the same plot the fecundity of
the females increases due to a richer diet. The
results of this study suggest that the planting of
several species with different palatabilities does
not increase the fertility of G. scutellatus. Never-
theless, only three species were tested, and it is
still possible that some combinations of species
could produce the mentioned effect.
The surprising result obtained with E. obliqua
and adult fecundity contrasts with the results
mentioned for larval feeding. This might be due
to females fed with E. obliqua being younger,
because they did not reduce their fertility with age
(Figure 4). The low fecundity of females fed with
E. globulus could be due to the fact that they were
fed from buds collected from trees showing little
attack, and for that reason the least palatable
trees of this species could have been selected
unconsciously. This suggests that there is vari-
ability to the attack by G. scutellatus within E.
globulus stands.
Acknowledgements
Funding was provided by the Galician Government
(Xunta de Galicia research project XUGA37101A95).
We thank Rozimar de Campos Pereira and Jose A.
Andrés Abad for their help in laboratory work.
References
Anonymous, 1997 State of the World’s Forests. FAO,
Rome, 200pp.
Abbott, I., van Heurck, P. and Burbridge, T. 1993
Impact of frequency and intensity of defoliation on
growth of Jarrah (Eucalyptus marginata): an experi-
mental study with saplings. For. Ecol. Manage. 56,
175–183.
Abbott, I. and Wills, A. 1996 Growth of young Euca-
lyptus globulus in plantations after manual defolia-
tion simulating insect herbivory. CALMScience 2,
129–132.
Arzone, A. and Meotto, F. 1978 Reperti biologici su
Gonipterus scutellatus Gyll. (Col. Curculionidae)
infestante gli eucalipti della Riviera Ligure. Redia 61,
205–222.
Calvo de Anta, R. 1992 El Eucalipto en Galicia. Sus
relaciones con el medio natural. Univerisidade de
Santiago de Compostela, Santiago de Compostela,
211pp.
Clarke, A.R., Paterson, S. and Pennington, P. 1998
Gonipterus scutellatus oviposition on seven naturally
co-occurring Eucalyptus species. For. Ecol. Manage.
110, 89–99.
Eberhard, W.G. 1996 Female Control: Sexual Selection
by Cryptic Female Choice. Princeton University
Press, Princeton, N.J., 501pp.
Fox, L.R. and Morrow, P.A. 1983 Estimates of damage
by herbivorous insects on Eucalyptus trees. Aust. J.
Ecol. 8, 139–147.
Frappa, C. 1950 Sur la présence de Gonipterus scutel-
latus Gyll. dans les peuplements d’Eucalyptus de
Madagascar et l’acclimatement d’Anaphoidea nitens
Gir., insecte auxiliaire parasite. Rev. Pathol. Veg.
Entolom. Agric. Fr. 29, 183–189.
Freitas, S. 1991 Observaçoes sobre a alimentaçao de
Gonipterus gibberus (Boisduval, 1835) (Coleoptera,
Curculionidae) em eucaliptos. An. Soc. Entomol.
Bras. 20, 333–338.
Kevan, D.K.M. 1946 The Eucalyptus weevil in East
Africa. East Afr. Agric. J. 12, 40–44.
Kidd, N.A.C. and Jervis, M.A. 1997 The impact of
parasitoids and predators on forest insect popu-
lations. In Forests and Insects. A.D. Watt, N.E. Stork
and M.D. Hunter (eds). Chapman and Hall, London,
49–68.
Lowman, M.D. and Heatwole, H. 1992 Spatial and
temporal variability in defoliation of Australian
eucalypts. Ecology 73, 129–142.
Mansilla, J.P. 1992 Presencia sobre Eucalyptus globu-
lus Labill de Gonipterus scutellatus Gyll. (Col. Cur-
culionidae) en Galicia. Bol. San. Veg. Plagas, 18,
547–554.
Mansilla, J.P. and Pérez Otero, R. 1996 El defoliador
del eucalipto Gonipterus scutellatus. Phytoma
(España) 81, 36–42.
Montoya, J.M. 1995 El eucalipto. Mundi-Prensa,
Madrid, 125pp.
Morrow, P.A. 1977 The significance of phytophagous
28 FORESTRY
02 Cordero Rivera (jl/k) 5/1/00 1:31 pm Page 28
insects in the Eucalyptus forests of Australia. In The
Role of Arthropods in Forest Ecosystems. W.J.
Mattson (ed.). Springer-Verlag, New York, 19–29.
Moutia, L.A. and Vinson, J. 1945 Le charançon de l’Eu-
calyptus, Gonipterus scutellatus Gyll. Rev. Agricole
et Sucriere de l’Ile Maurice 24, 25–30.
Paiva, J. 1992 As plantacións de eucaliptos e a flora e
fauna portugesa. Cadernos da Área de Ciencias
Biolóxicas. Seminario de Estudos Galegos 4, 71–84.
Richardson, K.F. and Meakins, R.H. 1986 Inter- and
intra-specific variation in the susceptibility of eucalypts
to the snout beetle Gonipterus scutellatus Gyll.
(Coleoptera: Curculionidae). S. Afr. For. J. 139, 21–31.
Tooke, F.G.C. 1935 The eucalyptus snout beetle. Extent
to which different kinds of Eucalyptus are attacked.
Fmg S. Afr. 10, 174.
Tooke, F.G.C. 1955 The Eucalyptus snout-beetle,
Gonipterus scutellatus Gyll. A study of its ecology
and control by biological means. Ent. Mem. Dept.
Agric. U. S. Afr. 3, 1–282.
Waldbauer, G.P. 1962 The growth and reproduction of
maxillectomized tobacco hornworms feeding on
normally rejected non-solanaceous plants. Entomol.
Exp. Appl. 5, 147–158.
Waller, D.A. and Jones, C.G. 1989 Measuring her-
bivory. Ecol. Entomol. 14, 479–481.
Williams, J.R., Moutia, L.A. and Hermelin, P.R. 1951
The biological control of Gonipterus scutellatus Gyll.
(Col. Curculionidae) in Mauritius. Bull. Entomol.
Res. 42, 23–28.
Received 20 October 1998
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... One of these is the eucalyptus weevil, Gonipterus platensis Marelli (Coleoptera: Curculionidae), a specialist insect native to Eastern Australia that feeds on eucalypts' new foliage causing severe defoliation in the tree crown (EPPO, 2005;Mapondera et al., 2012). It has economically impacted plantations within Europe (France, Italy, Portugal, and Spain) (Cordero-Rivera and Santolamazza-Carbone, 2000;EPPO, 2005;Reis et al., 2012;Valente et al., 2018), North America (California) (Paine and Millar, 2002), South America (Argentina, Brazil, Chile, and Uruguay) (Lanfranco and Dungey, 2001;Huerta-Fuentes et al., 2008), and Oceania (New Zealand and Southwestern Australia) (Loch and Floyd, 2001;Withers, 2001;Loch and Matsuki, 2010). Based on the damage it usually causes, its quarantine and obliged control have been implemented in some of the countries mentioned above (Beéche Cisternas et al., 1999;EPPO, 2018). ...
... One of these is the eucalyptus weevil, Gonipterus platensis Marelli (Coleoptera: Curculionidae), a specialist insect native to Eastern Australia that feeds on eucalypts' new foliage causing severe defoliation in the tree crown (EPPO, 2005;Mapondera et al., 2012). It has economically impacted plantations within Europe (France, Italy, Portugal, and Spain) (Cordero-Rivera and Santolamazza-Carbone, 2000;EPPO, 2005;Reis et al., 2012;Valente et al., 2018), North America (California) (Paine and Millar, 2002), South America (Argentina, Brazil, Chile, and Uruguay) (Lanfranco and Dungey, 2001;Huerta-Fuentes et al., 2008), and Oceania (New Zealand and Southwestern Australia) (Loch and Floyd, 2001;Withers, 2001;Loch and Matsuki, 2010). Based on the damage it usually causes, its quarantine and obliged control have been implemented in some of the countries mentioned above (Beéche Cisternas et al., 1999;EPPO, 2018). ...
Article
Defoliation caused by Gonipterus platensis on Eucalyptus seriously impacts tree growth rate and forest production. The weevil’s feeding preference has sometimes limited which species of Eucalyptus to plant, although the plant’s metabolic features that govern such choice still need to be uncovered. We used metabolomics to reveal the chemical traits mediating this interaction, focusing on a model formed by two Eucalyptus species with markedly different susceptibility, E. globulus (susceptible), and E. nitens (resistant). Our results suggest that the insect’s feeding preference strongly depends on the Eucalyptus species’ constitutive metabolome, especially on the stilbenes and hydrolysable tannins accumulation. The susceptible E. globulus could not produce such classes of metabolite either constitutively or after herbivory, which indicated an apparent lack of critical enzymes for biosynthesis of these substances, such as stilbene synthase (STS) and gallate 1-β-glucosyltransferase. On the other hand, it seems that no matter how toxic the systemic defense induced in E. globulus after herbivory could be to an insect, counteradaptations, apparently evolved by the weevil, may efficiently detoxify them. This may result from plant-insect coevolution, given their common geographical origin. Inter-specific hybridizations between E. nitens and E. globulus have adapted hybrid species better to low temperatures and frost conditions, consequently being propagated for plantations in temperate regions. Thus, this research lays the groundwork for selecting the best parent genotypes and obtained hybrids, aiming to warrant the transfer of key resistance traits to progenies as an attractive strategy for future breeding programs.
... E. globulus is consistently found to be a preferred host in countries where G. platensis is present, even though several other eucalypt species have also been identified as susceptible (Cordero Rivera, 2000;Hanks et al., 2000;Lanfranco and Dungey, 2001). Furthermore, differences in susceptibility between species are less pronounced at high attack intensity (Gonçalves et al., 2019). ...
Article
Plantations of Eucalyptus species have been widely used in Spain to meet the high demand for wood given their rapid growth and high wood production capacity. Defoliation induced by the invasive eucalypt weevil (Gonipterus platensis (Marelli)), however, has been causing significant economic damage to Spanish Eucalyptus spp. plantations since the 1990s. G. platensis is native to Tasmania, Australia, where populations are controlled by natural enemies including the egg parasitoid Anaphes nitens Girault. In this study, spatio-temporal Universal Kriging was applied to examine the dynamics of defoliation damage caused by G. platensis in Spanish Eucalyptus spp. plantations and to identify the main factors associated with the presence and spread of the pest. The data set combines the Spanish national plots belonging to the network of the European transnational survey of forest condition in Europe (ICP Forest Level I, 16 × 16 km grid) along with regional plots, measured using similar field protocols, in which Eucalyptus spp. are present. A total of 264 Eucalyptus plots were included in the study, G. platensis being present in 167 of these plots at some time during the observed period (2005–2020). Our results show that defoliation damage > 0% and defoliation damage > 5% caused by G. platensis increased over the period 2005–2010 and then decreased between 2010 and 2020. Defoliation damage > 15% incidence steadily decreased from 2005 to 2015, but showed an upturn in 2020. Stands belonging to the Atlantic region are more affected by this pest (76% of the Atlantic sampling plots affected versus just 4% of the Mediterranean plots). The species Eucalyptus globulus Labill. and monospecific stands, as well as spring precipitation of the current year were found to be positively associated with the incidence of G. platensis whereas the relationship with summer temperature of the previous year was negative. Finally, maps showing the degree of incidence over time have been produced to support decision-making for pest prevention and control. This study puts forward a methodology which allows the spread of this pest to be better understood and simulated, thus facilitating risk prevention.
... O gorgulho-do-eucalipto é um exemplo de uma praga para a qual a suscetibilidade de diferentes espécies de eucaliptos tem sido investigada e usada como medida de mitigação. Nos países onde o gorgulho-do-eucalipto está presente, a espécie Eucalyptus globulus é consistentemente considerada um dos hospedeiros mais suscetíveis, estando outras espécies de eucalipto identificadas como mais resistentes ou tolerantes(HANKS et al., 2000;RIVERA and CARBONE, 2000;LANFRANCO and DUNGEY, 2001;. A espécie Eucalyptus nitens, sendo menos atacada pelo inseto, tem sido amplamente plantada como alternativa a E. globulus, sobretudo em áreas de forte incidência da praga no norte de Espanha. ...
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O eucalipto tornou-se uma das espécies incontornáveis da floresta portuguesa. Nos últimos anos, a ocorrência de grandes incêndios tem vindo a aumentar (onde os ocorridos em junho e outubro de 2017 foram particularmente significativos), acentuando a polémica em torno do efeito das plantações de eucalipto na propagação do fogo. Do protagonismo socioeconómico, aumento de área plantada e relação com o fogo resultam discussões apaixonadas, mas nem sempre fundamentadas no conhecimento existente. A informação disponível permite esclarecer dúvidas e recentrar o problema nos fatores que têm realmente influência nos regimes de fogo: as dinâmicas demográficas e de uso do solo que ocorreram no último século e a necessidade de encarar a floresta para além da árvore, como um sistema complexo. É a estrutura dos povoamentos, mais do que as espécies, que condiciona a propagação dos incêndios. Embora o problema dos incêndios, grandes e pequenos, seja territorial e não apenas do sector florestal, a solução passa pela gestão do uso do solo e do espaço rural, incluindo a floresta. Ao nível do ordenamento do território, a diversificação da paisagem e a redução da área florestal nalgumas zonas, quebrando a continuidade da vegetação, são algumas das soluções possíveis. À escala da árvore e da propriedade, a gestão florestal é a única ferramenta que permite conviver com o fogo e minimizar os danos causados pelos incêndios. É possível fazer melhor com os recursos disponíveis, adequando as opções de gestão às condições locais, numa perspectiva integrada à escala da paisagem, que considera as suas múltiplas dimensões: social, ambiental e económica. Este artigo faz parte do Caderno Técnico da Silva Lusitana sobre Eucalipto em Portugal. Tem como ponto de partida a obra "O Eucaliptal em Portugal. Impactes Ambientais e Investigação Científica" publicada em 2007 e procura dar visibilidade a algum do conhecimento científico desenvolvido nos últimos 10-15 anos sobre plantações de eucalipto e o fogo.
... Egg capsules of Gonipterus are laid on tender expanding leaves that will provide suitable food for the newly hatched larvae, which feed on the soft tissue (Tooke, 1955). Later on, larvae continue to rely on tender foliage to feed, consuming up to 15 times their own final body weight (Freitas, 1991;Cordero-Rivera and Santolamazza-Carbone, 2000;Virgala et al., 2018). Similar associations between peaks oviposition and rainfall when temperatures are adequate for weevil development have been observed elsewhere (Tribe, 2005;Loch, 2006). ...
Article
Gonipterus is a genus of defoliating weevils that causes significant impact in commercially grown eucalypts in their native range in southern Australia and as invasive pests in Western Australia and several countries overseas. The diversity of species in this genus is still in the process of discovery, and in subtropical Australia, its diversity and ecological parameters are largely unknown. We surveyed Gonipterus phenology, species composition and trophic associations in South East Queensland, where little has been recorded about this genus. Surveys were conducted once a month in a non-commercial plantation of native eucalypts, where three species of trees were sampled regularly and others checked on an ad hoc basis. On each sampling occasion, adult weevils, larvae and egg capsules were collected, adults identified, larvae reared and egg capsules individualized in small containers for emergence of larvae and parasitoids. Two peaks of egg-laying occurred, whereas numbers of adults and larvae had only one peak each. Six species of Gonipterus were collected: two described but in need of revision, two undescribed but previously recognized and two undescribed and hitherto unrecognized, each with a different pattern of host–tree association. Three egg-parasitoid species, Anaphes nitens, Centrodora damoni and Euderus sp. were reared from egg capsules, varying in prevalence according to the tree species from which the eggs were collected.
... For example, for augmentative biological control, 170 species of parasitoids are used only in Europe [8]. In some cases, the effectiveness of biological control is up to 100%, e.g., the wasp Cosmocomoidea ashmeadi (Girault, 1915) (Hymenoptera: Mymaridae) controlling the leafhopper Homalodisca coagulata (Say, 1832) (Hemiptera: Cicadellidae) [13], or Anaphes nitens (Girault, 1928) (Hymenoptera: Mymaridae) against the weevil Gonipterus scutellatus Gyllenhal, 1833 (Coleoptera: Curculionidae) [14,15]. Many parasitoids do not have 100% efficiency, and therefore, methods for improving the effectiveness of natural enemies or biological control have been sought [16]. ...
Article
Full-text available
The parasitic wasp Anaphes flavipes (Förster, 1841) (Hymenoptera: Mymaridae) is an important egg parasitoid of cereal leaf beetles. Some species of cereal leaf beetle co-occur in the same localities, but the host specificity of the wasp to these crop pests has not yet been examined in detail. A lack of knowledge of host specificity can have a negative effect on the use of this wasps in biological control programs addressed to specific pest species or genus. In this study, laboratory experiments were conducted to assess the host specificity of A. flavipes for three species of cereal leaf beetles (Oulema duftschmidi Redtenbacher, 1874, Oulema gallaeciana Heyden, 1879 and Oulema melanopus Linnaeus, 1758) in central Europe. For the first time, a new host defence against egg parasitoids occurring in O. gallaeciana from localities in the Czech Republic, a strong dark sticky layer on the egg surface, was found and described. The host specificity of A. flavipes was studied in the locality with the presence of this defence on O. gallaeciana eggs (the dark sticky layer) (Czech Republic) and in a control locality (Germany), where no such host defence was observed. Contrary to the idea that a host defence mechanism can change the host specificity of parasitoids, the wasps from these two localities did not display any differences in that. Respectively, even though it has been observed that eggs with sticky dark layer can prevent parasitization, the overall rate of parasitization of the three species of cereal beetles has not been affected. However, in our view, new host defence can influence the effects of biological control, as eggs of all Oulema spp. in the locality are protected against parasitization from the wasps stuck on the sticky layer of the host eggs of O. gallaeciana.
Article
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Background Gonipterus platensis Marelli (Coleoptera: Curculionidae) is the main defoliating beetle of Eucalyptus L’Hér. (Myrtaceae) plants worldwide. The suitability of Eucalyptus to this pest varies among host plant genotypes. The objective of this study was to evaluate the development, reproduction, and survival of G. platensis on Eucalyptus species and hybrids to assess their suitability to this insect pest in Brazil. Methods The survival, development, and reproduction parameters were evaluated with G. platensis feeding leaves of Eucalyptus camaldulensis Dehnh., Eucalyptus grandis W. Hill., Eucalyptus urophylla S.T. Blake and on the hybrids of E. grandis × E. urophylla ‘H13’ and ‘VR3748’ in the laboratory. Results The duration of the larval stage of G. platensis was shorter on E. urophylla. The pupal stage and the period from larva to adult were equally shorter on E. urophylla and E. camaldulensis . The viability of instars of this insect was low on both E. grandis and E. camaldulensis . The complete lifespan, oviposition period and reproduction parameters of G. platensis were greater on E. urophylla , lower on E. camaldulensis and E. grandis , and intermediate on both hybrids tested. Synthesis Eucalyptus urophylla is the most suitable host for G. platensis survival, development, and reproduction, while E. grandis and E. camaldulensis are the least suitable.
Thesis
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Se analiza la evolución de los viveros forestales gallegos, con un estudio detallado de los viveros de mayor importancia histórica, que son los instalados en el primer tercio del siglo XX. Se recopia la evolución de las técnicas de producción de planta y del uso de planta en repoblación, particularmente para los períodos correspondientes al Patrimonio Forestal del estado, el ICONA y la Xunta de Galicia. Se obtiene la información detallada sobre la tipología actual de viveros forestales y sobre la actividad de venta de planta a repobladores directos durante un periodo de seis años. Ello permite conocer el nivel de uso por especie y estimar, por primera vez en Galicia, la cifra global de repoblaciones anuales. Se estudia la evolución durante estos seis años, relacionándola con el proceso de concesión de ayudas a la reforestación de tierras agrarias. La recopilación de todos los datos referidos a estas últimas permite analizar por concello la actividad repobladora. Por último se realiza un estudio detallado de los medios de producción y resultados económicos de los viveros existentes, obteniéndos ecuaciones de regresión que permiten estimar el beneficio anual de explotación según los niveles de venta de planta. Se concluye la importancia actual del subsector de los viveros forestales gallegos y de la actividad repobladora en su conjunto, con una concentración de la actividad en un número reducido de especies y una tendencia a la producción de planta en contenedor en viveros de carácter industrial.
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Illustrated keys to females and males of the European genera and subgenera of Mymaridae (Chalcidoidea) are presented, including twenty-four genera plus two subgenera in both of Erythmelus Enock and Polynema Haliday. The key to females also includes three subgenera recognized in Anagrus Haliday, two subgenera in Anaphes Haliday, and two species groups in Anagrus s.s.; males of these either cannot be distinguished or are difficult to key. The species of Mymaridae recorded from the Czech Republic are listed and distribution records are provided based on material in three collections. Seven genera (Anagrus, Caraphractus Walker, Dicopus Enock, Macrocamptoptera Girault, Omyomymar Schauff, Pseudocleruchus Donev & Huber, Stethynium Enock) and 12 species are newly recorded for the country.
Chapter
Ninety-two percent of the forests and woodlands of Australia are dominated by evergreen hardwoods of the genus Eucalyptus (Myrtaceae), an endemic genus of more than 600 species (Pryor and Johnson, 1971). Apart from this dominance of the forests by a single genus, there are at least three related aspects of Australian forests which are of considerable ecological interest: (1) Eucalyptus species frequently have sharply defined, narrow geographical ranges which are closely associated with local environmental factors such as aspect (Pook and Moore, 1966), drainage (Florence, 1971), and especially, changes in soil chemistry (Beadle, 1954; C. Moore, 1959; Winterhalter, 1963; Parsons and Specht, 1966). (2) Despite their apparent specialization to particular edaphic or microclimatic conditions, Eucalyptus species rarely form monospecific stands. Instead, species tend to have overlapping ranges so that any particular set of environmental conditions is usually characterized by a stable mixture of from two to five species (Pryor, 1959). Eucalypt forests are, therefore, complex mosaics of quite sharply delineated plant associations. Pryor (19 53) showed that as many as 12 different associations may be present in one square mile of forest.
Article
Insect defoliation is commonly associated with and assumed to be a cause of mortality in Australian eucalypts, particularly in rural regions where trees suffer from the eucalypt dieback syndrome. To test this, leaf growth and defoliation were measured in the canopies of Eucalpyptus trees from June 1982 to June 1986, and related to tree health and eucalypt dieback. Over 5000 leaves were monitored, including replicates of branches, canopy heights, individual trees, species, and sites. Three types of sites were selected, representing the most common conditions in the eastern Australian tablelands: woodlands (comprised of healthy trees but with slight signs of dieback), healthy trees in pastures, and dying trees in pastures. Within each site the commonest native tree species were selected for study; species were not always the same between adjacent sites because of interspe_kw canopy
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Gonipterus scutellatus is a significant insect pest of eucalypts in most countries where that genus has been introduced, but is usually only of minor significance in its native Australia. Because of this, much of the research on its biology and host preferences has been done outside Australia. This fact has the potential to produce misleading results as the insect may be forced to choose less preferred hosts, if normally preferred species are unavailable. In part of its native range, in Tasmania, oviposition of G. scutellatus was recorded on seven naturally co-occurring Eucalyptus species that were planted in even aged, replicated plots. Among the seven species were the economically important species, E. globulus and E. viminalis, which have been previously reported as highly preferred hosts. Within plots, oviposition occurred most commonly on three peppermint species (E. pulchella, E. tenuiramis and E. amygdalina) and was rare or absent on the other species (E. globulus, E. viminalis, E. ovata and E. obliqua). Of the peppermints, E. pulchella was the most preferred species for oviposition at this site. A low percentage of peppermints in mixed forest (containing these seven species) immediately adjacent to plots was always matched by low numbers of G. scutellatus eggs within plots; but high percentages of peppermints outside plots could either be matched by high or low numbers of eggs within plots. In the discussion, we suggest that previous studies of G. scutellatus host range may have been limited because the insect was not exposed to hosts it naturally encounters.
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A review of the international status of the eucalyptus snout beetle as a pest of exotic eucalypts highlights the insect's role in restricting species choice for forestry in many countries, especially in southern Africa. Elsewhere, commercially important plantations covering hundreds of thousands of hectares remain at risk. Natural control is not effective in colder areas where some tree species susceptible to the beetle would, in its absence, be prime candidates for planting. Results of trials in Lesotho show, inter alia, that for some eucalypts resistance to the beetle can be correlated with the latitude of tree origin. Recommendations are made for further work to find other natural control agents, to examine South African trials for evidence which may confirm and strengthen the Lesotho findings and to thoroughly investigate the taxonomy of the eucalypts.
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High levels of insect damage on Eucalyptus have been noted but not quantified in previous literature. We present estimates of leaf damage for 44 Eucalyptus species from a variety of habitats. Overall, an average of 15% of expanded leaf area was missing. While some species were generally lightly grazed, others, especially those in more mesic. higher altitude communities, usually sustained much heavier leaf damage. In the age and size classes, communities and years that we sampled, the overall levels of damage to eucalypts were higher than chronic damage levels reported for north temperate communities. We also suggest a simple method for rapidly estimating the proportion of leaf area missing from trees.
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Manual defoliation of saplings of Jarrah (Eucalyptus marginata), using 12 different combinations of frequency and intensity, reduced stem diameter growth. Growth loss was a linear function of the severity of defoliation. Slight defoliation did not stimulate stem growth. More frequent defoliations of low intensity reduced growth more than less frequent defoliations of higher intensity.
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"Part I reviews progress at the regional level. This section was developed from six regional reports prepared for discussion in 2006. Part II presents selected issues in the forest sector, addressing the latest developments in 18 topics of interest to forestry."
Reperti biologici su Gonipterus scutellatus Gyll. (Col. Curculionidae) infestante gli eucalipti della Riviera Ligure
  • A Arzone
  • F Meotto
Arzone, A. and Meotto, F. 1978 Reperti biologici su Gonipterus scutellatus Gyll. (Col. Curculionidae) infestante gli eucalipti della Riviera Ligure. Redia 61, 205–222