The North American oak lace bug feeds on leaves of ‘white oaks” in its native range. In Europe, it was first discovered in northern Italy in 2000. In recent years, it has subsequently spread rapidly ...and population outbreaks have been observed in several European countries. In the present study, we summarize the steps of its expansion.
To predict its potential host range, we checked 48 oak species in 20 sentinel gardens in seven countries between 2013 and 2018.
In total, 27 oak species were recorded as suitable hosts; 13 of them are globally new ones, 23 out of the 29 in section Quercus (∼ white oaks, an intrageneric taxonomic unit within genus Quercus), including Asian oaks, native to Japan, Korea and China, and four out of five in section Cerris (another intrageneric unit of the same genus), were accepted as hosts. None of the species in section Lobatae (red oaks) or in the Ilex group was accepted.
Host records were also collected in forest stands of 10 countries. We found 11 oak species that were infested. Outbreak populations were most commonly found on Quercus robur, Quercus frainetto, Quercus petraea and Quercus cerris, comprising widespread and outstandingly important oaks species in Europe.
Based on our findings, we conclude that suitable hosts for oak lace bug are present in most of Europe and Asia. This means that a lack of hosts will likely not restrict further range expansion.
Isolates that resemble Dothiorella (Botryosphaeriaceae, Ascomycota) species were isolated from dead twigs, asymptomatic and necrotized bark of European hop hornbeam (Ostrya carpinifolia Scop.), ...Eurasian smoke tree (Cotinus coggygria Scop.) and common juniper (Juniperus communis L.) growing in western Slovenia and northern Italy. They were identified based on anamorph morphology and phylogenetic analyses of the ITS rDNA and EF-1α sequences, and previously designated as Dothiorella sp. A, B and C. This study has clarified the identity of these species by comparing them with other Dothiorella species known from culture based on gene sequence data, as well as morphological characters of the anamorphs. The phylogenetic results revealed three species, Dothiorella iberica, Dothiorella parva, and a Dothiorella sp. Isolates identified in the phylogenetic analyses as D. parva differed from the original description of this species and are thus described here based on the anamorph morphology. Isolates of D. parva were identified from O. carpinifolia in western Slovenia and northern Italy, and C. coggygria western Slovenia, and coexist with Dothiorella sp. on O. carpinifolia in northern Italy. Dothiorella iberica was identified on J. communis in western Slovenia, thus expanding the geographic range of this species. This is the first record of D. parva from these hosts and countries. Our results indicate that these Dothiorella species occur widely across the Mediterranean region, and on a variety of hosts.
O nalazu hrastove mrežaste stjenice (
Corythucha arcuata
) u parku dvorca Lužnica kod Zaprešića, Hrvatska, 6 km od slovenske granice, obavijestio nas je prof. Boris Hrašovec sa Šumarskog fakulteta ...Sveučilišta u Zagrebu u jesen 2016. godine. 17. 11. 2016 obavili smo potragu za štetnikom na sedam lokacijama u jugoistočnoj Sloveniji (Mokrice, Obrežje, Rigonce, Dobova, Mostec, Zakot i Bukošek). Pričvršćeno i djelomično zeleno lišće, kao i otpalo lišće
Quercus robur
je bilo na terenu pomno pregledano i sumnjivi uzorci su stavljeni u plastične vrećice i donijeti u laboratorij za daljnju analizu. Morfološka identifikacija je provedena na uzorku jajnih grupa na donjoj strani lišća i svlakova ličinki (exuviae) koje su bile prisutni na otpalom lišću
Q. robur
. Izvršeno je mjerenje broja jaja u 9 jajnih grupa i dužina i širina 30 jajnih čahura. Jajne ljuske (čahure) i svlakovi ličinaka na otpalom lišću
Quercus robur
bile su na pretraženom području nađene samo u hrastovoj šumi kod sela Zakot u blizini Brežica (E, 45°54’48“ N), koji je 14 km od najbližjeg nalaza u Hrvatskoj kod dvorca Lužnica. Jajne grupe sadržale su od 12 do 61 jajnih čahura. Jajne čahure su bile vretenastog oblika i crna s apikalnim otvorom i rubnim zadebeljenjem, duge 560 μm (475-596 μm) i široke 196 μm (183-196 μm). Ličinke su bile uglavnom tamne sa prozirnim žućkastim dijelovima na obje strane tijela. Imale su brojne bodlje. Brojne katranasto crne mrlje izmeta (faeces) hrastove mrežaste stjenice nalazile su se ravnomjerno na donjoj površini hrastovog lišća na kojem su bile prisutne jajne čahure i svlakovi ličinki.
C. arcuata
najvjerovatnije se proširila u Sloveniju iz Hrvatske, gdje je bila opažena kod dvorca Lužnica, ili kao autostoper sa željezničkom transportom, jer sjevernu granicu šume kod sela Zakot predstavlja željeznička pruga koja vodi od balkanske regije prema srednjoj Europi. U početku srpnja 2017. ustanovili smo namnoženje
C
.
arcuata
na lokaciji prvog nalaza i širjenje vrste na područje Krakovske hrastove šume, udaljeno 17 km zračne linije od sela Zakot.
Here we report the discovery of
Corythucha arcuata
in Slovenia in autumn 2016. Egg shells and molts of oak lace bug were found on the fallen leaves of
Quercus robur
in an oak forest in the village of Zakot near Brežice in the southeastern part of Slovenia.
C
.
arcuata
most likely spread to Slovenia from Croatia, where it was previously reported from the park at Lužnica Castle near Zaprešić, 14 km from the find in Slovenia, or as a hitchhiker on rail traffic running along the northern edge of infested forest. Further spread of
C. arcuata
to Krakovo oak forest was detected in the beginning of July 2017.
Usporedili smo izvedbu dviju metoda praćenja zdravstvenog stanja urbanih šuma. Prva se temelji na sustavnoj mreži (ISM), a druga na nelinearnim transektima (UFMO). Obje metode testirane su tijekom ...srpnja i kolovoza 2013. u urbanoj šumi Rožnik u općini Ljubljana (MOL). Procijenili smo stanje krošanja i štetnih čimbenika na 15 ISM ploha, istražujući površinu od 92 a u 1.640 minuta. Metoda UFMO korištena je za ispitivanje površine od 518 a za 1.700 minuta. Performanse ISM-a i UFMO metoda bile su 17,8 min/a odnosno 3,28 min/a. U skladu s mjerenjem performansi vremena/površina, UFMO metoda je provedena 5,4 puta brža od ISM metode. Metoda UFMO zabilježila je 1,5 puta više štetnih čimbenika po satu, 2,7 puta više stabala po satu i 13,4 puta više mrtvih stabala po satu. Također je predloženo 7,0 puta više mjera upravljanja po satu. Međutim, gustoća prikupljenih podataka bila je 7,1 puta veća za ISM metodu. Prema odabranim mjernim pokazateljima, ukupna uspješnost metode UFMO premašila je ISM metodu u svim odabranim mjerama uspješnosti izraženim u relativnom vremenu, osim količine prikupljenih podataka. Zaključujemo da, za isti trošak uzorkovanja, ISM pristup proizvodi nepristranu, ali nepreciznu procjenu ukupnog zdravlja šuma, dok metoda UFMO daje pristranu ali precizniju procjenu. Raspravljamo o mogućim poboljšanjima i daljnjim ograničenjima UFMO metode s naglaskom na razlike između dviju metoda praćenja zdravstvenog stanja šuma. Zaključujemo da se metoda praćenja ISM može dopuniti metodom mjerenja UFMO kako bi se iskoristile potencijalne prednosti kombiniranja oba pristupa.
We compared the performance of two methods for monitoring urban forest health. The first was based on a systematic grid (ISM), and the second on non-linear transects (UFMO). Both methods were tested during July and August 2013 in the Rožnik urban forest in the Municipality of Ljubljana (MOL). We assessed crown condition and damaging agents on 15 ISM plots, surveying an area of 92 a (are = 100 m2) in 1,640 minutes. By comparison, the UFMO method was used to survey an area of 518 a in 1,700 minutes. The performance of the ISM and the UFMO methods was 17.8 min/a and 3.28 min/a, respectively. According to the time/area performance measure, the UFMO method performed 5.4 times better than the ISM method. The UFMO method recorded 1.5 times more damaging agents per hour, 2.7 times more trees per hour, and 13.4 times more dead standing trees per hour. It also suggested 7.0 times more management measures per hour. However, the density of the data gathered was 7.1 times higher for the ISM method. According to the chosen comparison measures, the overall performance of the UFMO method exceeded the ISM method in all chosen performance measures expressed in relative time except the amount of data gathered. We conclude that, for the same sampling cost, the ISM approach produces an unbiased, but imprecise, estimate of overall forest health, while the UFMO method produces a biased, but more precise, estimate. We discuss possible improvements and further limitations of the UFMO method with an emphasis on the differences between the two methods of monitoring and surveying forest health. We conclude, that the ISM monitoring method can be supplemented with the UFMO surveying method to capitalize on the potential synergies of combining both approaches.
The attractiveness of different semio-chemicals to potential vectors of the phytoparasitic nematode
Bursaphelenchus xylophilus
was investigated in conifer forests in Slovenia. From 2007 to 2009, the ...presence of xylophagous beetles in
Pinus nigra
,
P. sylvestris
,
P. halepensis
,
Picea abies
and
Abies alba
stands was assessed at eight locations. Insects were collected at 1-month intervals during the growing season using four cross vane traps per location with a collecting container with propylene glycol and attractants (ethanol+α-pinene, Pheroprax® and Gallowit®). The trapped insects represented 24 families of the order Coleoptera, and we identified 94 species. The most numerous group was the weevil subfamily Scolytinae (76.55% of all insects collected), followed by the family Cerambycidae (8.12%), and the weevil subfamily Curculioninae (1.67%). With regard to species number, the most frequent wood-borers were Cerambycidae (24 taxa), Scolytinae (12 species) and Buprestidae (8 species). The most abundant species was
Spondylis buprestoides
, followed by
Arhopalus rusticus
,
Monochamus galloprovincialis
and
Arhopalus ferus.
At all locations, the largest catch of Cerambycidae occurred in July. The most effective attractant was ethanol+α-pinene, followed by Gallowit®; the least effective attractant was Pheroprax®. Among
Monochamus
species,
M. galloprovincialis
represented 17.54%,
M. sutor
0.09% and
M. sartor
0.04% of the long-horned beetles collected.
Monochamus
individuals were most numerous in the
P. nigra
stand and were attracted in the greatest numbers by Gallowit®, followed by ethanol+α-pinene. The cerambycid catch was highly correlated with the catch of non-target bark beetle predators (Cleridae, Staphylinidae, Histeridae, Trogositidae, Nitidulidae, Rhizophagidae) in the traps.
The composition and variability of the terpenes and their derivatives isolated from the needles of a representative pool of 114 adult trees originating from four natural populations of dwarf mountain ...pine (Pinus mugo Turra) from the Julian Alps were investigated by GC‐FID and GC/MS analyses. In total, 54 of the 57 detected essential‐oil components were identified. Among the different compound classes present in the essential oils, the chief constituents belonged to the monoterpenes, comprising an average content of 79.67% of the total oil composition (74.80% of monoterpene hydrocarbons and 4.87% of oxygenated monoterpenes). Sesquiterpenes were present in smaller amounts (average content of 19.02%), out of which 16.39% were sesquiterpene hydrocarbons and 2.62% oxygenated sesquiterpenes. The most abundant components in the needle essential oils were the monoterpenes δ‐car‐3‐ene, β‐phellandrene, α‐pinene, β‐myrcene, and β‐pinene and the sesquiterpene β‐caryophyllene. From the total data set of 57 detected compounds, 40 were selected for principal‐component analysis (PCA), discriminant analysis (DA), and cluster analysis (CA). The overlap tendency of the four populations suggested by PCA, was as well observed by DA. CA also demonstrated similarity among the populations, which was the highest between Populations I and II.
Ash dieback is caused by a highly pathogenic fungus Hymenoscyphus pseudoalbidus (anamorph Chalara fraxinea). Possibilities for disease control are limited, and treatment of fallen leaf debris to ...prevent sporulation of the pathogen is one of the possible options to control the disease. In some cases chemical treatments could be used, but data on effective chemical agents for control of the ash dieback are lacking. The purpose of this study was to examine the effect of different chemical fungicides and urea on the pathogen. Out of eight tested fungicides, mycelial growth in Petri plates as well as development of H. pseudoalbidus apothecia on ash leaf petioles were most efficiently inhibited by carbendazim. Urea also proved to be effective in prevention of apothecial formation. In addition to inhibition of the pathogen, urea accelerates the degradation of treated leaf debris. Therefore, the use of urea for treatment of infected ash leaf debris could be more effective than the use of fungicides and also more environmentally acceptable.
PDF
