Biology and natural enemies of spotted ash looper, Abraxas pantaria (Lepidoptera, Geometridae) in Krka National Park

Background and Purpose: Spotted ash looper (Abraxas pantaria) is a forest present in Krka National Park, Croatia with occasional mass occurrence. The caterpillars of this pest have completely defoliated leaves of Narrow-leafed ash (Fraxinus angustifolia) in the upper flow of river Krka in the period from 2008–2010. We have researched the biology of spotted ash looper which is first comprehensive study of this pest in Croatia. Materials and Methods: The research of spotted ash looper included field trials through all the years and laboratory experiments. Caterpillars were reared and daily weighted in laboratory. Fresh and dry Narrow-leafed ash leaves have beenweighted and factor of drymatter in leaves defined. For each individual sex, moment of onset of particular larval instar, prepupa, pupa and butterfly was noted in order to identify the duration of each stage and possible differences. Duration of larval stages and consummation of food were analysed separately by gender. A total of 200 pupae of spotted ash looperwere transferred to the laboratory for the identification of natural enemies. Each pupa was placed in a separate glass tube and incubated in laboratory. Results and Conclusions: Our results show biology of this pest in Croatia. Caterpillars feed on Narrow-leafed ash and have not been found on Manna ash (Fraxinus ornus). They have moulted only 3 times and pass through 4 larval instars in laboratory conditions. Average caterpillars of 4th larval instar gained their maximum growth on the 4th day from the beginning of that stage andmaximumweight on the 8th day, three days before entering the prepupal stage. The difference betweenmales and females starts to develop during the 4th larval instar when females consume significantly more food, gain significantly more weight and form significantly heavier pupae. The average 4th larval instar consumes between 0.3329 and 0.3673 g of fresh leaf. Research shows that number of pupae diapauses during the winter,while some of themhave no diapause. This indicates that the pest has at least two generations a year, which was also shown by observations in the field. Pathogen fungus Beauveria bassiana, parasitoids Pales pavida, Cratichneumon cf. fabricator F. and unidentified species from the genus Coelichneumon were natural enemies found in pupae. Beauveria bassiana as a pupal pathogen plays an important role as the most important natural enemy and the existence of its alternative host, ash weevil (Stereonychus fraxini)which occupies the same overwintering niche is also important

ORIENTAL CHESTNUT GALL WASP (DRYOCOSMUS KURIPHILUS) IN CROATIA

U radu je prikazano istraživanje biologije, rasprostranjenosti, intenziteta zaraze i prognoza daljnjeg širenja kestenove ose šiškarice (Dryocosmus kuriphilus) u Hrvatskoj. Kestenova osa šiškarica prvi je put u Hrvatskoj pronađena 2010. godine, a u 2011. nađena je na 12 lokaliteta u 6 županija. Na temelju rezultata istraživanja napravljena je karta rasprostranjenosti kestenove ose šiškarice u Hrvatskoj u 2011. godini. Tijekom istraživanja utvrđeno je da osa ima jednu generaciju godišnje i da se područje rasprostranjenosti kestenove ose šiškarice proširilo u odnosu na lokalitete njezina prvog nalaza 2010. godine. Istraživanjem su utvrđeni i intenziteti zaraze na svim lokalitetima na kojima je ovaj štetnik nađen, a intenzitet zaraze (kategorija 3) bio je najveći na lokalitetima na području Zagreba. Tijekom sljedećih godina može se očekivati širenje kestenove ose šiškarice na nove lokalitete u sastojinama pitomoga kestena na području cijele Hrvatske.The aim of this research was to give an overview of the biology of oriental chestnut gall wasp (Dryocosmus kuriphilus), find the sites where it is present, estimate infection rates and prognose its future spread in sweet chestnut stands in Croatia. Oriental sweet chestnut gall wasp was first recorded in Croatia in 2010, and in 2011. it had spread to new localities. The wasp has one generation per year. The infection rates on all sites was estimated and the highest infection rate was in the Zagreb area. The spread forecast for Croatia for the following years is given. Intensive spread can be expected in all areas where sweet chestnut is grown

First record of Phyllonorycter issikii and distribution of invasive leafminer species from the family gracillariidae in Croatia

Tijekom 20. stoljeća u Europi je došlo do unašanja i naglog širenja nekoliko novih vrsta lisnih minera iz porodice Gracillariidae Lepidoptera) koji su svoj areal pro{irili i na Hrvatsku. U radu su opisane biolo{ke, dijagnostičke karakteristike i rasprostranjenost invazivnih vrsta lisnih minera u fauni Hrvatske: Cameraria ohridella, Phyllonorycter issikii, Phyllonorycter leucographella, Phyllonorycter robiniella, Phyllonorycter platani, Parectopa robiniella. Ovim istraživanjem prvi puta je zabilje`ena pojava lipinog lisnog minera Phyllonorycter issikii u Hrvatskoj. Rasprostranjenje ovih vrsta u Hrvatskoj kao i njihov intenzitet pojave u novom staništu nije nogo odudaralo od uzorka rasprostranjenja i intenziteta pojava u drugim europskim zemljama.Several new species of leafminers from the family Gracillariidae (Lepidoptera) have been introduced to Europe where they have spread very quickly. The same situation happend in Croatia. In this paper distribution, some biological and diagnostic characteristics of new, invasive species in the Croatian leafminer fauna are described: Cameraria ohridella, Phyllonorycter issikii, Phyllonorycter leucographella, Phyllonorycter robiniella, Phyllonorycter platani, Parectopa robiniella. The results of this research present the first record of Phyllonorycter issikii in Croatia. Spread of these species in Croatia and their intensity of occurence has been very similar to the same pattern of spread and occurence in other Europaean countries

First record of Elm Sawfly (Aproceros leucopoda), new Invasive Species in Croatia

Brijestova osa listarica (Aproceros leucopoda; Hymenoptera, Argidae) je nova invazivna vrsta koja se širi Europom. Porijeklom je iz Japana, a prvi nalaz u Europi zabilježen je 2003. U članku se daje prikaz biologije i štetnosti brijestove ose listarice, lokaliteti prvog nalaza i prognozira se njezino širenje i štete u Hrvatskoj. Potencijalni domaćini u Europi su sve autohtone i alohtone vrste brijesta i njihovi kultivari. Vrsta ima četiri generacije godišnje, razmnožava se partenogenezom, a ličinke stvaraju tipične i lako prepoznatljive tragove na listu, karakteristični cik-cak uzorak. One imaju sposobnost potpuno obrstiti brijestova stabla. Brijestova osa listarica je prvi puta u Hrvatskoj nađena 2011. godine na nekoliko lokaliteta, ali ni na jednom nije došlo do značajnije defolijacije. Ova osa listarica može se smatrati invazivnom vrstom u Hrvatskoj, pa se očekuje njezino širenje u cijeloj Hrvatskoj, povećanje gustoće populacije i štete na brijestovim stablima.An invasive sawfly (Aproceros leucopoda; Hymenoptera, Argidae) has been attacking elms (Ulmus sp.) in Europe. It orginates from Japan and has been first recorded in Europe in 2003. In the paper the occurrence of A. leucopoda in Croatia is reported for the first time and prognosis of future dispersal and damages is given. Potential host plants of A. leucopoda are all native and introduced elm species in Europe. The sawfly has up to 4 generations per year and parthenogenetic reproduction, After six larval instars, eonymphs make loosely spun cocoons on the leaves (Figure 3 ). Adults (Figure 4) lay eggs along leaf margins. Young larvae (Figure 5) make distinctive zigzag feeding tracks on leaves (Figure 1 ), older larval instars devour the whole leaf and only midveins are left (Figure 2 ). The larve can completely defoliate elm trees which was the case in Japan, Hungary, Italy, Poland and Romania. A. leucopoda was first recorded in Croatia in 2011 on several locations (Table 1, Figure 6). On the leaves a tipical zigzag feeding tracks were recorded, larvae and cocoons were found and adults were raised from the colected cocoons. The species was identified with the help od the key in Blank et al. (2010). The number of generations per year was not determined. The damage on the elm trees in Croatia was not severe, no defoliation was observed and only single leaves were completely consumed. A. leucopoda can be considered as invasive species in Europe and Croatia, it can be expected that the sawfly will disperse to other parts of Croatia (to forests and urban trees) in the coming years. The sawfly will disperse actively (females are strong flyers) and passively (with traded material and vehicles). Complete defoliation of elm trees in Croatia can not be excluded in the coming years

Further Spread of Corythucha arcuata (Hemiptera; Tingidae) in Croatia

Corythucha arcuata (Hemiptera; Tingidae), i.e. oak bug is an invasive alien species from North America that has rapidly spread in Europe. It was first reported in Croatia in 2013, and in the following years it has spread rapidly toward the west of the continental part of the country, infesting 200,000 ha of Quercus robur L. forest stands. Oak lace bug causes losses in chlorophyll, which has a negative influence on photosynthesis and transpiration activity, as well as on the health status of oak trees. We conducted our study on two sites in the Mediterranean region in Istria, Croatia, where infestation with oak lace bug has not been recorded. Results showed new records of oak lace bug in Istria. Q. pubescens Willd. is the dominant tree species in Sub-Mediterranean forests in Istria, so it will be interesting to follow the spread and preferences of oak lace bug for Q. robur and Q. pubescens in Istria, as well as in other coastal Q. pubescens and Q. ilex L. forests in Croatia. We assume that the negative influence of oak lace bug coupled with other biotic and abiotic stressors in the Mediterranean region will probably have some influence on the health status of oak trees