The flight of the Cameraria ohridella population in the city of Timisoara, Romania

Fora C.G.1*, Lauer K.F.2, Fora Alina1, Damianov Snejana3, Moatăr Mihaela1

1Faculty of Horticulture and Forestry Timisoara; 2University of Applied Sciences Weihenstephan; 3Faculty of Agriculture Timisoara

*Corresponding author. Email: [email protected]

Abstract The aim of this paper is to fallow the flight dynamics of horse Key words chestnut leaf-miner Cameraria ohridella in the parks of Timisoara city. Following the observations made by using of the sticky tetra-trap baited with Cameraria ohridella, flight, synthetic pheromone AtraCam, it can be concluded that the harmful insect Timisoara, parks has three flights over all growing season, since middle of April (with ornamental chestnut flowering Aesculus hippocastanum) to the end of September. Maximum numbers of captured adults from one flight to another have an exponentially growing. During the research it is observed the preference of insect for solar heat in terms of flight and as the place chosen by the females to laying eggs. Thus, the preference for a part of the tree crown exposed to heat are obvious, especially at the first flight (over 83% of "mines" is on exhibition southern, western and eastern). At next flights due the increasing of air temperature the differences are not significant.

After Perju et al. (2009) the insect is only slightly over 16% of the exhibition leafs on originally from Asia. Extending species after Rakosy northern. (2009) in Europe began from two distinct expansion centers namely in Macedonia, where she was seen in Materials and Methods 1984 and Austria in 1989. Hence, due to she’s biology and due the low number of predators and parasitoids, is The flight monitoring of the horse chestnut extending rapidly across Europe in next years. The leaf-miner was made in two parks from Timisoara city main host plant of the moth is Aesculus where ornamental chestnut is in lines, in Axente Sever hippocastanum. After Kukula and Hurej (2004) the Square Park and USAMVBT Park. moth can be found, in a small extent, on the hybrid To monitoring, was used sticky tetra-trap Aesculus x carnea to. The researches made by Freie et baited with the synthetic pheromone AtraCam, three al., published in 2004, show that the moth larvae do for each zone, on different trees, located at a distance not survive on this hybrid, but a very powerful attack of 20-30 meters between them. on the leafs “almost 100%” was observed on Acer Install the traps was made early in April, pseudoplatanus and Acer platanoides. before the beginning of the flight, on tree branches at First flight of horse chestnut leaf-miner in the the base of crown of host trees (figure 1). Periodically, parks of Timisoara, the specimens from the generation throughout the all growth seasons were made that overwintering in the pupa stage, starting in the observations of caught biological material (figure 2). middle of April, the second in the second decade of At every observation the trap was cleaned up May and the third in the second decade of July, earlier to prevent decreasing of the attractiveness of than some populations in Bulgaria observed by pheromone baits. Also, once of 30 days the baits was Subchev et al. (2004) and relatively similar to some changed with other fresh ones. populations from Hungary. To underline the preference of the moth for Knowing that the attack begins on leafs from heat, after the first and the second flight, it was the lower part of tree crown [3] and then spreads harvested from the same tree 25 leafs aiming at throughout in all tree crown, I made observations on cardinal points, in total 100 leaves for every flight. The the species preference for solar heat. Thus, it shows the mines were taken into account. For third flight the number of the mines and arrangement of them on leafs, counting could not be done because many of mines predominantly after the first flight, on southern immerged causing premature leafs drying. exposition, western and eastern of the tree crown and

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Fig.1. Sticky tetra-trap baited with AtraCam

Fig.2. Caught moths

Obtained results The second flight began in the second decade of May, covers a longer period (63 days) and knows a During the all growing season the horse maximum between June 17 and July 7. The maximum chestnut leaf-miner had three flights (figure 3 and 4), number of moths caught in a race was 487. Intensive which has be taken in 156 days. flight takes place throughout the day with a maximum The first flight began in the second decade of at noon and takes place in the entire crown. April and lasted 26 days. Maximum first flight was The same it is the third flight and began from shortly after the beginning of this flight during 20-29 the second decade of July, over 67 days, with a peak April. The maximum number of moths caught in a trap between July 30 and August 15. The maximum number was 169. Intensive flight takes place around noon, at of moths caught in a trap was 570. Flight ends in late the crown base level and above the grass. September.

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Flight dynamic

450

400

350

300

250 Trap I Trap II 200 Trap III

Caught moth no.Caught 150

100

50

0 18.04. 20.04. 29.04. 06.05. 13.05. 10.06. 17.06. 24.06. 07.07. 15.07. 30.07. 07.08. 15.08. 21.08. 30.08. 10.09. 15.09. 20.09. Days

Fig.3. Cameraria ohridella flight in Axente Sever Sqare park

Flight dynamic

600

500

400

Trap I 300 Trap II Trap III

Cauth moth no.Cauth 200

100

0 18.04. 20.04. 29.04. 06.05. 13.05. 10.06. 17.06. 24.06. 01.07. 07.07. 15.07. 30.07. 07.08. 15.08. 21.08. 30.08. 10.09. 15.09. 20.09. Days

Fig.4. Cameraria ohridella flight in U.S.A.M.V.B.T. park

The flying of the moths is one agile and exhibition (21 respectively 20%) and finally to the mating occurs on tree crown and tree stems or grass northern (17%). blanket. In the case of the second flight (figure 6) is Immediately after mating females seek the amended in that situation although a preference for most favorable places for oviposition future offspring western and eastern exhibition be kept relatively to ensure the best living conditions. In the case of the constant, the northern exposure almost equals the moth Cameraria ohridella the females lay eggs on leaf southern. Explanation becomes from the fact that surfaces which are most exposed to solar heat, a during the second flight the air temperature become phenomenon clearly visible at first flight. In the order higher and the differences of expose is canceled. of preference (figure 5), resulting from observations, it Standardize the percentages are virtually throughout can be said that the southern exhibition is most crown. favorable (42%), followed by eastern and western

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Mines no. distribution on lief 06.05.

Vest Nord 20% 17%

Est 21%

Sud 42%

Fig.5. Distribution in 06 May

Mines no. distribution on lief 07.07.

Vest Nord 25% 24%

Est Sud 23% 28%

Fig.6. Distribution in 07 July

In climatic and attack conditions of the year - the third flight begins in the second decade of 2009, many of the defoliated trees have flowering July with a peak between July 30 and August twice in September. 15; - the end of the flight is in late of September; Conclusions - the flight of the moths is agile one, in the spring is on the base of the tree crown and Following the researches made in 2009 in two over the grass and in summer in entire crown parks from Timisoara city with Aesculus with a peak around noon; hippocastanum, regarding the flight of the horse - the moth prefer the sun heat, the southern chestnut leaf-miner Cameraria ohridella flight, we expoisure. reached the next conclusions: References - the moth has three flights on year, over 156 days; 1. Freise J., Heitland W., Sturm A., 2004, - first flight begins in the second decade of Assessing the host plant range of the horse- April and have a maximum during the period chestnut leaf miner, Cameraria ohridella 20-29 April; Deschka & Dimić (Lepidoptera: - the second flight beginning in the second Gracillariidae) - a hint to the origin of the decade of May and have a maximum between moth?, 1st International Cameraria June 17 and July 7; Symposium:Cameraria ohridella and other leaf-miners in Europe, Prague, pp. 10

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2. Kukuła-Młynarczyk A. and Hurej M., 2004, listed and unlisted with plant protection Infestation of white (Aesculus hippocastanum quarantine status, neobiota in Romania, L.) and red horse chestnut (Aesculus carnea Neobiota din Romania, Presa Universitară H.) by the horse chestnut leafminer in Lower Clujeană, Cluj-Napoca, pg. 114-123 Silesia (Poland), 1st International Cameraria 5. Rakosy L., 2009, Lepidoptera (Butterfly and Symposium: Cameraria ohridella and other Moths), Neobiota din Romania, Presa leaf-miners in Europe, Prague, pp. 21 Universitară Clujeană, Cluj-Napoca, pg. 166- 3. Lupi, D., Jucker, C., 2004, Method to quantify 173 Cameraria ohridella leaf damages on 6. Subchev M., Albena Mircheva, Boyan H., Aesculus hippocastanum using image Rumen T., 2004, Phenology of Cameraria analysis, 1st International Cameraria ohridella Deschka & Dimić (Lepidoptera: Symposium: Cameraria ohridella and other Gracillariidae) in Bulgaria, 1st International leaf-miners in Europe, Prague, pg. 29-31 Cameraria Symposium: Cameraria ohridella 4. Perju T., Bodiş Ilonka, Crişan Mihaela, and other leaf-miners in Europe, Prague, pp. Teodor A., 2009, Phytophagous invertebrates, 40.

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