Az éger állományok új típusú fitoftórás megbetegedésének vizsgálata = Study of new Phytophthora disease in common alder stands

A négy éves kutatási program eredményeként részletesen feltártuk a hazai égerekben előforduló fitoftórás megbetegedés jellegzetességeit, erdőgazdasági jelentőségét. A vizsgálatok tapasztalatai azt mutatják, hogy a hazai égeresekben a fitoftórás fertőzések országszerte megtalálhatóak. Ugyanakkor a beteg fák aránya, a fertőzés intenzitása, a betegség terjedése, a mortalitási értékek nem támasztják alá azt a feltételezést, miszerint az állományok létét veszélyeztetné a betegség megjelenése. A vizsgálatok egyértelműen igazolták a Phytophthora alni patogenitását, míg a többi fitoftóra faj jelentősége kétséges az elhalások kialakulásában. Mindezek mellett azt is megállapítottuk, hogy az esetek többségében a pusztulási folyamat tovább tart, mint négy év. Egyes esetekben a fák képesek a betegséget természetes védekező mechanizmusaik révén legyőzni. Az új típusú fitoftórás betegség országosan jelen van és stabilan állandósult a hazai éger állományokban. Epidémikus megjelenése bármikor bekövetkezhet, de ennek előfeltételeiről egyelőre keveset tudunk. | Characteristics and importance of alder decline caused by Phytophthora in Hungary were studied during 4 years of the project. According to the results of our investigations Phytophthora infections are widespread and occur in all Hungarian alder forests. However the number of infected trees, severity of infections, spreading rate of disease and the tree mortality caused do not support the earlier assumptions that the disease seriously fate of our alder forests. Pathogenity of Phytophthora alni was proven by investigations, but role of other Phytophthora species in alder decline still remain uncertain. The decline ending with death of the infected tree usually takes longer than four years. In some case Phytophthora infected trees can successfully fight of the disease by own natural defence mechanisms. The new type of alder decline caused by Phytophthora is widespread in Hungary and settled in the alder stands. Severe epidemic appearance of Phytophthora alni may occur any time but there is not enough information about its prerequisites

A population dynamical model of Operophtera brumata, L. extended by climatic factors

Setting out from the database of Operophtera brumata, L. in between 1973 and 2000 due to the Light Trap Network in Hungary, we introduce a simple theta-logistic population dynamical model based on endogenous and exogenous factors, only. We create an indicator set from which we can choose some elements with which we can improve the fitting results the most effectively. Than we extend the basic simple model with additive climatic factors. The parameter optimization is based on the minimized root mean square error. The best model is chosen according to the Akaike Information Criterion. Finally we run the calibrated extended model with daily outputs of the regional climate model RegCM3.1, regarding 1961-1990 as reference period and 2021-2050 with 2071-2100 as future predictions. The results of the three time intervals are fitted with Beta distributions and compared statistically. The expected changes are discussed

Két invázív akác-aknázómoly (Parectopa robiniella és Phyllonorycter robiniella) jelentőségének, életmódjának és természetes ellenségeinek vizsgálata = Importance, life history and natural enemies of two invading leaf miners (Parectopa robiniella and Phyllonorycter robiniella) of black locust

A Parectopa robiniella 1983., a Phyllonorycter robiniella 1996. óta van jelen a magyar faunában. Mindkét faj gyorsan terjedt el az országban, sokhelyütt már károkat is okoznak. Az utóbbi 10 év átlagában a Parectopa kártételét 3813, a Phyllonorycter-ét 837 ha-ról jelentették Ellentétben a korábbi várakozásokkal, nem igazolható az aknázott levelek korai lehullása. A Parectopa két-, a Phyllonorycter háromnemzedékes. A Parectopa aknái 2-3 héttel később, kb. június közepén jelennek meg. A Parectopa hernyó magányosan fejlődik, a Phyllonorycter aknában akár 8 lárva is található. A kifejlett Parectopa lárva az avarban, a Phyllonorycter lárvák az aknában bábozódnak. A Phyllonorycter imágóként és bábként, a Parectopa bábként telel. A hazai aknázók parazitoidjai elfogadták a két új fajt. Phyllonorycter-ből 19, Parectopa-ból 12 parazitoid fajt neveltünk. A domináns fajok területenként és évenként különbözőek, de a Pholetesor nanus és az Achysocharoides cilla fajok a legjelentősebbek. A legmagasabb parazitáltság Phyllonorycter-nél 47,6 %, a Parectopa-nál 15,3 % volt, azaz a parazitoidok jelentős szerepet játszanak a szabályzásában. A Phyllonorycter parazitáltsága mindig magasabb volt, mint a Parectopa-é. Ennek okai az eltérő életmód (nemzedékszám, bábozódás helye, stb.), illetve az, hogy amíg Magyarországon 60-nál több Phyllonorycter faj ismert, addig Parectopa (beleértve a P. robiniella-t) csak 2. Ezért a parazitoidok lassabban képesek elfogadni a Parectopa-t, mint a Phyllonorycter-t. | Parectopa robiniella was first found in Hungary in 1983, Phyllonorycter robiniella in 1996. Both spread through the country very fast, becoming abundant at many places. As average of the last 10 years, damage of Parectopa is reported from 3,813, Phyllonorycter from 4,837 ha. We could not prove the early fall of the mined leaves. Parectopa has 2, Phyllonorycter has 3 generations/year. First mines of Parectopa appear 2-3 weeks later than Phyllonorycter mines. Parectopa larvae develop singly, up to 8 larvae of Phyllonorycter can live in 1 mine. Matured Parectopa larvae pupate in the litter, Phyllonorycter larvae within the mine. Phyllonorycter overwinters as adult or pupa, Parectopa as pupa. The native parasitoids accepted the two new hosts. 19 species of parasitoids from Phyllonorycter and 12 from Parectopa were recorded. The dominant species were different in different years/places, but Pholetesor nanus and Achysocharoides cilla were the most important. The highest of parasitism was 47.6% for Phyllonorycter and 15.3% for Parectopa. So parasitoids play significant role in regulation of populations. The rates for Phyllonorycter were always higher than for Parcetopa. Possibly because of the different life history (number of generations, place of pupation, etc.) and also because while more than 60 Phyllonorycter present in Hungary, only 2 Parectopa (incl. P. robiniella). Therefore the parasitoids are probably able to accept and use Phyllonorycter more efficiently than Parectopa

Parasitoid assemblages of two invading black locust leaf miners, Phyllonorycter robiniella and Parectopa robiniella in Hungary

Background and Purpose: Two leaf miners, Parectopa robiniella and Phyllonorycter robiniella (Lepidoptera, Gracillariidae), native to North America, were stablished in Europe. These two invaders provide an excellent opportunity to study the insertion of new species into an existing host-parasitoid community. The following hypotheses were tested: (i) parasitoids attacking the invaders have a wide rather than a narrow host range; (ii) the invading leaf-miner species on black locust are attacked by fewer species of parasitoids than endemic species; (iii) the parasitoid communities attacking invading species are most similar to those attacking endemic leaf-miners with similar ecology; (iv) how the parasitoid communities affect the population dynamics of invaders; (v) what is the difference between the Ph. robiniella and Pa. robiniella parasitoid communities. Materials and Methods: Samples were taken at two sites in pure black locust stands: Gödöllõ (Pest county) and Visonta (Heves county) and in the western part of Hungary: Csorna, Koroncó, Lövõ (Gyõr-Moson-Sopron County). From each sampling site twenty 60 cm long branches were randomly cut and the first top 15 leaveswere checked on each branch: the number of leaflets per leaves and the number of mines per each leaflet were counted. 300 mines of each leaf-miner species were chosen randomly from 10 trees in different canopy levels and were carried to the laboratory for further individual rearing. Results and Conclusions: All the parasitoid species reared from these two leaf-miners are generalists – common and abundant species on different lepidopteran leaf-miners associated with oaks and other woody plants. In both, Ph. robiniella and Pa. robiniella, the same dominant species of parasitoidswere reared. In Ph. robiniella the parasitoid species richness was slightly higher than in Pa. robiniella. The two invading leaf-miners, Ph. robiniella and Pa. robiniella, recruited a parasitoid community of nearly the same size as native Phyllonorycter species on oaks and this process of shifting onto new hosts was quite rapidly, during 10–20 years. The parasitoid communities of Parectopa are simpler than in Phyllonorycter, which is probably due to differentmine structure and ecology of the two invading hosts

Parasitoid assemblages of two invading black locust leaf miners, Phyllonorycter robiniella and Parectopa robiniella in Hungary

Background and Purpose: Two leaf miners, Parectopa robiniella and Phyllonorycter robiniella (Lepidoptera, Gracillariidae), native to North America, were stablished in Europe. These two invaders provide an excellent opportunity to study the insertion of new species into an existing host-parasitoid community. The following hypotheses were tested: (i) parasitoids attacking the invaders have a wide rather than a narrow host range; (ii) the invading leaf-miner species on black locust are attacked by fewer species of parasitoids than endemic species; (iii) the parasitoid communities attacking invading species are most similar to those attacking endemic leaf-miners with similar ecology; (iv) how the parasitoid communities affect the population dynamics of invaders; (v) what is the difference between the Ph. robiniella and Pa. robiniella parasitoid communities. Materials and Methods: Samples were taken at two sites in pure black locust stands: Gödöllõ (Pest county) and Visonta (Heves county) and in the western part of Hungary: Csorna, Koroncó, Lövõ (Gyõr-Moson-Sopron County). From each sampling site twenty 60 cm long branches were randomly cut and the first top 15 leaveswere checked on each branch: the number of leaflets per leaves and the number of mines per each leaflet were counted. 300 mines of each leaf-miner species were chosen randomly from 10 trees in different canopy levels and were carried to the laboratory for further individual rearing. Results and Conclusions: All the parasitoid species reared from these two leaf-miners are generalists – common and abundant species on different lepidopteran leaf-miners associated with oaks and other woody plants. In both, Ph. robiniella and Pa. robiniella, the same dominant species of parasitoidswere reared. In Ph. robiniella the parasitoid species richness was slightly higher than in Pa. robiniella. The two invading leaf-miners, Ph. robiniella and Pa. robiniella, recruited a parasitoid community of nearly the same size as native Phyllonorycter species on oaks and this process of shifting onto new hosts was quite rapidly, during 10–20 years. The parasitoid communities of Parectopa are simpler than in Phyllonorycter, which is probably due to differentmine structure and ecology of the two invading hosts