DIGITALNA ARHIVA ŠUMARSKOG LISTA
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|ŠUMARSKI LIST 5-6/2013 str. 39 <-- 39 --> PDF|
instar or older) that are susceptible to E. maimaiga. The relative proportion of larvae in fourth instar or older ranged from 25.0–72.7% (K/C1, T/C1), and between 85.7% and 95.9% (K/C2, T/C2).
High mortality of gypsy moth larvae was recorded during the laboratory rearing, 88.6–89.3% (K/C1, K/C2), and 36.4–51.0% (TC1, TC2) (Table). All larvae collected in Meses Thermes developed successfully to the imago stage.
Microscopic analysis of the gypsy moth larvae revealed that 78.6% (KC2) were infected with E. maimaiga (Table 1). In three samples (KC1, TC1, TC2) no spores of the pathogen were detected, although dead larvae showed typical symptoms of fungal infection – intact carcasses that were not degraded. Analyses did not indicate the presence of other fungal species or microsporidia.
Studies in FYROM – Istraživanja u Republici Makedoniji
A total of 142 gypsy moth caterpillars were collected and examined in all three sites in FYROM (Table 1). Gypsy moth larval development was the most advanced in Toplica and fourth to sixth instar larvae constituted 81.5% of the population, followed by the larvae from Belovodica (65.3%) and Krushevo (41.6%).
During laboratory rearing of the larvae 16.7–87.8% of all larvae died (Table 1). The carcasses showed typical symptoms of fungal infection and microscopic analysis showed that E. maimaiga occurred in all three localities from FYROM (Table 1).
The results of this study have shown that E. maimaiga has expanded its range. Kidaris, Greece, where E. maimaiga occurred, is located in close proximity to the border with Bulgaria (7 km). The establishment of the pathogen in this site was expected because a strong epizootic occurred 30 km north in Kremen vill., Kirkovo State Forestry, Bulgaria in 2005 (Pilarska et al. 2006; Georgiev et al. 2010). The Macedonian sites Toplica, Belovodica and Krushevo are located 130–170 km from the nearest known site of E. maimaiga natural occurrence in Karlanovo vill. in Southwestern Bulgaria (Georgiev et al. 2011). The establishment of E. maimaiga at such distances, and finding the fungus in the European part of Turkey (Georgiev et al. 2012a) and Serbia where two strong outbreaks of gypsy moth (Tabaković-Tošić et al. 2012) are apparently suppressed demonstrates evidence that the E. maimaiga has expanded its range. It should be noted that E. maimaiga has been documented to spread by natural means more than 100 km in one season (Elkinton et al. 1991).
Additional evidence of E. maimaiga range extension is the establishment of the pathogen in 2005 in Dusheti region of Georgia (Kereselidze et al. 2011). Molecular analyses of the strain did not allow identification of the origin of E. maimaiga in Georgia, but it is known that airborne conidia are distributed by wind, facilitating rapid spread of the fungus at long distances (Hajek 1999; Hajek et al. 1999). The closest