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ŠUMARSKI LIST 13/2011 str. 123     <-- 123 -->        PDF

M. Pernek, N. Lacković: ULOGAJELOVIH KRIVOZUBIH POTKORNJAKAU SUŠENJU JELE I MOGUĆNOSTI ... Šumarski list – Posebni broj (2011), 114-121


Spaić, I., 1955: Problematika zaštite šuma u NR
Hrvatskoj. Šumarski list 11–12: 440–468.


Ugarković,D., I. Tikvić, Z.Seletković, 2011:
Odnos stanišnih i strukturnih čimbenika prema
odumiranju i ishrani stabala obične jele (Abies
alba Mill.) u Gorskom kotaru (Correlation of
Habitat and Structural Factors with Dieback
and Nutrition of Silver Fir (Abies albaMill.) in
Gorski Kotar).Croatian Journal of Forest Engineering
32(1): 57–71.


Ušćuplić, M., M. Dautbašić, T. Treštić, T.
Nišić, B.Jokanović, E.Selman, O.Mujezinović,
2005: Umiranje jele (Abies alba)
u Bosni i Hercegovini. Akademija nauka i
umjetnosti Bosne i Hercegovine, Sarajevo.


SUMMARY: Silver fir is the most important coniferous species in Croatian
forestry, but in the same time the most threatened whose strong decline occurs
periodically.Recent decline in Croatia was registered in the year 2003, especially
in Lika and Gorski Kotar, with strong attack of fir bark beetles.This
beetle gradation is connected with the three known Pityokteines species in
Croatia: P. curvidens, P. spinidensandP. vorontzowi.The aim of this work
was to determine what impact bark beetles have on the decline of Silver
fir.For this purpose pheromone traps were placed in Litoric (Gorski Kotarmiddle
Croatia), for monitoring through the vegetation periods from 2004to
2010. In addition, in 2007the effectiveness of different trap systems was tested.
The commonly used Theysohn trap with dry container was modified
through locking the container so liquid that was previously put in it couldn’t
efflux. A pheromone mixture named Curviwit ® was used which is used for individuals
baiting of fir bark beetle species Pityokteines curvidens.


The results during the seven year monitoring period show clearly visible
connection between fir bark beetles and fir decline (Figure 1). The largest
catches in pheromone traps were measured between 2005 and 2007,when the
most injured trees were felled in the forests.Most catches, about 94 %, throughout
the year of monitoring occur in April and May (Figure 2 and 3), which
concludes that traps should be placed only in those months. The test results of
dry versus wet traps show that more important catch is achieved by modifying
Theysohn traps to wet traps (Figure 4).


On the basis of calculating the abundance of bark beetles ofP. spinidens
andP. curvidensin the trunk (Table 1) and the use of maximum mortality rates
of 70 %, from previous studies biological potential of these insects was simulated.
One infected 90 year old fir tree is directly threatening 50-60 trees in the
next years.This result demonstrates the enormous potential of the silver fir
bark beetle species. Because of the need to reduce the population of bark beetles,
use of pheromone traps for monitoring should be considered as one action
for effective preventive and sanitary measures in protection of forests.


Key words:Pityokteines spinidens, P. curvidens, P. vorontzowi,Abies
alba, pheromone traps