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ŠUMARSKI LIST 11-12/2007 str. 46     <-- 46 -->        PDF

V. Jurjević, J. Margaletić, M. Glavaš, B. Hrašovec, D. Diminić: ANALIZA SUZBIJANJA GUBARA ... Šumarski list br. 11–12, CXXXI (2007), 539-548
the lack of fruit. In the case of total defoliation, the growth interval can be
reduced up to 30%. In the event that the leaves appearing after defoliation are
destroyed by the powdery oak mildew (Microsphaera alphitoides Griff. et
Maubl.), it has been established that the reduction of the growth interval is
even greater, thereby creating the conditions for massive forest drying.


Forest protection tasks, one of the core activities of the state-held company
Croatian Forests d.o.o. Zagreb, are organized in a three tier system (Direction,
District forest management, forest district), in which each level has clearly
defined tasks as prescribed by the Forests Act, the Plant Protection Act,
the Fire Protection Act, general company acts and a series of other laws and
by-laws.


Assessments of the abundance of the gypsy moth in the forests of Croatia
have been carried out by determining the abundance of egg masses along a
diagonal line laid down in the forest stand. The intensity of representation is
divided into five degrees depending on the percentage of trees on which egg
masses are recorded. In 2002, the presence of the gypsy moth was recorded of
varying intensity on 58,458 ha of forest, in 2003 on 84,409.56 ha, and in 2004
on 149,153.39 ha. Based on the abundance assessment for autumn 2004, the
assumption was that the abundance of this species was expected to rise in
spring 2005, and protection measures were organized on an overall area of
31,304 ha of forests managed by the District Forest Managements of Vinkovci,
Osijek, Našice, Zagreb, Sisak and Nova Gradiška. Controlling actions
included the following activities: determining the areas for control, determining
the method of control, preparing maps with areas where the pest was
recorded, determining the type of insecticide to be used and procuring the
same, determining the airport to be used, ensuring a sufficient number of
transport vehicles for the supply of insecticide and personnel to the airport
and informing the public (particularly bee-keepers) of the time of implementing
the activities.


The decision to use certain substances was made based on the following criteria:
percentage of trees where egg batches were recorded (intensity of the
“attack”), status of individual stands (whether they lie in a protected area or
not), the available quantity of all types of protective measures, meteorological
conditions, technical aircraft equipment and a study of caterpillar development.
Pursuant to these criteria, the following substances were used to control
gypsy moths in 2005: Foray 48 B (22,311 l), Match 050 EC (6,229 l), Karate


2.5 EC (2,525 l), Decis 2.5 EC (884 l) and Dimilin SC 48 (210 l). Based on the
price of the substance, its consumption per unit area (ha) and the aircraft costs,
the control costs per unit area by substance were: 488 HRK/ha (Foray 48 B);
234 HRK/ha (Match 0.5 EC); 242 HRK/ha (Dimilin SC 48); 106 HRK/ha
(Decis 2.5 EC) and 99 HRK/ha (Karate 2.5 EC).
The costs of controlling gypsy moth during 2005 (the total of all treated
areas in the Republic of Croatia) totalled 6,106,190 HRK or an average of


195.06 HRK/ha, regardless of the type of substance used. To determine the
success of the control measures, visual observation and the method of setting
up control plates were used.
Key words: gypsy moth (Lymantria dispar L.), forest ecosystem,
population dynamics, defoliation, insecticides, oak (Quercus robur L.), forest
protection.