DIGITALNA ARHIVA ŠUMARSKOG LISTA
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|ŠUMARSKI LIST 7-8/2013 str. 38 <-- 38 --> PDF|
and secure an area for mating and oviposition. This area consists of a hole and a chamber beneath the bark known as a "nuptial chamber". The females construct a tunnel ("maternal gallery") beneath the nuptial chamber in which to lay eggs. In all species of the Ips genus, several females (usually two or three) join each male in his nuptial chamber (Wermelinger, 2004). At lower elevations, overwintering I. typographus beetles emerge in April/May and produce one or two generations of offspring per year with the main peaks of bark beetle emergence in July and August/September. At elevations above 1,000 m a.s.l., this species produces only one generation of offspring per year (Wermelinger, 2004). Trap trees using and removing of infested logs from the forests are basic tools of the forest protection against Ips typhraphus during these days. Also pheromone traps are massively used for these purposes in spite of their still discussed efficiency by many authors (e.g Dimitri et al., 1992; Lobinger and Skatulla, 1996; Wichmann and Ravn, 2001). Some authors show that only 3–10 % of bark-beetle population may be trapped by using of high density of the pheromone traps (Weslien and Lindelöw, 1990; Lobinger and Skatulla, 1996). Their potential efficiency can be furthermore decrease by capturing of predators of the beetles. Some special construction of pheromone traps was suggested for reducing of this negative effect (Martin et al., 2013) for related species of I. sexdentatus (Börner, 1776). Also type of wrapper play very significant role in number of trapped beetle (Nakládal and Sova, 2010). Bakke et al. (1989) discovered that pheromone dispensers containing methylbutenol, (–)cis-verbenol and ipsdienol, which are the three components of the Ips typographus pheromone, retained their effectiveness for 8 years when they are stored in sealed aluminium bags in an unheated room in the cellar of a storehouse.
A key component of the lures for pheromone traps is cis-verbenol (e.g. Jakuš and Blaženec, 2002). Many types of pheromone dispensers (based on this component) with different efficiency are in the market during these days. E.g., Zahradník et al. (1990) compared efficiency of PHEROPRAX and IT ETOKAP. Holuša et al. (2010) compared efficiency of ID Ecolure, Pheagr IDU and Duplodor for the double spined bark beetle (Ips duplicatus /C.R. Sahlberg, 1836/). Jakuš and Šimko (2000) compared IT ECOLURE (with 6 different levels of release rates) and PHEROPRAX at pheromone trap barriers.
In last time, the all season pheromone dispensers begin offered in the market. Eg., guaranteed efficiency of 18–20 weeks is declared for both ECOLURE TUBUS and ECOLURE MEGA. These dispensers do not require additional opening dispenser bag and also their replacement. This strong advantage may be counterbalanced by their obvious low efficiency (Nakládal and Sova, 2010). Basic difference between classic ECOLURE CLASSIC and all season ECOLURE TUBUS dispenser is only in type of releasing wrapper. Effective compounds are packed in classic clipping bag in case of ECOLURE CLASSIC, and in special gauzy plastic tube with free filling in case of ECOLURE TUBUS. ECOLURE MEGA tested in this experiment has similar construction like ECOLURE CLASSIC.
The aim of this study is to compare the efficiency of ECOLURE MEGA (all season dispenser) and efficiency of ECOLURE CLASSIC (standard dispenser).
Material and methods
Materijali i metode
The efficiency of the standard (ECOLURE CLASSIC) and all season (ECOLURE MEGA) pheromone dispensers was evaluated in this experiment in 2010. ECOLURE MEGA has guaranteed efficiency of 18–20 weeks. This time was taken like comparing of efficiency of the ECLURE CLASSIC (with efficiency of 5 weeks after first clip of wrapping bag, second clip prolong efficiency by next 7–10 days). IT ECOLURE CLASSIC (rank 080411) and IT ECOLURE MEGA (rank 080411) were used for the test. Both are pheromone dispensers on Ips typographus compounding from (S)-cis-verbenol (3 %), alcohols and solvents (85.2 %) and synergic components (11.8 %). ECOLURE CLASSIC has 2.5 g of effective compounds and ECOLURE TUBUS has 3 g in comparison.
The study was made in commercial forests near the Písek city (south Bohemia – Czech Republic) in Záhoří management-plan area sited near the Záhoří village (Loc: 49°21’1"N, 14°12’1"E). Twenty pairs of Theysohn type of pheromone traps (one trap in pair with ECOLURE MEGA and one with ECOLURE CLASSIC dispenser) were installed to the forest complex with average age of 90 year and 70 % of spruce portion of surrounding forests. Exact data and position of all pairs of traps are mentioned in table 1.
Pheromone traps were positioned on clear-cuts in 15 m distances from the forest edge (in according with commending of pheromone dispenser producer). Distance of traps in pair was 70 m by following way that both were placed on stand wall oriented on the same cardinal point. Strongly weedy places were measured by herbicides 1.5 m around the trap.
The comparing duration of experiment was 133 days in 2010. The experiment was finish in guaranteed efficiency term of ECOLURE MEGA (18–20 weeks = 126–140 days). Pheromone traps were lured at 1st May by pheromone dispensers. Traps were checked every 10 days approximately to the 10th September (exact date of sampling: 10th May, 20th May, 30th May, 12th June, 22nd June, 2nd July, 12th July, 22nd July, 1st August, 11th August, 21st August, 31st August, 10th September).
The first bag with efficiency substance of ECOLURE CLASSIC was more opened by scissors in 5th June and replaced by second one in 12th July. The second was more opened 17th June and replaced by third one in 22nd July. The third