Forster, B.; Knizek, M.; Grodzki, W. (eds.) 1999: Methodology afForest Insect and Disease Survey in Central Europe.
Proceedings ofthe Second Workshop ofthe IUFRO WP 7.03 .10, Apri120-23, 1999, Sion-Chii.teauneuf, Switzerland.
Binnensdorf, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL) 124-128.
Introduction
Conditions of lps typographus population in the Carpathians in 1998
Yaroslav SLOBODYAN Ukrainian Mountain Forestry
Research Institute Hrushewsky, 3I UA-284000, Ivano-Frankivsk
Ukraine
Norway spruse (Picea abies L. ) forests occupy more than 500,000 ha, which is approximately 500/o of forest covered area in mountain zone of Ukrainian Carpathians.
Therefore bark beetles problem is very much actual in this region. Among the bark beetles, Ips typographus L. is the most important pest on spruse. Now its population grows intensively due to repeated windthrowns and considerable area of root rot infestations (caused by Heterobasidion annosum Fr. Bref and Armillarieiia mellea Fr. ex. Vahl Karst).
One of the causes of bark beetles development in Carpathians is the balance disturbance of spruce stands spatial and age structure. Since middle age, the monocultures as a rule are characterized by decreased resistance to harmful abiotic and biotic agents. In some forest enterprises up to 60-800/o of spruce monocultures are the foci of drying.
The program included
the selection of stands in the two monitoring points for pheromone traps installation,
Ips typographus population counts in pheromone traps, bark beetles analysis of felled trap trees.
Objects and methods
Ips typographus population was investigated in the 2 monitoring points. The Object I is located in the Mokhnatske forestry, Borinskij State Forest Enterprise (breeding specialization), Lviv region ( Northmegaslope). The Object 2 is located in the Sinevir-Polyanske forestry, National Nature Park "Sinevir " , Zacarpathians region (Southmegaslope ). The both objects are located in the spruse stands and each of it occupies more that 50 ha.
Traps of "Taison" (Germany) and lures "Pheroprax" (Poland) were used.
Pheromone traps were installed on the 4th of June I998, at I 0 traps per object (at 2 lures per I trap). Distance between traps was equal to IS m, distance from traps to forest wall was equal to 20 m
Bark beetles counts in traps were carried out every 10 days, the last count was finished on the 22 nd of August 1998 on the Object 1 and on the 12th of August 1998 on the Object 2.
Besides that, on the 4th of June 1998, 5 trap trees (mainly weakened ones of the 2nd Kraft class) were felled in the each of Objects to study bark beetles population density. Trees were analyzed on the 31st of July in 4 half-meter sections: 1- basal (0 .5-1. 0 m above the ground level ), 2- middle (between tree base and crown base ), 3 -at the crown base and 4 - in the middle of the crown.
The number of mother galleries, mating chambers, young beetles were estimated in the sections, which allow to evaluate old and young bark beetle generation density.
The old generation density (infestation) of Ips typographys was evaluated as a sum of mother galleries and mating chambers per 1 dm 2 of stem surface.
The young generation density (production) was evaluated as a number of young beetles per 1 dm2 of stem surface.
Forest pathological stands characteristics
The forest in the area under investigation consists of pure spruse (with admixture of fir and beech) 45-150- aged stands, which are mainly plantations and partially of natural origin. The stands of 55-80 years old with density equal to 0.5-0.7 predominate.
The main spruse covered area is located on 950-1200 m above sea level. The slopes are 15-35
°
of southern exposition.Phytosanitary state of the main part of stands is not satisfactory because of root rots, windthrowns, storms and stem Analysis of sanitary felling for 1988-1998 shows the considerable damage of spruce stands in 1990 connected with mass windthrowns in Carpathians. Windthrowns of 1990 have disturbed the stable development · of forest ecosystems and were the cause of mass bark beetles propagation, especially Ips typographus, which culminated in 1995-1996.
Table 1- Spruce desiccation dynamics for 10 years after sanitary felling data for National Nature Park "Sinevir" (Sinevil;-Polyanske forestry). Ukraine,1998 Year Total sanitary felling, Selective felling, Total,
thous. m3 thous. m3 thous. m3
1 2 3 4
1988
-
5814 58141989 10724 6125 16849
1990 180953 1506 182459
1991 56305 4721 61026
1992 20287 5032 25319
1993 19926 12239 32165
1994 13184 18072 31256
1995 7631 5798 13429
1996 4302 4455 8757
1997 6407 9032 15439
1998 11522 722 12244
Bark Beetles analysis in the trap trees
The trap trees were selected on 04.06.98, they looked weakened and belonged to the 2nd Kraft class. Seven from ten felled trees were damaged by root rot. In 4 weeks after felling, the numder of mother galleries of Ips typographus was equal to 1. 7 per 1 dm2 . The number of larvae on the separate sections amounted to 55 per 1 dm2. The bark beetles were the most numerous in the middle part of stem. At the same time, expansion was not equal in the different parts of sections. The beginning of galleries forming was observed on the lower and lateral surfase of felled tree, while they were 18-20 days old on the upper part of section.
At the first turn, the bark beetles populated the weakened by root rot trees and almost never they were found in the healthy spruces. The young beetles of Ips typographus were observed during their additive feeding in the 2 trap trees of Object 1.
Trap trees analysis after 8 weeks after felling showed considerable quantity of Ips typographus almost in all sections (Table 2).
Section area did not differ significantly in the two Objects ( p > 0.001 ). On the whole, during observation period Ips typographus L. and Pityogenes chalcographus L.
predominated on the populated trap trees, Ips amitinus Eichn. was observed in insignificant quantity. Ips duplicatus was not found in trap trees.
Table 2- Indices of Ips typographus population in the trap trees (Section: 1-basal 0.5-1 m above the ground level, 2-middle between tree base and crown base, 3- at the crown base, 4-in the middle of the crown). Ukraine, 1998.
Objekt Tree, N Section Section Number per 1 dm2
area, dm2 mating mother infestation young chambers galleries density beetles
(product.)
1 2 3 4 5 6 7 8
1 1 1 39.2 0.15 0.43 0.58 0.61
1 1 2 30.8 0.77 1.69 2.46 2.88
1 1 3 28.6 0.31 0.68 0.99 0.90
1 1 4 20.4 0.14 0.44 0.58 0.44
1 2 1 40.6 0.19 0.49 0.68 0.61
1 2 2 32.6 0.49 11.34 1.83 3.19
1 2 3 29.9 0.26 0.80 1.06 0.93
1 2 4 23.5 0.25 0.51 0.76 0.51
1 3 1 26.7 0.29 0.75 1.04 0.97
1 3 2 21.0 0.76 1.76 2.52 3.23
1 3 3 16.8 0.59 1.60 2.19 1.90
1 3 4 8.9 0.56 1.23 1.79 1.46
1 4 1 42.8 0.21 0.57 0.74 0.70
1 4 2 33.7 0.74 1.75 2.49 2.52
1 4 3 28.6 0.24 0.66 0.90 0.80
1 4 4 22.5 0.17 0.26 0.43 0.31
1 2 3 4 5 6 7 8
1 5 1 40.1 0.00 0.00 0.00 0.00
1 5 2 31.6 0.1 0.22 0.32 0.25
1 5 3 28.9 0.07 0.17 0.24 0.17
1 5 4 21.3 0.00 0.00 0.00 0.00
2 1 1 34.7 0.11 0.3I 0.42 0.37
2 1 2 24.3 0.64 1.56 2.20 3.95
2 I 3 I7.4 0.35 0.77 1.12 0.86
2 1 4 13.6 0.18 0.48 0.66 0.44
2 2 1 41.9 0.07 0.14 0.2I 0.19
2 2 2 29.4 0.13 0.37 0.50 1.36
2 2 3 26.5 0.09 0.22 0.3I 0.26
2 2 4 I7.1 0.11 0.23 0.34 0.23
2 3 1 31.5 0.12 0.33 0.45 0.38
2 3 2 24.9. 0.72 1.72 2.44 4.05
2 3 3 20.1 0.34 0.89 1.23 0.79
2 3 4 13.5 0.22 0.5I 0.73 0.59
2 4 1 34.6 0.00 0.00 0.00 0.00
2 4 2 28.5 0.14 0.35 0.49 0.94
2 4 3 23.6. 0.08 0.25 0.33 0.46
2 4 4 I8.3 0.00 0.00 0.00 0.00
2 5 1 27.2 0.00 0.00 0.00 0.00
2 5 2 22.4 0.13 0.3I 0.44 0.31
2 5 3 I7.6 0.06 0.17 0.23 0.11
2 5 4 9.8 0.00 0.00 0.00 0.00
Results of Ips typographus assessment in pheromone traps
Ips typographus population in 1998 had a large density (Fig.1 -Bark beetles counts in the pheromone traps (Carpathians, Ukraine, 1998 ), it s number was higher in the Object 1 in each date of assessment. The spring flight of beetles was prolonged with maximum on the 1st decade of June. Decrease of trapped beetles amount in the 2nd half of June was connected in considerable degree with rainy weather. Beetles population increased at the end of June at the expense of mass flight of females which laid the eggs of sister generation. After pheromone traps the main activity of Ips typographus was observed in July, which was in I998 favorable for bark beetles development.
In total, during June-August 1998, 99828 and 64223 beetles of Ips typographus was trapped in Object 1 and Object 2 respectively. Such large amount of the pest in the traps shows the extremely high susceptibility of spruce stands ecosystems in Ukrainian Carpathians for Ips typographus propagation.
Engraver beetle Pityogenes chalcographus was entrapped by used pheromone traps too, the maximal number (98 beetles per I trap) was counted on the 23rd of June 1998.
2500
2000
1500
1000
. 500
0
Ul6·
13.06
14.00- 23.06
24.06- 3.07
4.07- 13.07
14.07- 23.07 Period oflnlppiaa
' 24.07- 2.08
1---
3.011- 12.08
13.08- 22.08
Fig .I -Bark beetles cowtts in the pheromone traps (Cmpathians, Ukraine, 1998)
Sometimes beetles of Ips duplicatus were found in Pheroprax traps in insignificant quantity. The question of this pheromone attractivity for given beetle requires the further investigations.
We have found some entomophages of stem pests in pheromone traps, namely Tranasimus formicarius L., Rhizophagus dispar Payk., but their number was not more than 3-5 specimen per trap for 1 decade of trapping.
Conclusions
Ips typographus population in Ukrainian Carpathians is characterized by considerable quantity and fluctuations which is caused by extreme susceptibility of spruce stands to mass pest propagation.
One of the main causes of mass bark beetles propagation are windthrowns and root rots, which considerably disturb the sustain development of spruce ecosystems.
Ips typographus population density in the felled trap trees of Object 1 was higher, than in the trees of Object 2. The highest population density was observed in the section 2 of each tree.
The more number of Ips typographus beetles was entrapped by Pheroprax traps on the Object 1 comparing to Object 2.
Pityogenes chalcographus, Ips duplicatus and sometimes entomophages of stem pests were found in Pheroprax traps.
Solving of Ips typographus problem requires the complex approach with participation of different interested European countries and pennanent monitoring.
