Original scientific paper
Intensity of Infection with Yellow Mistletoe and White-berried Mistletoe on the Area of the Forest Administrations Vinkovci and Nova Gradiška
Marilena Idžojtić
; Šumarski fakultet Sveučilišta u Zagrebu
Milan Glavaš
; Šumarski fakultet Sveučilišta u Zagrebu
Marko Zebec
; Šumarski fakultet Sveučilišta u Zagrebu
Renata Pernar
; Šumarski fakultet Sveučilišta u Zagrebu
Perica Beuk
; Hrvatske šume UŠP Vinkovci
Ivan Prgić
; Hrvatske šume UŠP Nova Gradiška
Abstract
The intensity of infection of different hosts with yellow mistletoe (Loranthus europaeus Jacq.) and white-berried mistletoe (Viscum album L. ssp. album) in the area of 12 forest offices of the Forest Administration Vinkovci and 9 forest offices of the Forest Administration Nova Gradiška was investigated. The investigated hosts were: sessile oak (Quercus petraea /Matt./ Liebl.), pedunculate oak (Q. robur L.), narrow-leaved ash (Fraxinus angustifolia Vahl), black walnut (Juglans nigra L.), small-leaved lime (Tilia cordata Mill.), common maple (Acer campestre L.), common hornbeam (Carpinus betulus L.), wild pear (Pyrus pyraster Burgsd.), common locust (Robinia pseudoacacia L.) and Canadian poplar (Populus ×canadensis Moench). The intensity of infection was very different in the individual compartments, management units and forest offices.
In the area of the Forest Administration Vinkovci from the total number of examined pedunculate oak trees 7.6 % were infected with yellow mistletoe. On the average on each of the infected trees there were 2.5 mistletoe plants, and the largest number on one tree was 17. The largest infection was noted in the Management Unit Vrapčana, of the Forest Office Vinkovci (20.1 %). In the area of the Forest Administration Nova Gradiška 10.5 % of the examined pedunculate oak trees were infected with yellow mistletoe. On the infected trees there were 2 mistletoe plants on the average, and the largest number of plants on one tree was 9. In the Management Unit Glovac-Renovica, of the Forest Office Trnjani, there was considerably more infestation than in other management units (35.5 %). For the Forest Administration Vinkovci the spacial distribution of mistletoe infestation intensity of the pedunculate oak in six most infested management units was presented. Compared with previous research, the intensity of mistletoe infestation of the pedunculate oak is greater in the area of the Forest Administration Vinkovci and Nova Gradiška than in the Forest Administration Bjelovar, and smaller than in the Forest Administration Požega.
On the sessile oak yellow mistletoe was investigated in the area of the Forest Administration Nova Gradiška, where mistletoe was observed on 4.6 % of the examined trees. On the infected trees there were 2 mistletoe plants on the average, and the highest number of plants on one tree was 5. The largest infestation was found in the Management Unit Južni Dilj, of the Forest Office Slavonski Brod, where 9.3 % of the examined trees were infected. Previous researches show that the intensity of mistletoe infestation of the sessile oak in the area of the Forest Administration Nova Gradiška is greater than in the Forest Administration Bjelovar, and smaller than in the Forest Administration Požega.
Out of the total number of examined narrow–leaved ash trees in the area of Forest Administration Vinkovci, 2.7 %, were infected with white-berried mistletoe, with an average of 2 mistletoe plants per infected tree; the largest number of plants per tree was 5. In the area of the Forest Administration Nova Gradiška 7.3 % of the examined narrow-leaved ash trees was infected with mistletoe, with an average of 4 mistletoe plants per tree; the largest number of mistletoe plants on one tree was 60.
Mistletoes are a constituent part of forest eco-systems and they do not represent a special threat to their hosts, if the infection intensity is not high. Although the percentage of infested trees varied in individual compartments, i.e. management units, the important fact was that the number of yellow mistletoe plants on infested sessile and pedunculate oak trees was not high (averaging 2 mistletoe plants per tree). The state of infection of the narrow-leaved ash was partly different in individual management units in the Forest Administration Nova Gradiška, where on the average a higher number of white-berried mistletoe plants on the infested trees was observed, and a relatively large number of plants on some trees.
Keywords
Hrčak ID:
31261
URI
Publication date:
31.10.2006.
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