Charakterystyka wytępowania motyli i poczwarek strzygom choinówki (Panolis flammea Schiff.) w okresie międzygradacyjnym w drzewostanach sosnowych w Nadl. Potrzebowice i Tuczno

摘要

Strzygonia choinówka to jeden z gatunków, który z uwagi na tendencje do masowych pojawów (gradacji), jest stałym obiektem zainteresowań ochrony lasu w krajach europejskich (1,5,7, 8,11,12). W Polsce strzygonia podlega kontroli w stadium poczwarki i motyla. Oceny stanu występowania poczwarek dokonuje się podczas jesiennej kontroli występowania pierwotnych szkodników sosny, przeszukując ściółkę na powierzchniach podokapowych, których obszar określa rzut korony drzewa. Rozeznania pod względem występowania motyli dokonuje się za pomocą pułapek feromonowych w okresie rójki, tj. od wczesnej wiosny do maja. Mimo stałej kontroli w drzewostanach sosnowych bardzo często masowe pojawy są zaskoczeniem dla służb leśnych i do stosowania zabiegów ratujących drzewostany przystępuje się wtedy, gdy straty w aparacie asymilacyjnym są już znaczne. Może to świadczyć o niedoskonałości metod prognostycznych.%In two forest objects, covering each several hundred hectares of pine stands on coniferous forest sites differing in age, stand density and stand quality, there were observations carried out during several years in the inter-gradation period, with capturing butterflies and pupae of pine beauty. In each of stands there were trees selected for studies, on which in spring there was a catching of butterflies carried out, using pheromone traps containing the Pandor preparation, hung at the height of 2 m above the ground. Under the same trees there were estimations made on the pupae density in autumn. No relationships were found between the number of butterflies caught and the pupae density found, and stand characteristics studied — such as sites, stand density, and stand quality class. No relationships were also shown between quantitative occurrence of pine beauty and characteristics of individual trees, such as age, dbh, height, crown length, crown compactness, and bole branching. There were however areas of stands shown in both study objects, where butterflies numbers and pupae numbers increased, but the regions of those numbers did not cover each other. That situation was treated as a picture of asynchronic model of population numbers dynamics withhin the space, pointing out to a little likelihood that the species would occur in mass quantities. The fact that regions of increased occurrence of butterflies caught in pheromone traps and the increased density of pupae found under crowns did not cover each other, was the cause of the lack of relationships between those features in individual years of observations. Such a relationship was however shown for individual trees, as related to the average density of pupae during the whole observation period, and the numbers of butterflies caught in traps at that time.