Determination of the Number of Pine Noctuid (Panolis Flammea Schiff.) in the Crowns of Pine of 2ND and 3RD Age Class Without Felling Trees

1992

4 Lit. Ang.

Unselbständiges Werk

4620

200048872

The substance of the method consists in counting the number of caterpillars fallen of the whole area under one tree or in chosen 1 Quadratmeter of this area after a control spraying of the tree crown with water solution of pyrethroid. On the basis of regression equations, one made tables of the relation between the total number of caterpillars in the crowns and the number of fallen caterpillars. One proved that it was possible to avoid in the practice the felling of trees and to exactly evaluate the number of the pest in crowns by conuting killed caterpillars and reading the result from the table. This method is more effective than traditional one, consisting in counting of living caterpillars in crowns after felling trees on a canvas.