Run of the Mass Appearance of the Nun Moth (Lymantria monacha L.) and its Control in Poland in the Years 1978-1985 and the Regeneration of the Assimilation Apparatus in Damaged Stands

1989

41 Abb., 15 Tab., 85 Lit. Ang.

Unselbständiges Werk

4620

200027418

In the years 1978-1985, the nun moth appeared in masses in the forests of north and west parts of Poland. This pest, as typical polyphage, attacked trees of almost all coniferous and deciduous species, in all age classes, and even plants in plantations and nurseries. The abundance of the pest exceeded many times the critical numbers, locally even 100 times. During the flight time, especially in the years 1978-1981, one found the adults in masses not only in the forests, but also in great distances from the forests on lighted buildings of villages and towns. The population of the nun moth was very good health. The activity of predatory and parasitic insects, as well as of microorganisms was almost imperceptible. The nun moth occurred in 208 forest districts, and it was controlled in 208 districts in 12 forest regions. The control was conducted in 1978 on a total area of 20.000 ha, 1979 180.000, 1980 510.000, 1981 1,736.000, 1982 2,303.000, 1983 1,424.000, 1984 139.000 and 1985 1.000. From this area, 87% were pine stands, 10% mixed stands and those with a share of spruce, 3% spruce stands. For the control of the pest, we used first of all insecticides from the group of pyrethroids (Ambush 10EC, Decis 2,5EC, Ripcord 40EC). We also used a stomachic-hormonal (benzyl-urea) product (Dimilin ODC40) and biological products (Dipel, Bactospeine, Thuridan). The concentrates of the insecticides were mixed with diesel oil or water. The expenditure of te suspension amounted to 2-7 1/ha. The threatened stands were sprayed from planes and helicopters equipped with conventional sprayers or atimizers. For complementary spraying, we used terrestrial sprayers L-105, used for the nun moth control in lower parts of crowns. In spruce stands and stand with a share of spruce the treatment were performed twice. Balloons appeared to be very helpful. The were used for showing to the pilot the right direction of incursion and keeping parallel 40-50 m wide distances between individual flights of the plane. The regeneration of the assimilation apparatus depended on the degree of its damage and of tree species. In deciduous trees (oak, beech, birch) and in larch, new leaves appeared in damaged places after 4-6 weeks. Pine stand damaged slightly or to a medium degree regenerated the lost needles, too. Trees in which the resin was tapped regenerated only weekly. Strongly damaged spruce and fir trees died and those damaged to a medium degree tried to regenerate the assimilation apparatus, but after several years they tied, too. In spite of mass, extremely dynamic propagation of the nun moth in the years 1978-1985, we cut only 15.000 ha stands, mainly spruce stands. The scientific supervision of the control action was performed by the Forest Research Institute, the performance of chemical treatments was directed by technical staff of the individual Regional Administrations ...