| Abstrakt: |
Pesticides are products of chemical or biological nature, used to control populations of harmful animal or vegetal organisms. They have been widely used in agriculture, since ancient times. In Romanian forestry, they were promoted especially after the nationalization of the forests, both the foresters and the country's management being concerned with obtaining the highest possible timber production. Insecticides continue to be the most used pesticides. They have been used to control populations of oak-defoliating insects (Lymantria dispar, Tortrix viridana, and geometrid species). Three important periods can be distinguished in the application of insecticides, closely related to the active substance that was the basis of the efficiency and the economy of their use. In the first period (1954-1985), non-selective and persistent organochlorine products, based on DDT and HCH, were used, initially in extremely high doses (30-40 kg/ha), with major adverse effects on the environment, fauna, and human health. It was imposed to carry out some research work leading to the elimination of these shortcomings, succeeding in considerably reducing the consumption norms of these categories of insecticides to only 1 kg/ha. However, the long-term use of organochlorine products has led to the appearance of resistance since the beginning of the 1960s, manifested by a significant number of species. Other non-selective insecticides, such as organophosphorus products and synthetic pyrethroids, were used during 1986-1990. Nor the application of these categories of insecticides was beneficial from an ecological point of view, with most studies indicating high concentrations of these products in the soil and in the food chains of forest ecosystems. A new stage (after 1990), related to the use of insecticides to control forest pests, was the use of selective, chemical, and biological pesticides, applied in extremely low doses and with minimal impact on useful entomofauna, the environment, and human health. We are currently in a transition period, with FSC certification of forests being particularly restrictive in the use of pesticides to control harmful organisms. [ABSTRACT FROM AUTHOR] |
