| Abstract: | Modification in discase-sensibility of forest plants by herbicide treatment. I. Field trials with Lophodermium pinastri. The effect of two herbicides TOP-KH (salt of 2,4,5-T) and Casoron G (Dichlobenil) on incidence of Lophodermium pinastri on Scots pine (Pinus sylvestrií L.) was investigated in field trials with potted plants. Treatment with TOP-KH led to increase in infection with higher herbicide concentrations and to higher numbers of severely infected plants in comparison with controls. Differences were greatest in spring. With Casoron G, however, smaller numbers of sevcrely infected plants were seen in spring and at the end of the growing season the damage was not much greater than in the controls. Possible reasons for changes in degree of infection are discussed as well as effects that could be expected on the epidemiology of pine needle cast. |
