EFFECTIVE PROTECTION AGAINST PINE WEEVIL (HYLOBIUS ABIETIS) DAMAGES IN CONIFEROUS PLANTATIONS

Climate change manifest itself as increased natural disturbances. These effects can be reduced by planting adapted forest reproductive material. Such plantation ensure the source of raw material for bioeconomy, but are affected by dendrophagous insects, including pine weevil (Hylobius abietis). This species is estimated to cause 120 million EUR financial losses annually. Untreated coniferous seedlings have very high mortality, therefore pesticides are applied in nurseries, before delivering the plants to forest. Use of pesticides is have a negative impact on the environment. Therefore several European countries are working on the development of protective agents based on biological components. The purpose of this study is to assess the performance of a new plant oil-based protective agent, developed in Latvia. Study is based on six experimental sites � fresh clearcuts, where soil was prepared in furrows and coniferous seedling planted at spring. One of the sites was regenerated by pine and five by spruce. Three types of treatments were ensured: by protection agent (woodcoat), repellent, produced in Latvia � Jifte (weak concentration, standard concentration and strong concentration) and control (untreated trees). Inventory was performed by visually assessing the trunk of young trees after the vegetation period and reporting the level of damages. The repellent Jifte ensured satisfactory level of protection � in all of the assessed sites the proportion of damaged seedling was below 20%: it ranged from 5% to 11%. The developed new repellent in low and standard concentrations endured the level of protection comparable to that of the established (commercially available) alternative, in high concentration � even better protection. Thus, further analysis and development work should focus on economic feasibility of the new solution, to ensure, that it can be taken up and used at a large scale in potential areas of need � northern Europe and northern America.