Abstract
Current problems of forest protection concern the declining health of forest stands due to climate change and the resulting extreme weather events such as heat waves, droughts, hurricane winds, heavy rainfalls and floods. Repeated impacts of these factors increase susceptibility of forest stands to pest insects and fungal pathogens. Norway spruce (Picea abies [L.] H. Karst) is sensitive to high air temperatures and water shortage. Long lasting droughts during the last two decades, have been one of the reasons behind Norway spruce dieback due to severe outbreak of European spruce bark beetle Ips typographus (L.) in the mountainous regions of southern Poland. In the Scots pine (Pinus sylvestris L.) stands, water balance disorders have enhanced the colonization of weekend trees by steelblue jewel beetle Phaenops cyanea (F.) and engraver beetle Ips acuminatus (Gyll.), as well as contributed to the spread of fungal diseases caused by Gremmeniella abietina (Lagerb.) Cenangium ferruginosum Fr. and Sphaeropsis sapinea Fr. fungi. Water related stress leads to weakening of oak stands, which are attacked by Agrilus spp. beetles and pathogens from the genus Phytophthora. It is possible that long lasting droughts initiated the spread of infectious ash disease caused by Hymenoscyphus fraxineus (= Chalara fraxinea), which resulted in the epidemic of ash dieback throughout Europe. Until recently, the use of plant protection products was the most common method of forest protection against pest insects and pathogens. Poland’s accession to the European Union has affected the marketing and use of plant protection products in the country. The implementation of the EU legislation (Directive 91/414/EEC, Directive 2009/128/ EC and Regulation No 1107/2009) has resulted in decreased assortment of pesticides registered for the protection of forests. High costs and long registration process considerably limited the interest of producers in placing the plant protection products on the market. Systematic decrease in the number of plant protection products possible to register for use in forestry, as well as the principles of integrated plant protection established in the EU in 2014 call for seeking plant protection methods based on the natural enemies of pests, such as pathogenic microorganisms, parasites and predators. Therefore, contemporary forest protection requires the advancement of integrated methods for pest insect and disease control through developing methods of forecasting forest dangers, the use of natural enemies and agro-technical methods for regulation of pests, as well as the development of decision support systems as a tool facilitating introduction of integrated forest protection principles. Such support systems help to establish optimal terms for the implementation of protection measures, so as to increase their efficiency while limiting the use of chemical pesticides to an absolute minimum.
Effect of neem-derived plant protection products on the isopod species Porcellionides pruinosus (Brandt, 1833)