ENTOMOPATHOGENIC FUNGUS ENTOMOPHAGA MAIMAIGA AND INTEGRATED PEST MANAGEMENT IN SERBIA.

During the latest outbreak of the gypsy moth in Serbia (2009-2014), some areas of Central Serbia were particularly endangered, and one of them was Krusevac region, where the forests give way to orchards in the pattern resembling the tiger's skin. Since the number of the laid egg masses in the autumn 2013 guaranteed the defoliation of both forest tree species and agricultural crops, and the presence of E. maimaigo, in Central Serbia had already been determined, at 30 selected plots the assisted spread of it was performed, through the introduction of the infectious inoculum in the beech and oak forests which border the orchards. Since there was dealt with the living organism--fungus, which is particularly susceptible to the weather conditions (temperature and air humidity, as well as the precipitation), and under the conditions of the global warming and great drought, the special recipe for the preparation of inoculum was made. In the following year the mass epizootic of the gypsy moth caterpillars, of the younger instars (L2 and L3), occurred, which implies that E. maimaiga caused the crash of the outbreak of this most harmful species of the defoliating insects of the forests and orchards.

Exploring continental-scale stand health - N : P ratio relationships for European forests.

Understanding the relationship between nitrogen (N) availability and stand health in forest ecosystems is crucial, because a large proportion of European forests is subjected to N-deposition levels beyond their retention capacity. We used data from a long-term forest monitoring programme (ICP Forests) to test the relationship between an index of N availability, foliar nitrogen : phosphorus (N : P) ratios, tree defoliation and discoloration. We hypothesized a segmented response of stand health to N : P ratios and an improved model-fit after correcting for climatic covariates. In accordance with the hypothesis, we found a segmented response with a breakpoint for conifer defoliation at N : P ratios as low as 7.3. Inclusion of climatic variables improved the fit of the models, but there was significant collinearity with N : P. Increases in N availability appear, at least for conifers, to have a negative effect on tree health even under N-limiting conditions. Regulation of N-deposition levels is consequently as timely as ever. We propose that increases in tree defoliation, other than resulting in serious plant fitness issues, may represent early diagnostic symptoms of N-addition related imbalances.