SummaryFour entomopathogenic nematode species (Steinernema feltiae, S. carpocapsae, Heterorhabditis bacteriophora, and H. megidis) were tested in a laboratory bioassay for the efficacy of these pathogens in controlling the larvae and adults of the Colorado potato beetle, Leptinotarsa decemlineata. The main aim of the study was to develop an efficient sustainable control method against the pest. With this we could develop a strategy of potato production with the intention of diminishing or even preventing the appearance of pest resistance to insecticides. The activity of these biological agents was assessed at three different temperatures (15, 20, and 25 °C) and three concentrations (200, 1000, and 2000 infective juveniles per individual). Mortality of three stages (young and old larvae and adults) was determined 2, 4, and 7 days after treatment. At 15 °C entomopathogenic nematodes showed the lowest efficacy against all insect stages. No significant differences in efficacy was determined at 20 and 25 °C as all nematodes caused prompt death of all stages. At all temperatures young larvae were most susceptible. However, when controlling overwintered adults for the purpose of preventing the mass appearance of Colorado potato beetle, we recommend an application of higher concentrations of S. feltiae suspension.

The results of the monitoring of Thysanoptera species on cultivated plants in are presented in this study. The aim of the investigation was to study the host plant distribution of the predator Aeolothrips intermedius Bagnall and its potential prey. Banded thrips were found on 30 different host plant species belonging to 16 botanical families, always in mixed populations with phytophagous or facultative phytophagous insects (including 18 Thysanoptera species). On the vegetative parts of the cultivated plants, banded thrips were found less numerous in spite of the massive population of some harmful thrips species. This indicates highly important role of pollen as alternative food for Aeolothrips intermedius.

Azadirachtin, refined rape oil and slaked lime Á three natural substances with insecticidal potential Á were tested under laboratory conditions for their efficacy against larvae and adults of Colorado potato beetle, Leptinotarsa decemlineata, at 158C, 208C, and 258C. General statistical analysis (all developmental stages and all insecticidal substances taken into account) was performed on the results of the mortality rates of the individuals and no statistically significant differences between the temperatures were observed on the fifth day after application. At all temperatures, the influence of insecticidal substances in question as well as the interaction between the insecticidal substance and the developmental stage of the pest on mortality rates were significant. The individual statistical analysis (a specified developmental stage of the pest at a specified temperature) revealed the maximum efficacy of the refined rape oil at 158C and 208C, the adults being the most sensitive developmental stage (mortality rate about 90%). Other substances tested were less effective, and in general the mortality rate of either larvae or adults did not exceed 50%. In the case that the efficacy of the refined rape oil in controlling the population of the adults of the Colorado potato beetle is confirmed also in field trials, this could be the basis for a better strategy in controlling the overwintered Colorado potato beetles on potato.

The Hungarian investigator Janos Frivaldszky published results of faunal studies on territories that included some parts of the present Republic of Serbia (Frivaldszky, 1877). This paper reported, among others things, the finding of the species Sympetrum depressiusculum (S?lys, 1841) at the Uljma local?ity in South Banat. It represents the first data indicating the presence of this species in Serbia. For unknown reasons, this paper was not cited by the majority of workers that performed odonatological investigations in this region. Until the present time, there were no confirmations of the presence of this species either in Banat or in Serbia. The risk of oblivion of the finding published by Frivaldszky was suspended by recent findings of this species.