Adults of Green hawker were collected in light traps in the valley of the river Narewka in Białowieża village, NE Poland (2006-07-22, 1 ♀ at mercurial lamp and 2006-07-23, 3 ♀♀ and 1 ♂ at arclamp). All specimens were caught on ca 2140. The collected individuals were sitting frontally to the lamp so that their body axes were forwardly directed to the source of light. The authors discuss the known cases of light-trapped dragonflies, especially in the zone of temperate climate and in Europe. This phenomenon can be the result of spontaneous activity of dragonflies or their arousal to activity by strong light. Up-to- date observations have shown that there are two possible explanations: in particular cases the first or the second mechanism was involved. For the observations from Białowieża more possible is the second one: Aeshna viridis was multiply found in the valley of the Narewka River, also at the sites where light traps were provided. It seems that many cases of dragonflies attracted to the light source are overlooked for odonatologists do not use the method and other entomologists who set light traps are not interested in dragonflies or underestimate such observations. So for gathering more data on the subject the cooperation of odonatologists and specialists of other insect groups is needed.
On June 15, 2007 in the valley of the Ri- ver Raba near the village Marszowice (sou- thern Poland) Platycnemis pennipes (2 ) and Ischnura elegans (1 ) were caught to a light trap. Both species occurred nume- rously on the river or in an adjacent gravel- pit and they were probably activated by the strong light.
The European corn borer (Ostrinia nubilalis Hbn.) is the most dangerous pest of maize (Zea mays L.) in Poland, requiring intensive control with agrotechnical method for instance by cultivating varieties less damaged by caterpillars, biological measures, and, application of chemical products as last available option. A precise monitoring of the species presence in maize fields is necessary to determine accurately a need and a date for setting out bioformulations containing Trichogramma spp. Currently, nationwide monitoring of O. nubilalis presence is conducted by the Main Inspectorate of Plant Health and Seed Inspection, using mainly pheromone traps characterised by low effectiveness in catching moths (males). On a small scale, regional monitoring is also conducted by the Institute of Plant Protection – National Research Institute, whose decisions about a need and a date for O. nubilalis control are based on simultaneous use of several observation methods. These methods include: observation of moth flights from postharvest maize residues (in entomological chambers), use of light and pheromone traps (of various types and with various pheromones), and observation of egg laying and caterpillar hatching dynamics. By combining several independent observation methods it is possible to precisely determine an optimal time for biological and chemical control of O. nubilalis, thus it is necessary to establish a national network for monitoring that pest with all known methods, covering all Poland.