White grubs - the larvae of Scarabaeidae beetles are soil pests, which can cause damage of turfgrass, pastures and horticultural plants. A two-year field experiment (2012-2013) in grassland near Gotenica was conducted to test different biological control agents; entomopathogenic fungi (Beauveria brongniartii, B. bassiana), entomopathogenic bacteria (Bacillus thuringiensis var. kurstaki, B. thuringiensis var. tenebrionis), and entomopathogenic nematodes (Heterorhabditis bacteriophora) to control white grubs. The application of biological control agents was conducted twice (April and August). Our observations show that several biological control agents are capable of controlling the populations of the first and second instar larvae of different scarab grub species. The efficacy of most biological control agents, however, declines when larvae reach the third instar stage. The most promising combination tested in our study is that of entomopathogenic fungi and H. bacteriophora for controlling the first and second stage instar larvae. In addition, the summer application proved to be more suitable for control of the first stage instar larvae than the spring application.
COBISS.SI-ID: 8042361
The experiment took place in 2013 at six different locations in Kočevje Region (Stari Log, Gotenica, Kačji Potok, Dolnja Briga, Stari Breg, and Novi Lazi). The aim of the experiment was to investigate which soil parameters (presence of grubs, earthworms, pH, content of P2O5, K2O and organic matter in soil) influenced the damage on grasslands caused with wild boar (Sus scrofa [L.]). A significant positive correlation was discovered between the extent of damage due to wild boar rooting in grasslands and the number of grubs (r = 0.73), the weight of grubs (r = 0.69) and the content of P2O5 (r = 0.87) in the soil. The quantity and weight of grubs in soil were significantly influenced by soil pH (r = 0.71/0.72), P2O5 (r = 0.90/0.91), and the content of organic matter (r = 0.74/0.77), while the quantity and weight of earthworms in soil were influenced by the content of K2O (r = 0.81/-0.84). Grubs represent a more important source of protein for wild boars than earthworms; consequently, reducing the quantity of grubs in soil could minimize the extent of damage caused by boars.
COBISS.SI-ID: 8035961
White grubs of different species of scarab beetles (Scarabaeidae) can, when they overmultiply, cause economical damage on grassland. In this paper we present the selected morphological characteristics, which help us in quick distinguishing of white grubs and adults of June beetle (Amphimallon solstitialis), margined vine chafer (Anomala dubia), garden chafer (Phyllopertha horticola), forest cockchafer (Melolontha hippocastani) and common cockchafer (Melolontha melolontha). The special emphasis in the paper is devoted to presentation of life cycles of all 5 scarab beetles recorded in Slovenia.
COBISS.SI-ID: 7691897
In the last years on different regions in Slovenia we often established the damage on grasslands and fields that was caused by larvae of the common cockchafer (Melolontha melolontha L.). The farmers in the statistical region of Savinjska and Koroška are warning about the demage connected with activity of grubs on grasslands. The damage on overhead plant parts in the grass were noted in the end of April or in the begining of May. The damage of grass root system were in the years 2011 and 2012 noted in the end of August to the end of October. The beetle Galeruca tanaceti (L.) from the family Chrysomelidae and garden chafer (Phyllopertha horticola [L.]) from the family Scarabaeidae which are more and more important pests on grassland on the statistical region of Savinjska and Koroška are presented in the present article. The results of our observations on the field and identification results of the larvas from some locations are also presented in the paper.
COBISS.SI-ID: 7691385
Since 2001 several outbreaks of common cockchafer (Melolontha melolontha L.) have been detected and caused damages on Slovenian grassland. The control of common cockchafer grubs is even more difficult because no insecticides are registered in Slovenia for this purpose. In order to monitor pest population dynamics and to find out cost-effective control methods of adult cockchafers, two different light traps and nine alcohol - pheromone traps were tested in our field trail. We compared white and green light traps and it was noticed that a larger number of adults were trapped on the white one. In alcohol - pheromone traps the most attractive to adult cockchafers was the trap filled with the mixture of 1,4 benzoquinone + toluquinone + cis-3-hexen-1-ol, followed by the traps filled with cis-3-hexen-1-ol and toloquinone individually. Besides, also trap filled with 3-ethyl acetate was successful. In the coming season, we intend to upgrade the testing methods in order to verify their suitability for the control of common cockchafer in practice.