In 2012, we conducted a 5-block field experiment in Gotenica (Slovenia), in which we tested different control methods of white grubs on grassland. In an experiment we studied the insecticidal activity of different products which active ingredients are biological agents Beauveria brongniartii, B. bassiana, Bacillus thuringiensis var. kurstaki, B. thuringiensis var. tenebrionis and Heterorhabditis bacteriophora. During the time period we applied biological agents twice, namely on 17th April and 31st August. Entomopathogenic nematodes (H. bacteriophora) were applied two weeks after the application of other biological control agents. With a standard detection methods of soil pests - soil excavation - on 16th April, 24th May, 20th June, 10th July, 9th August, 10th September, 22nd October, and 20th November we monitored the population dynamics of white grubs in the soil. The morphological analysis of white grubs showed the major presence of June beetle (Amphimallon solstitiale), margined vine chafer (Anomala dubia), garden chafer (Phyllopertha horticola) and in smaller extent also of common cockchafer (Melolontha melolontha) and forest cockchafer (Melolontha hippocastani). Results showed that the average number of white grubs (L1 and L2) after the application of biological agents into the soil, decreased under the economical threshold of noxiousness (from 30 to 40 white grubs L1/m2, from 20 to 30 white grubs L2/m2, respectively), meanwhile the reduction of developmental stage L3 of white grubs only was attained when products with active ingredients of entomopathogenic fungus in a combination with entomopathogenic nematodes were used.
COBISS.SI-ID: 7690105
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