Сузбијанје велике тополине буба листаре Melasoma populi L . (Coleoptera, Chrysomelidae) препаратом Novodor / Controling the red poplar leaf beetle Melasoma populi L. (Coleoptera, Chrysomelidae) with Novodor treatment

Novodor is a microbiological insecticide based on δ endotoxin from Bacillus thuringiensis spores. It was originally made for the purpose of controlling Colorado potato beetle (Leptinotarsa decemlineata). The aim of this study was to test the possibility of controlling red poplar leaf beetle (Melasoma populi) with this insecticide. Four experiments were set up with the aim of determining the possibility of controlling this leaf beetle. The experiments proved that the larvae of the first and the older larval stages can be succesfully controlled in both laboratory and field conditions. The first experiment was conducted in laboratory conditions. The mortality of the first instar larvae was 100%, only one day aſter spraying the leaves with Novodor. Mortality of the older larvae was 89% five days aſter the treatment. Although a few of the larvae survived, they stopped eating, which proves the effect of the used insecticide. The second experiment was conducted in field con- ditions, on three groups of willows planted in plastic buckets. The willows were collected from the Lugomir river banks. They were transplanted and protected with a marquisette cloth. The introduced insects mated and subsequently laid eggs. A few days aſter the eggs were hatched the experimental group of willows was sprayed with Novodor. Some of the larvae ceased eating aſter an hour, while the rest of them stopped eating by the end of the day. They were all dead by the next day, while the larvae in the control group continued eating the young leaves. Aſter around three weeks, most of the leaves in the control group were damaged and there were 28 old larvae and three pupae. On the other hand, the willows in the experimental group were untouched, and there were only collonies of dead young larvae. The third experiment was set up on two willow branches which were protected with a marquisette cloth. The experiment was terminated because it could not have been conducted the way it had been planned due to bad weather. The fourth experiment was, like experiment 2, conducted in plastic buckets, but instead of willows, this time young poplars from Resava river banks were used and instead of larvae, the experiment was conducted on adult beetles. This experiment proved that Novodor doesn’t affect the adult Melasoma populi beetles at all. The insects in the group that was sprayed kept mating even on the protective cloth. All in all, these experiments prove that Novodor can be succesfully used for the supression of Melasoma populi larvae, but the adult beetles are not susceptible to it. Based on the result of this study and the results of the studies conducted on other Chrysomelidae species in forestry and agriculture, this insecticide can be used with great success. Therefore, it should be introduced into forestry practice as soon as possible. 108