INVESTIGATIONS REGARDING THE COLORADO POTATO BEETLE (LEPTINOTARSA DECEMLINEATA) ON SOME SPECIES OF POTATO TO DIDACTICAL BASE OF TIMISOARA USAB AND HATEG LOCALITY, HUNEDOARA DISTRICT

Among the years 1923-1925 at the laboratories of biological investigations, of Harvard University it were took place experiments that followed to a publication of a report concerning the selection capacity of the nutrition by the Colorado beetle. Recently, it was published one or two additional works referring to choose as testifier plant of the potato by the Colorado beetle and thus that problem appeared good for investigation. Besides its importance as pest of the potato cultures the Colorado beetle was of special interest by the cause of obviously change of its type of nutrition with leaves of domestic potato (Solanum tuberosum) that took place with more than a century ago, when it was firstly remarked that it feed with the leaves of wild potato (Solanum rostratum). However, the preferences of that pest face to the testifier weren't so clear and that meant it were realized some studies by more entomologist from abroad, while in our country the investigations in that domain were poor and in consequences it might be completed and further improved. After the bibliographic study made, the main purpose of the investigations was to identify some Romanian and abroad species of Solanum tuberosum preferred as testifier plant the Colorado beetle and with a great sensibility to its attack, in regions (heal and plain) to the weather conditions. For realizing some investigations during the years 2012, the experimental field was placed to Didactical Base of Timisoara USAB, Timis district and to familiar farm from Hateg locality, Hunedoara district.Species taken in study were: the Romanian local species and Marfona Dutch species. Between the two species of potato taken in study, the Marfona Dutch species was the one with a bigger sensibility to the attack of Colorado being obviously preferred by it. Taken in view the two regions with different weather conditions, the pest density was higher to the plain (Timisoara locality), than to the hill (Hateg locality).In conclusion, we could say that the hill region was one more favorable for potato culture than the plain region because it wasn't a place with a highest risk for the attack of Colorado beetle, and the damages produced weren't too high for the culture; and so far the species cropped, were better to the culture of Romanian local species because was more resistant to the beetle attack comparative with the Dutch species, which was more sensitive.