It is known that Colorado potato beetle rapidly develop resistance to a particular type of insecticide, so the alternative methods to control the CPB is becoming more important. Because of negative impacts on environment, not targeted activity, pest resistance to pesticides and strict environmental politics, researchers are looking for new, more environmental friendly ways to protect plants from pests. One such step is testing plant extracts to control the economically important pests in agriculture. In laboratory experiment, we studied the insecticidal activity of water extracts from selected non-native plants: Japanese knotweed (Fallopia japonica [Houtt.] Ronse Decr.)), Bohemian knotweed (Fallopia x bohemica (Chrtek & Chrtková] Bailey, tree of heaven (Ailanthus altissima [Mill.] Swingle), Canadian goldenrod (Solidago canadensis L.), giant goldenrod (Solidago gigantea Aiton), staghorn sumac (Rhus typhina L.) and indigo-bush (Amorpha fruticosa L.) for control of CPB. Of all the seven invasive plants, the best result was shown the tree of heaven, mortality of L1/L2 larvae was 68 ± 10,1%. Extracts had a greater effect on young larvae than on adult. Water extracts of non-native plants has greater impact when used as a systemic control (beetle mortality in the contact mode of control with invasive plants was up to 20 ± 6,3 % ). However this does not mean, that they could be used to protect potato plants against the CPB, as the insecticide was still the one with the highest mortality of the beetle (100 ± 0 % ).
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