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Possibilities for biological control of velvetleaf (Abutilon theophrasti Medi.) with phytophagous insects

Velvetleaf (Abutilon theophrasti Medik.) creates a serious weed problem in farmland, in Croatia especially in maize, soybean, sugar beet and sunfl owercrops, but worldwide as well. Because of early-season control escape, and the discovery of atrazine-resistant populations of velvetleaf, investigation of insects as potential biological agents for velvetleaf control was conducted in Croatia from 1995 to 2000. In 24 Croatian localities a total of 15 insect species associated with velvetleaf were recorded. A total of 10 insect species: Carpocoris purpureipennis De Geer, 1773, Graphosoma lineatum italicum Müler, 1766, Lygeaeus saxatilis Scopoli, 1763, Pyrrhocoris apterus Linnaeus, 1758, Rhopalosiphum padi Linnaeus, 1758, Macrosiphum euphorbiae Thomas, 1878, Podagrica menetriesi Falderman 1837, Psylliodes brisouti Bedel, 1898, Carcharodus alceae Esper, 1780 and Autographa gamma Linnaeus, 1758, were recorded on velvetleaf for the fi rst time. The insect species Pyrrhocoris apterus, Carpocoris purpureipennis, Graphosoma lineatum italicum, Lygaeus saxatilis and Psylliodes brisouti were recorded on velvetleaf as accidentals and no signs of their feeding on velvetleaf were registered. Well known pest species Aphis fabae Scopoli, 1763, Rhopalosiphum padi, Macrosiphum euphorbiae, Autographa gamma and Ostrinia nubillalis Hübner, 1796 were recorded on velvetleaf rarely, but the feeding of the mentioned Lepidoptera species was recorded during fi eld observations. Frequently collected insect species Liorhyssus hyalinus Fabricius, 1794 f. hyalina, pallida and rubricata, Crocidosema plebejana Zeller, 1847 and Heliothis armigera Hübner, 1808 had a great impact on seed survival, while Podagrica menetriesi and Carcharodus alceae reduced the leaf area of velvetleaf significantly.

Abutilon theophrasti; biological weed control; Croatia; phytophagous insect fauna; velvetleaf

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