Occurrence, biology and harmfulness of Galerucella lineola (F.) (Coleoptera, Chrysomelidae) - Part 2. Larvae and this year's beetles

Abstract

The second part of the paper deals with the development and harmfulness of larvae and maturation feeding of this year’s beetles of <I>Galerucella lineola</I> (F.) before leaving for winter habitats. Embryogenesis takes on average 12 (in the laboratory 9) days. In the area of Žďár situated at a higher and colder location, larvae of the alder biological form occur on <I>Alnus glutinosa</I> and <I>A. incana</I> from June to August. In the warmer lowland area of Brno, larvae of the willow form occur on <i>Salix triandra, S. viminali</I>s and <I>S. caprea</I> from the 3<sup>rd</sup> decade of May to the beginning of August. In the laboratory, larvae of the alder form developed on average 16 days and larvae of the willow form 13 days. Larvae of the alder form damage on average 9.7 cm<sup>2</sup> leaves of <I>A. glutinosa</I> and larvae of the willow form 6.0 cm<sup>2</sup> leaves of <I>Salix caprea</I>. This year’s imagoes occur in the area of Žďár on alders from mid-July to the end of October and during 3 weeks, they damage on average 16 cm<sup>2</sup> leaves of <I>A. glutinosa</I>. This year’s imagoes occur on willows in the area of Brno from the end of June to the end of August. During 2 weeks, they damage on average 12 cm<sup>2</sup> leaves of <i>S. caprea</I>. The chrysomelid development is univoltine (in southern parts of Moravia partly bivoltine). The alder biological form of <I>G. lineol</I>a produced 2 (the willow form even 4) incomplete generations in the laboratory. This year’s imagoes damaged on average 36.6 cm<sup>2</sup> of <I>S. caprea</I> and laid 122 to 887 (on average 528) eggs. In the area of Brno, imagoes of the willow form were up to 65% parasitized by <I>Medina collaris</I> (Fall.) (Tachinidae).Tachinidae).