Obuolinio pjūklelio (Hoplocampa testudinea Klug) populiacijos tankis ir žalingumas soduose Lietuvoje, įvairių veislių obelis auginant pagal dvi ūkininkavimo sistemas

Abstract

An investigation of apple sawfly (Hoplocampa testudinea Klug 1816) (Hymenoptera: Symphyta: Tenthredinidae) populations was conducted in conventionally and organically managed apple orchards of Institute of Horticulture of Lithuanian Research Centre for Agriculture and Forestry in 2010–2013. The aim of this investigation was to examine population density of apple sawfly in conventionally and organically managed apple orchards by means of white sticky traps Rebell®Bianco, determine relationship between population density and infestation levels of fruits, and evaluate susceptibility of various apple cultivars to this pest. Density of apple sawfly populations varied considerably between years, management systems and apple cultivars. Strong or moderate dependence of infestation on trap catches was determined in six out of seven cultivars studied in organic orchard. In conventional orchard cultivars ‘Noris’, ‘Auksis’ and ‘Lobo’ suffered significantly higher damage and cultivars ‘Lodel’, ‘Ligol’ and ‘Spartan’ could be attributed to a moderately susceptible group of cultivars. Reliable damage levels could not be determined for conventional orchard. In organic orchard, cultivars ‘Aldas’, ‘Rubinola’, ‘Rajka’, were classified as highly susceptible, ‘Lodel’ and ‘Vitos’ – as moderately susceptible and 1 cultivar – ‘Enterprise’ as of low susceptibility. Control thresholds for six cultivars was defined at 5% infestation level: ‘Aldas’ – 13 sawfly trap-1, ‘Rubinola’ – 11 sawfly trap-1, ‘Vitos’ – 23 sawfly trap-1, ‘Lodel’ – 21 sawfly trap-1, ‘Rajka’ – 11 sawfly trap-1 and ‘Enterprise’ – 34 sawfly trap-1. No reliable damage threshold for hybrid No. 18501 was determined.