Occurrence of gypsy moth (Lymantria dispar L.) in the Slovak Republic and its outbreaks during 1945–2020

Milan Zúbrik,Peter Zach,Marek Barta,Jan Liška,Andrej Gubka,Juraj Galko,Christo Nikolov,Ján Kulfan,Roman Leontovyč,Andrej Kunca,Zuzana Sitková,Jozef Vakula,Jaroslav Holuša,Bohdan Konôpka,Michal Lalík,Valéria Longauerová,Slavomír Rell

doi:10.2478/forj-2021-0007

Abstract

Abstract The gypsy moth is one of the most serious pests in forests and fruit tree plantations over prevailing parts of the Northern Hemisphere. This work is based on a literature review, and presents history of gypsy moth Lymantria dispar L., observed in Slovak forests within the period 1945–2020. The life cycle, hosts, natural enemies, population dynamics of pests, impact of outbreaks on forests and different management methods used in the past are discussed. Since 1945, there were nine gypsy moth outbreaks in Slovakia. Between 1945 and 2020, a total of 155,034 ha of deciduous forests were touched with varying intensity, representing an average annual damage of 2,040 ha. The strongest outbreak culminated in 2004. Totally 51,479 ha were attacked in the period of 2000–2008. We have found outbreak periods that repeat with frequency of 7.8 ±2.2 years and the average outbreak phase lasts 3.1 ±1.1 years. The period between two subsequent outbreaks seems to be more or less constant and duration of the outbreak phase seems to be gradually shortened during the study period. Several factors influencing the gypsy moth population dynamics in Slovakia are discussed. The role of biological control by using entomopathogenic fungus Entomophaga maimaiga is described.

Highlights

The gypsy moth Lymantria dispar L. (Lepidoptera: Erebidae) is one of the most serious forest insect pests, and of fruit trees across much of the Northern Hemisphere
It can be assumed that due to E. maimaiga, gypsy moth outbreaks should reach a lesser intensity in the future and be more local compared to the past
We have found outbreak periods that repeat with frequency of 7.8 ± 2,2 years and the average outbreak phase lasts 3.1 ± 1,1 years

Summary

Introduction

The gypsy moth Lymantria dispar L. (Lepidoptera: Erebidae) is one of the most serious forest insect pests, and of fruit trees across much of the Northern Hemisphere. The gypsy moth ranked among key insect pests that feed on leaves in forests of Slovakia during the study period, along with Operophtera brumata L., Erannis defoliaria Clerck, Agriopis leucophaearia Denis & Schiffermüller, Tortrix viridana L., Orthosia spp., Choristoneura murinana Hübner, Epinotia nigricana Herrich-Schäffer, Diprion pini L., Diprion spp., Melolontha spp., and some other species (Turček 1956; Charvát & Patočka 1960; Čapek 1961; Patočka 1955, 1963a, b, 1967a, 1973; Leontovyč et al 1980; Surovec et al 1989; Zúbrik 2006; Zúbrik et al 2015, 2017a, b; Vakula et al 2015; Sarvašová et al 2020) Some species, such as Pristiphora laricis Hartig, Rhyacionia buoliana Denis & Schiffermüller or Coleophora laricella Hübner, have caused damage to trees only occasionally and only in relatively restricted areas (Leontovyč et al 1980; Surovec et al 1989; Zúbrik et al 2017b)

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