Comparison of Ips cembrae (Coleoptera: Curculionidae) Capture Methods: Small Trap Trees Caught the Most Beetles

Ips cembrae is the most important bark beetle pest of larches and has had several local outbreaks in recent decades in Europe. In this study, we compared the numbers of I. cembrae captured by pyramid-trap piles, trap trees, pheromone traps, and poisoned and baited tripods. We also studied how the properties of trap trees and trap logs (volume, sun exposure, and position relative to the ground once deployed) affected the trapping of I. cembrae. We found that both sexes avoided infestation at the bottom of the logs and more than 15 times the number of beetles were captured by traditional trap trees than by pheromone traps or baited and insecticide-treated tripods. The number of I. cembrae per trap tree did not decrease with trap volume; therefore, it is appropriate to use traps of small dimensions. Baited tripods, pyramid-trap piles, and pheromone traps could be useful for detection of the beginning of flight activity, but trap trees are the most useful for reducing I. cembrae numbers.

Comparison of phoretic mites associated with bark beetles Ips typographus and Ips cembrae from central Croatia

Na nekoliko lokacija u Hrvatskoj (Nova Gradiška, Koprivnica, Gospić i Jastrebarsko) sa različitih vrsta drveća (Picea abies, Larix decidua i Pinus sylvestris) sakupljani su različiti stadiji ariševog potkornjaka, Ips cembrae i smrekinog pisara, Ips typographus te supstrat iz njihovih hodnika u svrhu sakupljana i identifikacije foretičkih grinja. Izravno sa tijela potkornjaka determinirano je 4 vrsta grinja: Iponemus gaebleri (Tarsenomidae), Histiostoma piceae (Astigmata, Histiostomatoidea), Dendrolaelaps quadrisetus (Gamasina) i Urobovella sp. (Uropodidae). Iponemus gaebleri bila je najčešća nađena vrsta kod obiju vrsta potkornjaka. Tri druge vtrste sakupljene su izravno iz hodničkih sustava. Istraživana su i mjesta spajanja foretičkih grinja s potkornjacima. Iponemus gaebleri i D. quadrisetus tako se najčešće nalaze na obronku zadka, dok se foretičke deutonimfe porodice Histiostomatidae obično nalaze na ventralnoj strani prsišta. Statističkom anlizom potvrđen je jasna preferencija I. gaebleri na I. cembrae. Mladi još nezreli kukci Ips cembrae, koji izlaze iz materinjih hodnika nose signifikantno više foretičkih grinja nego roditeljski. Ženke neidentifcirane vrste roda Histiostoma nađene su u hodnicima I. typographus. Grinje su uglavnom bile pokrivene s većim brojem neidentificiranim sporama gljiva iz skupine Ascomycota (Hypocreales). U radu se daje dihotomski ključ za identifikaciju larvi i protonimfi za porodicu Histiostomatidae.

Large larch bark beetle Ips cembrae (Coleoptera: Curculionidae, Scolytinae) in the Czech Republic: analysis of population development and catches in pheromone traps / Lýkožrout modřínový Ips cembrae (Coleoptera: Curculionidae, Scolytinae) v České republice: analýza vývoje populací a vzorků z feromonových lapačů

The paper summarises available data on the occurrence of Ips cembrae in the Czech Republic and analyses the effect of temperature and precipitation on its population growth; compares numbers of beetles of overwintering and offspring generation, and compares the proportion of females and males caught in pheromone traps. The analysed data of the Forestry and Game Management Research Institute about the volume of harvested wood infested by I. cembrae from 1994 to 2013 varied between 150 and 1,415 m3. During the entire study period I. cembrae attacked more than 0.5 m3 per ha of larch forest stands in only four districts. Temperatures over the period from March to October, from April to June and annual average temperatures during the preceding and actual years, and the ratio of the annual rainfall to long-term rainfall average obtained from the Czech Hydrometeorological Institute had no significant effect on the population growth. Adults were also caught with pheromone traps, in which two generations were documented. In 2013, the numbers of caught beetles of the offspring generation exceeded those of the overwintering generation. This was due to warm and dry weather and, probably also due to high reproductive success. Although more females were caught by pheromone trapping, numbers of males and females did not differ significantly. During the studied period several periods of local outbreak of I. cembrae occurred in the Czech Republic, but their causes remained unclear, although the increase of bark beetles populations is generally regarded as a result of hot and dry weather. Larch bark beetle represents only a marginal problem in the Czech Republic.

The larch bark beetle Ips cembrae (Heer) (Coleoptera, Curculionidae, Scolytinae) in young and older larch stands of southern Poland

Kornik modrzewiowiecIps cembrae(Heer) (Coleoptera, Curculionidae, Scolytinae) w młodnikach i starszych drzewostanach modrzewiowych południowej Polski