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Articles by Erkki Annila

Category: Research article

article id 660, category Research article
Erkki Annila, Bo Långström, Martti Varama, Risto Hiukka, Pekka Niemelä. (1999). Susceptibility of defoliated Scots pine to spontaneous and induced attack by Tomicus piniperda and Tomicus minor. Silva Fennica vol. 33 no. 2 article id 660. https://doi.org/10.14214/sf.660
In 1990–1991, Diprion pini extensively defoliated Scots pine (Pinus sylvestris L.) trees in Lauhanvuori National Park in southwestern Finland. Many trees lost all their foliage, while others had ca. 10% foliage left after the second year of defoliation. Outside the national park, many nearby stands were also heavily defoliated in 1990, but were sprayed with diflubenzuron (Dimilin®) in 1991. This protected the current year needles, corresponding to ca 30% of full foliage. In spring 1992, pine trees with 0, 10, 30 and 100% foliage remaining (10 small and 10 large trees in each category) were baited with pine bolts to induce stem attacks by pine shoot beetles. All baited trees were attacked by Tomicus piniperda and some by T. minor. The attacks failed in all these trees except those that were totally defoliated and some of the small trees with 10% foliage left. Many unbaited trees escaped attack entirely, but only totally defoliated trees were successfully colonized (i.e. produced brood). Attack densities and brood production figures peaked in baited, large and totally defoliated trees. None of the measures (cambial electrical resistance, resin flow, induced lesion length by fungal inoculation, amount of hydrocarbons or phenolic compounds) used to describe tree vigour at the time of attack gave better information than the estimated remaining foliage. We conclude that the risk for beetle-induced mortality following defoliation is a function of remaining needle biomass and beetle pressure. Even at high beetle densities (as was simulated by baiting of trees), trees with 10% of the foliage remaining were able to defend themselves against attacking pine shoot beetles.
  • Annila, Finnish Forest Research Institute, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail: erkki.annila@metla.fi (email)
  • Långström, Swedish University of Agricultural Sciences, Dept of Entomology, P. O. Box 7044, S-750 07 Uppsala, Sweden ORCID ID:E-mail:
  • Varama, Finnish Forest Research Institute, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail:
  • Hiukka, Finnish Forest Research Institute, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail:
  • Niemelä, University of Joensuu, Faculty of Forestry, P.O. Box 111, FIN-80101 Joensuu, Finland ORCID ID:E-mail:

Category: Research note

article id 517, category Research note
Matti Huotari, Mareena Jaskari, Erkki Annila, Vilho Lantto. (2003). Responses of olfactory receptor neurons of the large pine weevil to a possible deterrent Neutroil® and two other chemicals. Silva Fennica vol. 37 no. 1 article id 517. https://doi.org/10.14214/sf.517
Electrophysiological responses of olfactory receptor neurons were measured from the antennal sensilla of large pine weevils (Hylobius abietis L.) at 1 s exposure to Neutroil®-hexane mixture odour as a possible deterrent chemical and, for comparison, to α-pinene, α-pinene-ethanol mixture, and ethanol odours, respectively. Neutroil® is a commercial chemical pulp-mill product which has been studied earlier as a deterrent for large pine weevils with preliminary feed tests. In addition, ethanol, hexane and clean carrier air responses were measured. Odour pulses and clean air, as a zero reference value, were directed at a fixed insect antenna in order to induce olfactory responses. Simultaneous olfactory responses, i.e. Hylobius electroantennograms (EAG) and action potential responses, were recorded and these responses of Hylobius olfactory receptor neurons (ORN), such as action potential rates, silent periods and EAG responses, were analyzed for all simultaneous recordings. The exposures to α-pinene, α-pinene-ethanol mixture, pure ethanol and hexane caused an increase of the action potential rate (up to 70 pulses per second) in the ORNs sensitive to these odours, while the Neutroil®-hexane mixture exposures caused either silent periods with a duration between 0.6 and 1.1 s for 1 s exposure pulses or they had no response at all in the ORNs sensitive to the other odours. Thus, the possible deterrence may be caused by inhibition of some pinene-alcohol ORNs.
  • Huotari, University of Oulu, P.O. Box 4500, FIN-90014 University of Oulu, Finland ORCID ID:E-mail: matti.huotari@oulu.fi (email)
  • Jaskari, University of Oulu, P.O. Box 4500, FIN-90014 University of Oulu, Finland ORCID ID:E-mail:
  • Annila, Finnish Forest Research Institute, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail:
  • Lantto, University of Oulu, P.O. Box 4500, FIN-90014 University of Oulu, Finland ORCID ID:E-mail:

Category: Article

article id 5442, category Article
Erkki Annila, Kari Heliövaara. (1991). Chemical control of cone pests in a Norway spruce seed orchard. Silva Fennica vol. 25 no. 2 article id 5442. https://doi.org/10.14214/sf.a15596

The effect of three pesticides containing either dimethoate (0.5% a.i.), permitrin (0.5%) or triadimephon (0.5%) on the cone pests and flowering biology of Norway spruce (Picea abies (L.) H. Karst.) was tested in a seed orchard in mid-May or in the beginning of June. The pesticide treatments significantly reduced infestation by Laspeyresia strobiella and Kaltenbachiella strobi only. Variation in the number of cones infested by both insects and cone rusts was high between the spruce clones. Generally, the pesticides did not affect flower viability, seed quality or seed germination, but reduced drastically the germination capacity of pollen in vitro. In practice, sufficient control cannot be achieved with concentrations or methods used in the present study.

The PDF includes an abstract in Finnish.

  • Annila, ORCID ID:E-mail:
  • Heliövaara, ORCID ID:E-mail:
article id 5393, category Article
Erkki Annila. (1989). Metsien kunto ja bioottiset tuhonaiheuttajat. Silva Fennica vol. 23 no. 4 article id 5393. https://doi.org/10.14214/sf.a15551
English title: Condition of forests and biotic damages .

This review discusses whether forests are affected by biotic damages due to present or future environmental disturbances, and do environmental threats, such as air pollution and climatic change, weaken the condition of forest in a way that makes them vulnerable to damages by fungi and insect. The defence mechanisms of trees and factors affecting the development of an outbreak are described. Finally, the ways that air pollution and climatic change may affect biotic damages are discussed. 

  • Annila, ORCID ID:E-mail:
article id 5197, category Article
Kari Heliövaara, Erkki Annila, Eero Terho. (1983). Effect of nitrogen fertilization and insecticides on the population density of pine bark bug, Aradus cinnamomeus (Heteroptera, Aradidae). Silva Fennica vol. 17 no. 4 article id 5197. https://doi.org/10.14214/sf.a15180

The effect of nitrogen fertilization and two insecticides on the occurrence of the plant pine bark bug, Aradus cinnamomeus Panzer, was investigated in a young Scots pine (Pinus sylvestris L.) stand in Southern Finland. Three years after the treatment the bug density was lowest in the trees treated with lindane or dimethoate. However, in spite of the increasing height growth of the trees, they did not grow significantly faster than the control trees. Nitrogen fertilization increased both bug density and the height growth of the trees. Thus, the value of nitrogen fertilization against Aradus cinnamomeus remains obscure.

The PDF includes a summary in Finnish.

  • Heliövaara, ORCID ID:E-mail:
  • Annila, ORCID ID:E-mail:
  • Terho, ORCID ID:E-mail:

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