Pheromone based monitoring and control of pine sawflies

Every year large areas of forest are defoliated by the larvae of various insects. One of the most important insect groups causing damage on pines (Pinus  spp.) is the members of the family Diprionidae (conifer or pine sawflies). Many years, several hundred thousand hectares are damaged by pine sawflies in Europe. If other regions with extensive areas of pine forests are considered, i.e. Asia and North America, the area of damage increases several times. The most important effect of pine sawfly defoliation is reduced growth of the trees. A normal pine sawfly outbreak (period with harmful population densities) lasts 3 - 4 years and causes a 33% reduction in growth over a ten-year period. This is equal to three normal annual increments and corresponds, on reasonable good sites, to an economical loss of about 500 US$ per hectare. For monitoring sawfly densities, egg or cocoon sampling is done, which is time and labour consuming and not always reliable. To control outbreaks, various insecticides are used, with well known drawbacks, such as killing beneficial insects (e.g. natural enemies of pine sawflies), contaminating the natural environment and challenging human health.

This project aims at improving the monitoring and control methods of pine sawfly populations in order to decrease economical losses and usage of insecticides. This will be accomplished by exploiting the chemical communication system of the insects, i.e. by using species specific pheromones (odorous signal substances). For many other pest insects pheromones are used for population monitoring or for management of outbreak populations. For pine sawflies, development of such methods was delayed mainly due to chemical problems connected with the identification and synthesis of the pheromone components. These problems have recently been solved by some of the collaborators of this project, and the first studies aimed at practical applications of pine sawfly pheromones have been
undertaken with some of the species.

Three objectives can be distinguished:
1. To identify the sex pheromones of the species not yet studied from this perspective. This involves e.g. insect rearing, chemical analysis, chemical synthesis and physiological and behavioural studies.
2. To develop methods for early detection of sawfly presence, for monitoring population densities and for assessing the risk of outbreaks. This involves e.g. forest site documentation, insect trapping and statistical analysis.
3. To develop effective, sustainable and environmentally friendly methods for managing outbreak population levels. This involves e.g. dispenser technology and site documentation.

During three years, feb 1996 to Jan 1999, the research was done within an international and interdisciplinary project supported by the European Community and coordinated by Olle Anderbrant. The project title is "Pine sawfly pheromones for sustainable management of European forests", the acronym is PHERODIP, and more information is available on the PHERODIP homepage.

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Page created 95-10-29. Updated 01-01-15.
Text:  Olle Anderbrant, Dept. of Ecology, Lund University, S-223 62 LUND, Sweden.
Webmaster:  Erling V. Jirle, Dept. of Ecology.