DEFINITION OF METHODS TO PROTECT CONIFERS FROM INSECTS COMPROMISING FOREST SURVIVAL AND REGENERATION IN THE MOUNTAIN AREAS OF SOUTHWESTERN CHINA

OBJECTIVES

The main objectives are as follows:

• To understand the reasons why the bark beetle Tomicus piniperda causes heavy damage in Yunnan pines (Pinus yunnanensis), while its economic impact stays at low level in Europe.
• To establish an inventory of the main cone and seed insects in Yunnan and to study their relations with host trees.
• To measure the incidence of seed damage by insects and assess the effect on the natural regeneration of the main conifer species in Yunnan.
• To define integrated control methods against T. piniperda and the main cone pests in Southwestern China.
• To define conditions to be respected in Europe, to avoid T. piniperda to become dangerous.
• To train Chinese scientists and engineers to research and control techniques on forest pests, and to enlarge the European experience in that field.

ACTIVITIES

The key activities envisaged are:

• Comparison of T. piniperda ecology in China and in Europe, by focusing on the shoot feeding part of the beetle life cycle (beetle dispersal, attraction).
• Identification of the phytopathogenic fungi associated with T. piniperda and definition of their role in beetle population establishment. Measurement of their frequency, their aggressiveness and pathogenicity.
• Tree death mechanisms: relative role of the beetles and the fungi in tree death, and importance of the localisation of the attacks (crown or trunk).
• Measuring P. yunnanensis natural resistance to bark beetles and their associated fungi, and describing the phloem induced reaction and its effect on aggressors. Defining the relations with the level of shoot damage.
• Examine, with both a field survey and an experimental approach, the relations between water stress, bark beetle damage and tree resistance.
• Identification, biology and damage assessment of insects attacking conifers of afforestation, by sampling of cones throughout the range of various conifer species. Identification of the damaging insects species and comparison with the European ones attacking similar host trees.
• Analysis of tree odors at the time of cone attack. Laboratory and field tests on insect response to volatiles. Identification of insect sex pheromones and field tests with insects.

EXPECTED OUTCOME

Explanation of the reasons for the damage by T. piniperda in SW China. Generality of the European model of conifer-bark beetle-fungi relationships. Definition of targets for control of bark beetle damage in SW China. Definition of possible attractants. Definition of possibilities to improve tree resistance. Elaboration of bark beetle risk prediction models. Inventory and incidence of cone and seed insects on conifer forests of SW China. Definition of attractive visual traps baited with volatiles for cone and seed insects. Finally, proposition of integrated control methods against bark beetles and cone and seed pests in SW China.