Grison, P. 1984a La place des disciplines phytosanitaires dans la recherche forestière. [The place of plant protection disciplines in forest research.].. Comptes Rendus des Séances de l'Académie d'Agriculture de France 70(7): 827-834.

Notes: The necessity is stressed, with examples reviewed from the literature in France, of considering all the different biotic and abiotic components of a forest ecosystem and of cooperation between the different disciplines for assessing the impact of any single organism on the productivity of the forest and for controlling that organism. Plant protection investigations are stated to be justified when the balance of an ecosystem is upset by the introduction of a new arthropod (or of a tree variety susceptible to an arthropod already in the forest), by overcrowding or monocultures inviting heavy multiplication of the arthropod, or by sudden changes in the environment caused by climate or human activity which favour a particular species. Examples of insects that became pests in this way include Matsucoccus feytaudi, Cryptococcus fagisuga and scolytids, while Tortrix viridana was able to multiply because of its adaptability to natural selection pressures. The effects on tree physiology of attack by pests such as the pine processionary [Thaumetopoea pityocampa] or Diprion pini should be taken into account in considering integrated control measures, including biological control and selection of resistant or tolerant tree varieties.