Modalité?infection des pins sylvestres par ĽArmillariella mellea (Vahl.) Karst dans les cultures forestières

Infection patterns in Scots pine plantations by Armillariella mellea (Vahl.) Karst. Macro- and microscopic analyses of Scots pine root systems in plantations infected by Armillariella mellea are described. Forms of infection and states of penetration are determined and correlated with resistance reactions. Variation of Armillariella attack is discussed in connection with the variation within the population of the host plants and parasites.     

Influence de la mycorhization et de la fertilisation sur le comportement de jeunes plants d'érable sycomore (Acer pseudoplatanus Link.)

Influence of mycorrhizae and fertilization on Acer pseudoplatanus seedlings . A greenhouse experi-ment compared growth and mineral nutrition of Acer pseudoplatanus seedlings on two soils with different fertilizations and with different endomycorrhization treatments. A strain of Glomus mosseae and a mycorrhizal complex from an A. pseudoplatanus stand prove to be much more growth efficient than the natural inoculum of the soils, mainly by improving phosphorus nutrition. These effects are additive to those of fertilization. This last result suggests that controlled mycorrhization can be of great practical interest even on rich soils.     

Méthode ?estimation de la hauteur de pourriture dans le tronc des épicéas sur pieds attaqués par le Fomes annosus (Fr.) Cooke

Estimating the height of decay in standing Norway spruce attacked by Fomes annosus (Fr.) Cooke. A method is given for estimating the height of decay due to Fomes annosus in standing Norway spruce. A good correlation is provided by the height of the decay and, at the 1,30m level, the diameter and stage of the decay. The data were obtained using Pressler borings.     

L'effet d'acides gras sur la stimulation des périthèces de Ceratocystis ips,C. minor et C. capillifera

The effect of fatty acids in stimulating production of perithecia of Ceratocystis ips, C. minor and C. capillifera. Perithecia formation of three species of Ceratocystis is stimulated by somo unsaturated fatty acids, spccially linoleic acid, and one saturated fatty acid (arachidic acid).     

Remarques sur la Diapause et le Cycle deCassida deflorata Suff.(Col. Chrysomelidae)

Ohne Zusammenfassung     

Accumulation de polluants organiques (H.P.A.) dans les horizons humifères des sols

Accumulations of organic pollutants (PAH) in organic layers of soils.—Possible relation with forest decline . Analysis of the upper levels of the organic layers of forest soils demonstrate a new kind of bioaccumulation leading to high level of contamination with polycyclic aromatic hydrocarbons (P.A.H.).     

Influence des sels fondants sur les arbres et autres végétaux Rapport présentéà la division Forêts de la Commission des Communautés européennes à Bruxelles

Effect of thawing salts on trees and other vegetation . Report to the Forestry Department of the Commission of the European Communities at Brussels. The effects of the chemical composition, the quality, the consumption and the sequences of application of thawing salts, on the soil, on trees and on other vegetation are described. Some conclusions and recommendations are given.     

Comparaison de deux méthodes d'identification des clones chèz le Basidiomycete parasite Armillaria obscura (syn: A. ostoyae)

Two methods were compared intending to distinguish between the clones of the root-rot fungus Armillaria obscura (syn. Armillaria ostoyae) in nature: one based on the pairing of the diploid isolates in pure culture, the other using the incompatibility alleles as genetic markers. As A. obscura fruits easily in vitro, both methods could be used for any type of diploid isolate whatever its origin. The two methods were quite superposable and defined the same clones. Artificial diploids issuing from the same fruitbody and isogenic for the incompatibility alleles appeared to belong to the same clone in pairing tests.     

La pourriture des faines causfée par Rhizoctonia solani Kühn: Incidence de cette maladie après les fainées de 1974 et 1976. Traitement curatif des faines en vue de la conservation

Rot of beechnuts caused by Rhizoctonia solani Kühn. Disease incidence after the 1974 and 1976 mast years. Curative seed treatment before storage. Rot of beechnuts by Rhizoctonia solani Kühn, occurred throughout French beech forests after the masts of 1974 and 1976. The site conditions and the climatic conditions of November and December determine the incidence of disease which is notably reduced by soil cultivation before the mast. Thermotherapy - 24 hours at 36–38°C at 100 % relative humidity - was shown to be a curative treatment of seeds before storage.