Forest Pathology

Capretti, P.; Mugnai, L.

doi: 10.1111/j.1439-0329.1989.tb00261.xpmid: N/A

Heterobasidion annosum shows a greater colonization ability in wood interred in pastureland soil than in forest (beech and silver fir stand) soils. Its behaviour is studied in relation to wood colonization by other fungi present in the different soils.

Gramss, G.

doi: 10.1111/j.1439-0329.1989.tb00262.xpmid: N/A

In standing or freshly excised stemwood of European beech and several other hardwoods with nontoxic cores the resistance to the ingress of decay fungi increased with the vitality status of the living parenchyma cells in both sap‐ and heartwood. Virtually no influence on the timber's decay resistance could be ascribed to wide fluctuations in the content of phenolics, to regional moisture distributions, and to synergistic or antagonistic actions of first‐generation bacteria that precede the fungal invasion.

Kamp, B. J.

doi: 10.1111/j.1439-0329.1989.tb00263.xpmid: N/A

Scots pine was much less susceptible (percent of seedlings infected) to western gall rust from the coast of British Columbia than lodgepole pine. There was no difference in the virulence spectrum of rust collections from Scots and lodgepole pine. Scots pine could be readily divided into susceptible (heavily infected) and resistant (disease free) seedlings; infection on lodgepole pine varied in a continuous and unimodal fashion.

Tesche, M.; Feiler, Sonja; Michael, Gerda; RANFT, H.; Bellmann, Christa

doi: 10.1111/j.1439-0329.1989.tb00264.xpmid: N/A

Physiological reactions of spruce (Picea abies) on complex SO2‐ and drought‐induced stress. Part 1: Reactions caused by simultaneous effect of SO2 and drought. To indicate stress a certain number of physiological and biochemical parameters were used on young spruces. Simultaneous SO2 and drought‐induced stress under the given stress intensities leads to a reduction in the SO2‐uptake, whereby the stress effect is somewhat reduced as compared with SO2‐stress alone. The parameters used for the indication of stress show synergistic, antagonistic as well as superimposing types of reactions.

Michael, Gerda; Tesche, M.; Feiler, Sonja; Ranft, H.; Bellmann, Christa

doi: 10.1111/j.1439-0329.1989.tb00265.xpmid: N/A

Physiological reactions of spruce (Picea abies) on complex SO2‐ and drought‐induced stress. Part 2: Responses of drought‐induced spruces to subsequent SC2‐stress. Changes in the reactivity of spruce saplings to SO2‐stress as a result of preceding sublethal drought‐induced stress were investigated. Of the tested physiological and biochemical parameters some values of water balance still reflected the drought‐induced stress. The drought‐induced response of the saplings to SO2 became particularly obvious in an increase of the osmotic potential. A stressreducing effect of the preceding drought on the response of young spruces to SO2 could not be observed.

Singh, Pritam; Carew, G. C.

doi: 10.1111/j.1439-0329.1989.tb00266.xpmid: N/A

Eastern dwarf mistletoe, Arceuthobinm pusillum, is known in Newfoundland since 1902. However, it has recently become very conspicuous and damaging in some parts of the island, and is regarded as one of the principal agents damaging black spruce on the island. The mistletoe has been found to reduce volume through tree and branch mortality, decline in growth, and cone and seed production, cause alterations in nutrient contents, and induce malformation of stem.

Osswald, W. F.; Benz, B.

doi: 10.1111/j.1439-0329.1989.tb00267.xpmid: N/A

Picein can quickly be converted into p‐hydroxacetophenone by endogenous glucosidases activated by freezing and thawing of spruce needles. Picein was the main component of all investigated spruce needles. Its contents varied between 4 and 30 mg/g fw whereas p‐hydroxyacetophenone (pHAP) concentrations between 0.2 and 0.6 mg/g fw were found. No significant difference for picein and pHAP contents were observed comparing green and bleached needles or needle segments. In each case the ratio of pHAP to picein was smaller than one for both green and bleached needles. The importance of pHAP for pigment bleaching is discussed.

Siepmann, R.; Leibiger, Marion

doi: 10.1111/j.1439-0329.1989.tb00268.xpmid: N/A

On the host‐specification of Armillaria species.

Wu, W. D.; Jeng, R. S.; Hubbes, M.

doi: 10.1111/j.1439-0329.1989.tb00269.xpmid: N/A

The toxic effect of elm phytoalexins (mansonones) on two isolates of Ophiostoma ulmiwas studied cytologically and physiologically. The effects included increasing ion leakage, reducing respiration rate and altering the structure of cellular organelles.

Nelson, E. E.

doi: 10.1111/j.1439-0329.1989.tb00270.xpmid: N/A

Sublethal fumigation followed by introduction of biological control agents may offer a method of controlling laminated root rot [Phellinus weirii (Murr.) Gilb.]. To determine the tolerance of P. weirii and 9 Trichoderma spp. to 2 fumigants, culture tubes containing 47 isolates of these fungi were fumigated for 10 days with 12 concentrations of chloropicrin and Vorlex in sealed glass containers. Considerable variation occurred in tolerance to fumigant among isolates within a species and among species. Isolates of P. weirii, however, were more consistent and were less tolerant to the fumigants than were isolates of the other fungi. In general, isolates of all fungi appeared more tolerant of Vorlex than of chloropicrin.