Antibacterial activity of Salvia tomentosa essential oil.

The essential oil of Salvia tomentosa aerial parts, consisting of 1,8-cineol (17%), beta-caryophyllene (11%), cyclofenchene (10%) and delta-cadinene (6%), was screened for its antimicrobial activity. The essential oil remarkably inhibited the growth of tested Gram-positive and Gram-negative bacteria except for Pseudomonas aeruginosa.     

Field evidence for the large pine weevil,Hylobius abietis as a vector of Heterobasidion annosum

Mycological analysis of the excrements of adult weevils (Hylobius abietis L.), trapped in the baited pitfall traps in South Bohemia, Czechosovakia, demonstrated the presence of viable spores which suggest a positive role of the weevils as vectors of H. annosum.     

Bestandeszuwachs und Leistungsvergleich montan-subalpiner Lärchen-Fichten-Mischbestände

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Exploiting the potential of indigenous agroforestry trees: Parkia biglobosa and Vitellaria paradoxa in sub-Saharan Africa

Agroforestry Systems - Parkia biglobosa (néré) and Vitellaria paradoxa (karité) are indigenous tree species that are economically and socially important for local people in...     

Laboratory evaluation of some pesticides on the cabbage aphid,Brevicoryne brassicae L. and their side effects on some important natural enemies

The susceptibility of adults of the cabbage aphid,Brevicoryne brassicae and two of the most important predators,Coccinella undecimpunctata andChrysopa carnea to pesticides was assessed. Most of the organophosphorus and carbamate compounds tested were toxic to the aphids. Profenophos was highly toxic to the adult virginoparous aphid at Lc50 level. Malathion demonstrated the highest toxicity to, the aphids. The application of profenophos for the cabbage aphid at Lc50 level exhibited no toxicity forCoccinella but was highly toxic forChrysopa. Pirimicarb proved to be the most selective of the compounds tested for the control of aphids when it was used at a concentration that caused 50% mortality as it was found to be unharmful to bothChrysopa andCoccinella. Dimethoate, on the other hand, was found to be very harmful and highly toxic to bothCoccinella andChrysopa adults and would probably be destructive to those natural enemies in the field. Laboratory evaluation indicates that both pirimicarb and malathion have potentials for use, in IPM program for vegetable pest control.     

Influence of acidity on the growth of Trichoderma viride Pers. ex Fr. and on the inhibitory effect of its filtrates against Fomes annosus (Fr.) Cke. in artificial cultures

This work reports results of observations on mycelial dry weight yield, pH changes and the inhibitory effect of filtrates of Trichoderma viride on linear growth of the mycelium of Fomes annosus. The maximum mycelial yield of T. viride, derived from spores was obtained within the pH range 2,5–3,1. The greatest inhibitory effect of filtrates on the mycelial growth of F. annosus occurred at an initial pH of the Trichoderma cultures from 2,0-3,5. At other pH-values, no inhibition was found.     

Inhibitory effect of Trichoderma viride Pers. ex Fr. filtrates on Fomes annosus (Fr.) Cke. In relation to some carbon sources

The mycelial yield of Trichoderma viride on a number of carbon sources and the inhibitory effect of its filtrates on Fomes annosus were investigated. d-Xylose and d-glucose as carbon sources in the media gave the highest degree of inhibition when their filtrates were directly tested against F. annosus mycelium. The protection of pine wood blocks with filtrates was most effective when these were derived from cellulose and d-xylose.     

Genetic variation in foliar nutrient concentration in relation to foliar carbon isotope composition and tree growth with clones of the F1 hybrid between slash pine and Caribbean pine

The objectives of this study were: (1) to quantify the genetic variation in foliar nutrient concentration in relation to foliar carbon isotope composition (δ¹³C) and tree growth of 122 clones of ca. 4-year-old F₁ hybrids between slash pine (Pinus elliottii Engelm var. elliottii) and Caribbean pine (P. caribaea var. hondurensis Barr. et Golf.) grown at two experimental sites with different water and nutrient availability in southeast Queensland, Australia and (2) to examine the potential of using foliar nutrient concentration of the 4-year-old tree canopies for selecting elite F₁ hybrid pine clones with improved nutrient-use efficiency (NUE) and water-use efficiency (WUE), and ultimately enhanced tree growth under ambient growing conditions. There were significant differences in foliar nutrient concentrations between two canopy positions (upper outer and lower outer canopy) sampled, between summer and winter, and between the two sites. This highlights that foliar nutrient concentrations are influenced by sampling and environment. Significant genetic variations in foliar nutrient concentrations were detected between the clones, between the female parents, and between the male parents of the clones in both sampling seasons at both sites. Depending on the nutrient concerned, canopy position, season, and site sampled, the clones accounted for 4.7–33.9% of the total variation in foliar nutrient concentrations, the clone female parents for 0–25.1% and the clone male parents for 0–28.6%. The site-by-clone interactions were statistically significant for foliar N, P, Mg, Cu, Zn, Mn, Fe and mineral concentrations at the upper outer canopy in summer, and for foliar N concentration in winter. There were significant, positive correlations between clone means of foliar δ¹³C and N concentration at the upper outer canopy in summer for the wet site, while clone foliar δ¹³C was also positively related to clone foliar N concentration at both canopy positions in summer for the dry site. This suggests that clone WUE as reflected in foliar δ¹³C may be improved by selecting elite clones with higher foliar N concentration and increased photosynthesis, leading to enhanced tree growth when both water and N are the major growth-limiting factors. This is supported by the positive correlation detected between clone tree height and foliar N concentration at the upper outer canopy for both sites. Thus, foliar nutrient (particularly N) concentration, together with foliar δ¹³C, may be useful for assisting in selection of exotic pine clones with improved NUE and WUE, and enhanced tree growth under the nutrient- and water-limiting environments.     

Carbon and nitrogen dynamics under windrowed residues during the establishment phase of a second-rotation hoop pine plantation in subtropical Australia

The dynamics of carbon (C) and nitrogen (N), derived from the decomposition of windrowed harvest residues, was examined in the establishment phase of a second rotation (2R) hoop pine (Araucaria cunninghamii Aiton ex A. Cunn) plantation in subtropical Queensland, Australia. Following harvesting and site preparation, when residues were formed into windrows, in situ N mineralisation was measured in positions along the three tree-planting rows formed between the windrows. The position above the windrow had a higher nitrification rate than the other positions, averaging about 18 kg N ha⁻¹/month compared with 12 and 9 Kg N ha⁻¹ for the positions between and below the windrow positions, respectively. This position also had consistently greater soil moisture.

Macroplots were formed extending 5 m above and 10 m below a windrow. Windrowed residues within the macroplots were replaced by ¹⁵N-labelled material comprising hoop pine foliage, branch and stem. Hoop pine trees were planted within each macroplot with foliar samples taken at 12 and 24 months. Differences in foliar ¹⁵N enrichment between positions within macroplots were <1‰. Soil samples were taken from positions along the macroplots at 6-monthly intervals. Samples revealed an initial release of labile C and N but soil δ¹⁵N showed that residue-derived N was largely immobilised within the windrows for the 30-month sampling period. Whilst the use of windrows may act as a barrier to the down-slope movement of water, the residue N within the windrows may not be available to the trees of the following rotation for a considerable period following planting. Trees closest to the windrows may be able to introduce roots under the windrows thereby gaining access to the available N, but trees in the central tree planting row are unlikely to derive any significant benefit from the decomposition of windrowed residues.