Influence of female cones on the vegetative growth of Pinus contorta trees

Branches of Pinus contorta Dougl. bearing two-year-old female cones initiated fewer lateral buds than vegetative branches. However, the number of lateral shoots that differentiated and grew was not reduced on female cone-bearing branches. Neither the number nor the weight of female cones influenced the length of the terminal shoot. The total length of all lateral shoots was positively associated with the weight of two-year-old female cones. Branch units with two-year-old female cones produced significantly more total dry weight in the current year than vegetative branch units. There was, however, no significant reduction in the dry weight of terminal and lateral shoots. Branches bearing female cones allocated between 17 and 45% of the current year's dry weight to two-year-old cones and between 1 and 5% was allocated to one-year-old female cones. Female cones therefore apparently do not reduce the photosynthetic potential of trees. The influence of female cones compared with male cones on the growth of trees is discussed.     

Assessing seed desiccation responses of native trees in the Caribbean

New Forests - Native trees from the Caribbean were tested for seed desiccation responses, by adapting the “100-seed test” protocol. Ninety-seven seed lots of 91 species were collected...     

Control of Lophodermium and Phacidium needle cast and Scleroderris canker in Pinus silvestris

Cycloheximide and a mixture of chlorothalonil and cycloheximide gave acceptable control of Lophodermium pinastri as well as of Phacidium infestans and Scleroderris lagerbergii on Pinus silvestris. The recommended number of sprays per year is one and four respectively.     

Modelling agroforestry systems of cacao (Theobroma cacao) with laurel (Cordia alliodora) and poro (Erythrina poeppigiana) in Costa Rica

The agroforestry systems of cacao (Theobroma cacao) under laurel (Cordia alliodora) and cacao under poro (Erythrina poeppigiana) were studied at CATIE, Turrialba, Costa Rica. An inventory was taken of the organic matter and nutrients (N, P, K, Ca, and Mg) separating the species into their compartments (leaves, branches, trunks and roots). Studies of the litter and of the mineral soil (0–45 cm) yielded these results: Patterns of nutrient accumulation are discussed in relation to the characteristics of these agroforestry systems.     

Butt rot in conifers caused by Serpula himantioides (Fr.) Karst.

Serpula himantioides was found to be a causal agent of butt rot in Douglas fir and Japanese larch in northern Germany. The decay started predominantly from tap roots and main side roots and extended few meters into the stem. In final stages of rot the basal heartwood was completely destroyed and the residual width of healthy sapwood was reduced. Laboratory tests revealed a tolerance by the fungus to extremely acid substrates.     

Die Wirksamkeit von Isomeren des Hexachlorcyclohexans gegen holzzerstörende Käferlarven

Zusammenfassung Es wurde die Giftwirknng der α-, β-, γ- und δ-Isomeren des Hexachlorcyclohexans gegenüber Eilarven des Hausbockk?fers (Hylotrupes bajulus L.) und mittelgro?en Larven des Gew?hnlichen Nagek?fers (Anobium punctatum De Geer) bestimmt. Gegenüber beiden Larvenarten erwies sich das λ-Isomere erwartnngsgema? als der bei weitem wirksamste Stoff. Danach folgt, je nach den Versuchsbedingungen um den Faktor 10 bis 20100 schlechter, unerwartet das α-Isomere. Das δ- und noch ausgepr?gter das β-Isomere sind bedeutend weniger wirksam. Der Unterschied gegenüber dem γ-Isomeren liegt für Hausbock-Eilarven in der Gro?enordnung von 1500 und 80000; für Anobien-Larven ist er mit < 500 geringer. Das Ergebnis mit dem α-Isomeren ist beachtenswert.

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Summary The toxicity of the α-, β-, γ-, and δ-isomers of hexachlorocyclohexane towards egg-larvae of the Old House Borer (Hylotrupes bajulus L.) and medium-sized larvae of the Common Furniture Beetle (Anobium punctatum De Geer) was determined. As was to be expected, the γ-,isomer proved by far most effective against both species of larvae. Then, unexpectedly, the α-isomer follows, inferior by the factor 10 to 2000 according to the testing conditions. The δ- and, even more distinctly, the β-isomer show a considerably smaller efficiency. The difference to the γ-isomer amounts to a relation of 1500 and 80000 withHylotrupes egg-larvae; it is smaller (<500) withAnobium larvae. The result obtained with the α-isomer is remarkable.

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Résumé L'effet toxique des α-, β-, γ-, et δ-isomères du chlorocyclo-hexane contre des ovule-larves desHylotrupes bajulus L. et contre des larves de moyenne grandeur del'Anobium punctatum De Geer fut déterminé. Comme supposé, le γ-isomère était bien la plus efficace substance. Inattendu, le α-isomère, suit, selon les conditions d'essai plus mauvaises du facteur 10 à 2000. Le δ-isomè re et plus distinctement le β-isomère sont efficaces beaucoup moins. La différence entre ces derniers et les γ-isomères est de 1500 et 80000 pour des larves deHylotrupes bajulus L.; elle e'st moindre (< 500) pour des larves del'Anobium punctatum De Geer.

     

Einige neue Erkenntnisse über die Bionomie der europäischen Monochamus-Arten (Col. Cerambyc.)1)

Ohne ZusammenfassungVortrag gehalten beim ersten Südtiroler Entomologentag in Dietenheim, 22. September 1970.I 39042 Brixen, Prov. Bozen/Italien, Rienzdamm 38     

The Effect of Gravity on Root Emergence from Cuttings of Some Tree Species

Poplar shoots trained horizontally and normally growing shootswere used to compare the effect of horizontal and vertical orientationin summer on the subsequent rooting of terminal cuttings; asignificantly greater number of preformed roots emerged fromcuttings of vertical shoots. This difference in rooting abilitymay be due to the lower concentration of indolyl-acetic acidin the upper than in the lower half of horizontal poplar stemsas shown by Leach and Wareing (1967). Decapitation of a seriesof these poplar cuttings (Populus ? robusta Schn.) showed thatwound-root production was influenced by the larger terminalbuds on vertical than on horizontal shoots. From a comparison of horizontal and vertical storage of applerootstock cuttings at 45 ?F in the autumn, 29 per cent moreof the horizontal cuttings than the vertical ones had a basalcallus in the following February. Of these cuttings which madesatisfactory shoot growth (over 5 cm) in the following summer,horizontal cuttings exceeded vertical ones by 80 per cent; aresult which was correlated with root production. In a second experiment with M II apple rootstocks in which cuttingswere both stored and grown at the same angle more roots occurredon cuttings placed horizontally rather than vertically, andthis orientation also induced the rootings of a greater proportionof leafy Worcester Pearmain apple cuttings.     

Integrated pest management of Tuta absoluta: practical implementations across different world regions

Journal of Pest Science - The South American tomato pinworm, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), has invaded most Afro-Eurasian countries and is threatening worldwide tomato...