Experiments on Curative Low and Ultra-low Volume Spraying Against Dacus oleae Gmel.

Applications of 1, 2, 4, 6 and 12 lit. of spray per tree, each volume containing 6 g. of dimethoate a.i., did not show significant differences between the treatments, but olive fly pupae and third instar larvae were found to be more resistant than first and second instar larvae. Also, no differences became apparent between treatments with Dimecron 50, Carbicron 50 and Nuvacron 50 at rates of 7, 10 and 14 c.c. per tree respectively; these experiments will be continued.     

Note on the Control of Olive Fly (Dacus oleae [Gmel.]) by Means of Low and Ultra-low Volume Bait-spraying

In 1967, 1968 and 1969 the efficacy of aerial low volume and ultra-low volume bait-spraying against Dacus oleae (Gmel.) was compared in Greece. Results were mainly assessed by periodical trapping and by post-treatment countings of the percentage of attack in sampled olives. No difference between the effect of the two methods became apparent. It is deemed necessary, however, to repeat the experiments under conditions of heavier infestation.     

On the parafollicular cells in the thyroid gland of the bovine foetus

The thyroids of 117 bovine foetuses were studied by some histochemical and selective staining methods with respect to the occurrence of parafollicular cells. Furthermore, 7 foetuses were studied by electron microscopy. The length of the foetuses varied from 6 to 72 cm corresponding to an estimated age of about 2 to 9 months. Parafollicular cells were observed in the thyroids of all foetuses examined. The ultrastructure of the parafollicular cells in the foetuses differed very little from that described in adult animals. Histochemically, Luxol fast blue positive phospholipids and α-glycerophosphate dehydrogenase activity could be observed in the cells. The Solcia-Sampietro method gave positive results in most of the foetuses examined. The reactions observed at light microscopic level were rather faint in the youngest foetuses. The functional aspects of the results are discussed.     

Effect of gibberellic acid on sprouting,growth of internodes,tuber shape and yield in different varieties of potatoes

Summary Sprouting was hastened by one week by treatment for 5 min, with gibberellic acid (GA) at a concentration of 25 p.p.m. in newly dug potatoes ofUp-to-Date andVoran. A similar effect was noted inRoyal Kidney treated at a concentration of 50 p.p.m. Although some sprouting occurred within 7 days in treated tubers, 100% sprouting had not occurred until 21–36 days after treatment. There was increased extention of internodes following treatment with GA at concentrations of 25, 50 and 100 p.p.m. Treatment at 100 p.p.m. resulted in the greatest extention of internodes. At the higher concentrations the maximum extension occurred between internodes 4–6 inRoyal Kidney andVoran, and 4–7 inUp-to-Date. Treatment with GA had a depressing effect on leaf indices inRoyal Kidney andUp-to-Date whereas inVoran it had the reverse effect. In all varieties, yield in pot experiments was increased by treatment with GA at 100 p.p.m. for 90 min. All treated seed invariably produced deformed tubers the numbers of which increased with the concentration of GA.

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Zusammenfassung Das Auskeimen von frisch geernteten Kartoffeln der SortenUp-to-Date undVoran (Abb. 1 b und c) wurde durch Behandlung mit Gibberellins?ure (GA) (Eintauchzeit 5 Minuten, Konzentration 25 ppm) um eine Woche beschleunigt. Eine ?hnliche Wirkung konnte bei der SorteRoyal Kidney festgestellt werden, die mit GA in einer Konzentration von 50 ppm (Abb. 1 a) behandelt wurde. Obwohl einige der behandelten Knollen nach 7 Tagen austrieben, wurde 100%ige Keimung erst 21–36 Tage nach der Behandlung erreicht. Die Behandlung mit GA in Konzentrationen von 25, 50 und 100 ppm bewirkte eine Verl?ngerung der Internodien. Die Konzentration von 100 ppm verursachte die gr?sste Ausdehnung der Internodien. Bei der h?chsten Konzentration lag die gr?sste Verl?ngerung zwischen den Internodien Nr. 4-6 beiRoyal Kidney undVoran, zwischen 4–7 bei der SorteUp-to-Date (Tabelle). Behandlung mit GA hatte bei den SortenRoyal Kidney undUp-to-Date eine Verkleinerung des Blattindexes zur Folge, w?hrend beiVoran eine umgekehrte Wirkung hervorgerufen wurde (Abb. 2). Topfversuche ergaben nach Behandlung mit GA in einer Konzentration von 100 ppm und einer Eintauchzeit von 90 Minuten bei allen Sorten h?here Ertr?ge (Abb. 3). Alle Behandlungen führten zu Knollendeformationen, deren Anzahl sich mit der st?rker werdenden Konzentration von GA erh?hte (Abb. 4).

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Résumé Un traitement pendant 5 minutes à l'acide gibberellique (G.A.) à une concentration de 25 p.p.m. a avancé d'une semaine la germination de tubercules nouvellement récoltés des variétésUp-to-Date etVoran (Fig. 1, b et c). On a obtenu un semblable effet avecRoyal Kidney traitée à une concentration de 50 p.p.m. (Fig. 1 a). Quoique quelque germination apparaissait endéans 7 jours chez les tubercules traités, la germination à 100% ne se manifestait que 21 à 36 jours après le traitement. Un allongement des entre-noeuds suivait le traitement avec G.A. aux concentrations de 25, 50 et 100 p.p.m. Le traitement à 100 p.p.m. causait le plus grand allongement des entrenoeuds. Aux concentrations les plus élevées, l'accroissement maximum se manifestait entre les entre-noeuds 4 et 6 chezRoyal Kidney etVoran, et 4 et 7 chezUp-to-Date (Tableau). Le traitement au G.A. a un effet dépressif sur les indices foliaires chezRoyal Kidney etUp-to-Date, tandis que chezVoran l'effet est inverse (Fig. 2). Chez toutes les variétés, la production dans les expériences en pots est accrue par le traitement avec G.A. à 100 p.p.m. pendant 90 minutes (Fig. 3). Tous les plants traités produisent invariablement des tubercules déformés dont le nombre augmentait avec les concentrations de GA (Fig. 4).