Erwinia carotovora (Jones) Bergey et al. var. atroseptica (Hellmers et Dowson) Dye. Seed Tuber Infection Versus Symptom Expression in the Field1

Based on the time that symptoms of blackleg become evident in the field and the various ways of inoculation, it is concluded that the spread of symptom expression is due to the depth at which the bacteria penetrate into the interior of the tubers. Moreover, it is demonstrated that it is not the closed lenticels which prevent penetration, but the absence of a waterfilm in the intercellular spaces of the tuber tissue.     

The effect of propionic acid on the storage losses of hay

Storage losses in moist hay treated with propionic acid were compared with those occurring in untreated moist hay in two experiments and with field-cured hay in three experiments. Dry matter losses in treated hays ranged from 41 to 8.6% and from 1.7 to 12.6% in untreated hays. Digestible organic matter losses in both treated and untreated hays were generally greater than dry matter losses. Only in one experiment did propionic acid application significantly reduce nutrient losses in moist hays. Nutrient losses, and water-soluble carbohydrate losses in particular, were shown to be correlated with maximum and cumulative bale temperatures during storage in two of the experiments. The rise in hale temperatures during storage was reduced in all three experiments, to a greater or lesser extent, by application of the additive. Loss of propionic acid from the hay during and after application was very large. In the three experiments 86.2, 85.3 and 85.6% of the acid applied was lost by the end of the storage period. Acid distribution studies indicated that variation in acid concentration within bales was as great as between bales. It was concluded that more research is needed into applicator design and position on the baler and into alternative application methods if the benefits of propionic acid as a moist hay preservative are to be fully exploited.     

Studies on Herpesvirus scophthalmi infection of turbot Scophthalmus maximus (L.): Histopathological observations

Abstract. The histological features of the disease caused by infection of turbot by Herpesvirus scophthalmi are described. Infection of epidermal cells of skin and gill resulted in the formation of giant cells showing a variety of nuclear and cytoplasmic changes associated with the replication of the virus. The effects of the condition together with possible control measures are discussed.     

THE EFFECT OF HISTAMINE ON SILAGE DRY-MATTER INTAKE

The oral introduction of 0·5 g histamine as the diphosphate into the rumen of sheep produced no effect on the physiological condition of the animals. The feeding of histamine, as the dihydrochloride, in levels up to 1 g/day to sheep on silage diets did not affect the dry-matter intake.     

Unsprouted potato tubers treated with gibberellic acid (GA3)

Summary Tubers (still unsprouted after an eight months' storage period) of the late varietyLibertas with slow growth in youth and few stems were treated with gibberellic acid (GA₃) in 1958 and 1959. Two sprayings gave similar results as dipping for 15 minutes. 25 ppm probably had more effect than 12,5 ppm. During both years the treatment resulted in more and longer sprouts and more stems, although the number of stems is usually less than the number of sprouts. Emergence was not accelerated and in both years yields tended to be lower. In 1958 all yields reached a high level, treatment gave a non-significant lower yield, but there was a greater number of tubers especially in the 25–40 mm seed-class. In 1959 the size and the number of tubers were affected by second growth owing to the unusually dry summer with short spells of rainy weather. In this year presprouted tubers emerged 10 days earlier than treated and non treated, unsprouted seed, which for a long period gave the crop a lead in haulm growth and even a permanent lead in tuber yield.

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Zusammenfassung Von der sp?ten SorteLibertas, die in ihrer Jugend ein langsames Wachstum zeigt und wenig Stengel entwickelt, wurden ungekeimte Knollen (nach 8-monatiger Lagerung) in den Jahren 1958 und 1959 mit Gibberellins?ure (GA₃) behandelt. Eine zweimalige Spritzung ergab zumindest ?hnliche Ergebnisse wie das Eintauchen w?hrend 15 Minuten. 25 ppm hat wahrscheinlich eine bessere Wirkung, wie 12,5 ppm. In beiden Jahren ergab die Behandlung mehr und l?ngere Keime sowie mehr Stengel, obzwar die Anzahl der Stengel gew?hnlich nicht so hoch ist, wie die Anzahl der Keime. Es zeigte sich keine Beschleunigung des Auflaufens, jedoch eine Tendenz für einen geringeren Ertrag in beiden Jahren. In 1958 waren alle Ertr?ge hoch und die Behandlung ergab eine nicht signifikante Ertragsverminderung, jedoch eine gr?ssere Knollenzahl (insbesondere in der Saat-Gr?ssenklasse, 25–40 mm). In 1959 war die Gr?sse und die Anzahl der Knollen infolge des ungew?hnlich trockenen Sommers mit kurzen Regenperioden durch Mehrwüchsigkeit beeintr?chtigt. In diesem Jahr sind die vorgekeimten Knollen um 10 Tage früher aufgelaufen, was den Pflanzen im Vergleich zu den behandelten und nicht behandelten ungekeimten Pflanzgut einen l?ngeren Vorsprung im Krautwuchs und einen dauerhaften Vorsprung in der Knollenbildung gab.

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Résumé Des tubercules non germés (après stockage pendant huit mois) de la variété tardiveLibertas, à lente croissance de début et à petit nombre de tiges, ont été traités à l'acide gibberellique (GA₃) en 1958 et en 1959. Deux pulvérisations donnaient des résultats au moins égaux à ceux d'une immersion de 15 minutes. La concentration de 25 millionièmes est probablement plus efficace que celle de 12,5 millionièmes. L'une et l'autre année, les tubercules traités avaient des germes plus nombreux et plus longs et un plus grand nombre de tiges, bien que le nombre de tiges ne soit généralement pas aussi grand que le nombre de germes. La levée ne fut pas accélérée et il se manifesta une tendance de diminution du rendement. En 1958, toutes les récoltes furent bonnes, le traitement entra?nant une diminution non significante de la récolte mais faisant augmenter le nombre de tubercules (particulièrement dans la catégorie de semenceaux de 25–40 mm). En 1959, la grosseur et le nombre des tubercules furent influencés par croissance secondaire (excroissance) par suite de l'été exceptionnellement sec avec de courtes périodes de pluie. Cette année-là, les tubercules prégermés levèrent 10 jours plus t?t que les plants non prégermés, traités et non traités, de sorte que le développement du feuillage fut supérieur pendant une longue période et que celui des tubercules fut supérieur jusqu'à la récolte.