Water circulation, groundwater outflow and nutrient dynamics in Mida creek, Kenya

The relationship between physical hydrodynamic processes and nutrients dynamics was investigated in Mida creek, a groundwater influenced mangrovefringed creek in Kenya between March 1996 and May 1997. The research involved spot and timeseries measurement of nitrate–nitrite, ammonia, silicates, phosphates, salinity, temperature, sealevel as well as tidal currents at seven stations located in the front, middle and backwater zones of the creek. Groundwater level as well as total dissolved solids' concentration, salinity, temperature and nutrients' concentration were also measured once every month in shallow wells (watertable<5m) located in the upper region of the creek. Results of the study show that nutrient concentrations vary with the tide and that, though there is no river drainage, they are of the same magnitude as in mangrove creeks with substantial river runoff. The peak concentrations of NH ₄ ⁺ –N (5.45M), NO ₂ –NO ₃ (5.63M), PO ₄ ^3– –P (0.58M) and SiO ₃ ^2– –Si (81.36M) in the creek occurred during flood tide, 2–3h before high waters. The (NO ₂ ^– + NO ₃ ^– )–N concentrations declined rapidly during ebb tide, reaching the minimum levels during low water. Contribution of groundwater seepage to the net nutrients flux (particularly on nitrite–nitrates) is largest in dry seasons. The study shows that groundwater outflow sustains the mangroves during periods of severe salinity stress and nutrients deficiency in dry seasons. This is essentially by limiting salinity increase and by boosting nutrient supply in dry seasons.     

Zur Massenvermehrung des Schlehenspinners,Orgyia antiqua (L.) 1971/72 in Bayern

Summary On an outbreak of Orgyia antiqua L. (Lepid., Lymantriidae) at Memmingen, Bavaria, 1972.The number of larvae ofO. antiqua on pine trees at Memmingen reached its high level during autumn 1971. About 350 ha mainly the old trees were infested. The number of egg masses per stem was more than 42 in max. with an average of 205 eggs per egg mass (n = 40). The percentage of hatching was found to be 74,5%. The rest of the eggs was mainly parasitized byTelenomus dalmanni (Ratz.). The pest had only one generation. The old larvae were infected with a virus disease and a great part of pupae was killed by fungi. These two diseases were the main factors in regulating the population ofO. antiqua.     

Bioassay of the Response ofTribolium Castaneum to Repellent Substance Excreted byTrogoderma granarium. Biotest der Reaktion vonTribolium castaneum (Col. Tenebrionidae) auf eine vonTrogoderma granarium (Col. Dermestidae) ausgeschiedene Repellent-Substanz.

Ohne Zusammenfassung     

Constituents of Carapa granatum fruits

The isolation of 6alpha,11beta-diacetoxygedunin (1) and other minor constituents from Carapa granatum fruits is reported.     

Lignin distribution in spruce (Picea abies) determined by mercurization with SEM-EDXA technique

Summary The lignin distribution between the middle lamella and the cell wall of spruce fibers has been determined by a new technique based on a mercurization of the lignin and a concomitant determination of mercury by the SEM-EDXA technique. The ratio of lignin in the middle lamella at the cell corners to the lignin in the secondary wall was 2.5±0.6 for latewood and 2.4±0.6 for earlywood. This gives a lignin content of 55–58% in the true middle lamella in the cell corners. The reactivity to mercuric acetate of different wood elements was determined in separate experiments. Fractions enriched in ray cells, middle lamella, and compression wood all reacted at the same rate as the whole wood; about one mole of mercury was incorporated per mole of lignin (C₉-unit).     

Untersuchungen zur Wirkung eines Kernpolyeder-Virus ausLeucoma salicis L. (Lep., Lymantriidae) auf einige Lymantriiden-Arten

Zusammenfassung Es wird ein Nuclear-Polyedrose-Virus ausLeucoma salicis-Raupen beschrieben und das Ergebnis von Untersuchungen über seine Wirkung auf 5 Lymantriiden-Arten mitgeteilt. Das Virus zeigte hohe Pathogenität gegenLymantria dispar, Euproctis chrysorrhoea, Leucoma salicis undOrgyia antiqua, dagegen geringe gegenLymantria monacha. Die Lt₅₀- und LD₅₀-Werte für die verschiedenen Wirte werden mitgeteilt.

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On cross infectivity of a nuclear polyhedrosis virus isolated fromLeucoma salicis to some related Lymantriidae

A virus strain isolated from larvae ofLeucoma salicis L. (Lep., Lymantriidae) was tested against 5 species of Lymantriidae. This virus showed a high pathogenicity againstLymantria dispar, Euproctis chrysorrhoea, Leucoma salicis andOrgyia antiqua. The nun moth,Lymantria monocha, was less suspectible to the nuclear polyhedrosis virus; this could be shown by aid of the calculated values of the Lt₅₀ and the LD₅₀.

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Mit 5 Abbildungen und 5 Tabellen     

Antifilarial activity of Azadirachta indica on cattle filarial parasite Setaria cervi

Alcohol and aqueous extracts of flowers of Azadirachta indica were tested in vitro for their potential antifilarial activity against whole worm, nerve muscle (n.m.) preparation and microfilariae of Setaria cervi. The effects of alcohol and aqueous extracts were similar in nature on the spontaneous movements of whole worm and nerve muscle preparation. On the whole worm, the response was characterized by initial increase in tone, rate and amplitude of contractions followed by reversible paralysis. The initial stimulant effect is likely to be due to irritant effect on the cuticle. Nerve muscle preparation responded to both extracts by inhibition of spontaneous movements followed by reversible paralysis; initial stimulation phase was absent. The inhibition was concentration related. Alcohol and aqueous extracts had almost similar lethal effect on the microfilariae of S. cervi, the LC50 being 15 and 18 ng/ml, respectively.