Soil solarization in Greece

Soil solarization (SS) was tested in outdoor conditions in mid Greece by mulching wet soil with transparent polyethylene sheets to examine its effectiveness as a weed control treatment in maize and soybean planted as second season crops. Three or 4 weeks of solarization gave bet-ter weed control than preemergence herbicides and effectively controlled volunteer wheat (Triticum aestivum), Portulaca oleracea, Digitaria sanguinalis, Solanum nigrum, Amaranthus spp. and other weeds. The weed control effects lasted for more than 4 months. In mulched soil the maximum temperature at 7.5 cm depth was generally 7–9°C warmer than in the unmulched soil. Polyethylene thicknesses of 0.015–0.030 mm were equally effective. Plants grown on solarized plots out yielded those on clean weeded hoe treatments. The weed flora present caused maize and soybean losses of 20–48%. These losses would economically justify the use of polyethylene mulches. Solarisation du sol en grece La solarisation du sol (SS) a été testée en conditions extérieures en Grèce centrale, en recouvrant le sol humide avec des feuilles de polyéthylene transparent pour examiner son efficacité comme traitement herbicide sur du ma'is et du soja plantés comme secondes culturesde la saison. Trois ou 4 semaines de solarisation ont donné une meilleure destruction des adventices que des herbicides de pré1evée et ont détruit efficacement les repousses de blé (Triticum aesti-vum), Portulaca oleracea, Digitaria sanguinalis, Solanum nigrum, Amaranthus spp. et d'autres adventices. Les effets herbicides ont duré plus de 4 mois. Dans le sol couvert le maximum de témpérature à 7.5 cm de profondeur a été généale-ment de 7–9°C plus chaud qu'en sol nu. Des épaisseurs de polyéthylene de 0,015–0,030 mm ont é'té pareillement efficaces. Les plantes cul-tivées sur parcelles solarisées produisent autant que celles sur des sols tenus propres par binage. La flore adventice présente a entrainé des pertes de maïs et de soja de 20–48%. Ces pertes justi-fieraient économiquement l'utilisation de films de polyéthylène. Boden-Solarisation in Griechenland In Mittelgriechenland wurde die Solarisation feuchten Bodens, überdeckt mil transparenter Polyethylenfolie, auf ihre Wirksamkeit zur Unk-rautbekämpfung in Mais und Sojabohnen als 2. Kultur der Vegetationsperiode untersucht. Mit 3 oder 4 Wochen Solarisation ließen sich Weizenaufschlag (Triticum aestivum), Portulaca oleracea, Digitaria sanguinalis, Solanum nigrum, Amaranthus spp. und andere Unkräuter besser als mil Vorauflauf-Herbiziden bekämpfen. Die Wirkung hielt > 4 Monate an. Bei der Solarisa-tion lag die Bodentemperature in 7,5 cm Tiefe um 7.9°C höher als bei offenem Boden. Folien von 0,015.0,030 mm Stärke waren gleich wirk-sam. Der Ertrag lag in den solarisierten Parzellen über dem gehackter Parzellen. In den unbehan-delten Parzellen ging der Ertrag um 20.48% zurück, so daß die Solarisation unter Polyethylenfolie ein wirtschaftliches Verfahren ist.     

Toxicity of sodium fluoroacetate and zinc phosphide wheat grain baits to Microtus guentheri and Meriones tristrami

Whole wheat grains impregnated with 0.02, 0.05 and 0.2% sodium fluoroacetate, and 2% zinc phosphide, were offered to series of single caged individuals of Microtus guentheri and Meriones tristrami. In most cases the sodium fluoroacetate treated baits were well accepted by both species. The acceptance of the zinc phosphide-treated bait was partial in all the series tested. The approximate LD50 ranges of sodium fluoroacetate are between 0.24 and 0.43 mg kg⁻¹ for M. guentheri , and, perhaps, for the jirds too, and for zinc phosphide—between 32.6 and 58.8 mg kg⁻¹ for M. tristrami , and a similar value, more or less, for M. guentheri.     

Control of hooded crows by modified Australian traps

Modified Australian crow traps effectively protected crops, mainly in pecan orchards and watermelon fields, from the hooded crow, Corvus corone sardonius Kleinschmidt (Corvidae). The effects of modifications in trap construction and operation methods on trapping efficiency were studied. It was essential to use a lure crow, whereas the importance of bait was doubtful.     

The effects of ultraviolet-B (UV-B: 290–320 nm) radiation on blister blight disease of tea (Camellia sinensis)

Sunlight is known to reduce the incidence of blister blight disease of tea, caused by Exobasidium vexans . The effects of the ultraviolet-B (UV-B: 290–320 nm) component of solar radiation on the disease and the development of E. vexans were studied in the field in Sri Lanka using UV-screening filter materials held over a commercial crop. Exclusion of UV-B radiation by Polyester, which reduces fluxes in the UV-B region by approximately 75–85%, increased both the number of translucent spots (immature sites of infection) and number of sporulating blisters (mature sites of infection), but it had little or no effect on the sporulation of the pathogen. When basidiospores were artificially inoculated on leaves, and were exposed to full or filtered solar radiation, their survival and germination increased when UV-B wavelengths were removed; significant differences were found 62 h after inoculation. However, UV-B did not affect the extension of germ tubes. This study indicates that the UV-B component of solar radiation plays an important role in the natural regulation of blister blight disease in the field.     

Enquête sur les maladies fongiques de l'arachide (Arachis hypogaea) en Côte-d'Ivoire. I. Méthodes d'enquête et étude descriptive: les conditions culturales et les principales maladies

Groundnut diseases were surveyed in the various traditional cropping regions of Ivory Coast during 1982, 1983 and 1984. The methods used during the survey are described. A preliminary analysis of the results aimed at a characterization of a complex, multiple pathosystem is presented. The analysis especially focuses upon some foliar diseases, and particularly on rust, caused byPuccinia arachidis. The results show the great variability of the climates and of the agricultural techniques which are associated to groundnut cropping. The list of the fungal pathogens which affect groundnut is long: 16 have been identified during the survey, of which 6 are omnipresent in the various regions. A correspondence analysis was performed, allowing to describe the average development of the multiple pathosystem: groundnut-rust-leafsport-wilting fungi. Endemicity in tropical pathosystems is also analyzed in the case of the main foliar diseases (rust and Cercospora leafspots). More specifically, the epidemiology of groundnut rust in southern Ivory Coast is interpreted as regular, explosive epidemics developping on an endemic background. Every year epidemics develop in the northern and central areas too, most of their primary inoculum supposedly originating from the infested southern crops. Probably, intensification of agriculture will strongly favour rust disease.     

Case report: fibroma on the end of the tail of a cow

An unusual case of fibroma on the end of the tail of a 7-year-old cross-breed cow. The most prominent clinical findings were the size and weight of the tumour, and the tail length. The extension of the tail was apparently caused by the weight of the tumour.